Keto diet and nausea

Ketogenic diet enthusiasts love talking about how great they feel eating loads of fat and very few carbs. (No more brain fog! Zero sugar cravings!) What they might not mention? Going from a regular diet to a keto diet can temporarily cause some pretty unpleasant side effects.

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We’re talking about keto flu—a cluster of flu-like symptoms that many newbies experience in the early days of adopting a ketogenic diet—and it’s not exactly fun. Whether you’re thinking of committing to a keto way of life or you’re already on the keto bandwagon, there are a few things you should know about the keto flu.


What is the keto flu? What are the symptoms?

Keto flu is a group of side effects that hit most people when they first switch from a higher carb diet to a ketogenic one. Many of them are similar to what you might feel like when you have the actual flu (hence the name). Keto flu symptoms typically include things like:

Bad breath Weakness or fatigue Headache Nausea Muscle cramps Diarrhea or constipation Skin rashes Mood swings

Why the heck does it happen? Normally, the body uses glucose—or sugar—as its main source of energy. When you cut your carbs below 50 grams per day (the typical threshold for a ketogenic diet), you enter a metabolic state called ketosis: Instead of burning carbs for fuel, your body begins burning ketones—an alternative fuel source that the liver makes by breaking down fat. In turn, this can make you feel run down.

That sounds awful. How long does the keto flu last?

Ketosis is pretty different from what your body is used to, and this onslaught of symptoms is its way of dealing with carb withdrawal—and adapting, explains Kristen Mancinelli, RD, author of The Ketogenic Diet. “It takes a while, usually a week or two, for the metabolic machinery to shift to fat-burning mode. And you’ll feel pretty crummy while the transition is happening,” she says.

Keto flu symptoms can start to kick in within a day or two of adopting a ketogenic diet, Mancinelli says. If you recently cut your carbs below 50 grams daily and soon notice that you feel downright awful, you’ve probably got a case of keto flu.

That’s not to say everyone starting out on a keto diet ends up wholly incapacitated for days. “You might find that you fatigue more quickly or that exercise seems harder than normal,” says Seattle-based nutritionist and Academy of Nutrition and Dietetics spokesperson Ginger Hultin, MS, RDN. Your body might also have an easier time transitioning (read: fewer symptoms) if you were already eating a relatively low-carb diet, Mancinelli explains.

Is keto flu dangerous? Do I need to call my doctor?

Adopting a keto diet for the short term is generally considered safe, and any symptoms you might experience will typically clear up within a couple weeks, Hultin explains. (The jury’s still out on how eating this way might impact your body long-term.)

When you’re on the keto diet, you need to drink more fluids than normal to avoid dehydration.

That said, it’s a good idea to work with a doctor or registered dietitian before you start eating keto—and continue to check in with them while you adapt to your new diet, recommends David Nico, PhD, author of Diet Diagnosis. Planning ahead can help you steer clear of nutritional deficiencies that can strike when you cut most carbs out of your diet. And doing so might also help minimize your keto flu symptoms.

For instance, working with an expert can reduce the risk for dehydration—which can make keto flu symptoms like headache, cramping, nausea, and fatigue worse. Drastically slashing carbs causes the body to excrete a higher volume of water and electrolytes, so you may need to drink more liquids and eat more salt to stay adequately hydrated, Mancinelli explains. How much more is different depending on things like your activity level and age, but a pro can help determine the right amount for you.

Is keto flu contagious?

While influenza is a virus that’s spread by close contact, keto flu isn’t something you catch. You’ll only experience symptoms if you enter a state of ketosis, and it’s not contagious.

Is there anything I can do to avoid keto flu?

Sorry, but probably not. Ketosis affects some people more than others, but there’s a good chance you’ll notice at least some side effects as your body adjusts to a (nearly) carb-free diet. The good news? There are a few steps you can take to keep things as pleasant as possible:

Stay hydrated

Remember, your water and electrolyte intake needs to go up on a keto diet, and dehydration can exacerbate many keto flu symptoms. There’s no hard and fast recommendation for how much water keto dieters should be drinking, Nico says. But in general, you should be sipping enough so that your urine stays clear or pale yellow. As for electrolytes like sodium? A registered dietitian can help you figure out how much more you should be having and the best places to get it. If you’re feeling sick and can’t see a nutritionist right away, consider mixing a low-carb electrolyte drink into your water.

Nuun Hydration Vitamin + Electrolyte Drink Tablets $24.20 GU Hydration Drink Tablets $8.15 Electrolyte Replacement Tablets for Rapid Rehydration $24.95 Hydralyte Effervescent Electrolyte Tablets $9.44

Don’t push yourself

Stick with light exercise like walking—or take a break if you’re really pooped. “It may be best to take it easy and give your body time to adjust,” Hultin says.

Stick to your guns

Your symptoms will clear up as your body gets used to burning fat as fuel—so don’t confuse it by splurging on a bowl of pasta. “If you aren’t vigilant about sticking with your keto diet, you’ll never fully transition,” Mancinelli says.

The bottom line: The keto flu is temporary and common among keto diet newbies. Consulting with a nutritionist before starting the keto diet may help ward off uncomfortable symptoms. If you already have keto flu, listen to your body, take it easy, and make sure you stay adequately hydrated to ease the symptoms.

Marygrace Taylor Marygrace Taylor is a health and wellness writer for Prevention, Parade, Women’s Health, Redbook, and others.

Why do I Feel Nauseous After Eating on Keto?

The first few weeks of starting a ketogenic diet can be particularly rough, especially if your new regimen is different from your typical nutrition intake prior to keto. Many people experience some digestion issues when cutting out carbs and introducing more fat into their daily diets than their bodies are typically used to. Along with digestion issues, other side effects of this transition period can include irritability, mood swings, headaches, and in some extreme cases increased anxiety and depression. This disruptive initial period of entering ketosis is most commonly referred to as the “Keto Flu”

What Exactly is the Keto Flu?

The Keto Flu, otherwise known as the “Carb Flu” is a resulting state of sickness that tends to afflict many people just getting settled into a new ketogenic diet. The symptoms associated with the keto flu include nausea, sweatiness, headaches, drowsiness, and irritability. These symptoms arise because your body is going through a phase similar to that of withdrawal, where your blood glucose levels are trying to adjust and find their balance without a carbohydrate-rich diet.

In standard everyday diets, your body uses carbs as fuel to burn and its primary energy source, but when you switch to a low carb/high fat and high protein diet, it will take some time to fully adjust to burning up fat more efficiently than the glucose from carbs. For the average person, the Keto Flu only really lasts up to a week, or often less than that. However, in extreme cases it can last for up to a month.

Electrolytes are More Important Than You Think

Introducing additional sources of electrolytes into your daily diet is one of the best ways to fight off the fatigue and other symptoms of the Keto Flu. A lack of electrolytes in one’s diet can be a primary cause of fatigue, or if anything definitely exacerbate the symptom of fatigue already present in the Keto Flu.

The tricky thing about getting enough electrolytes on the keto diet, is that most sports drinks that come to mind when you think “electrolytes” are actually full of sugars and therefore carbs. Electrolyte supplements are a great way to get that fuel for your body without risking pulling your body out of ketosis. Some keto-friendly supplements to keep an eye out for will also have healthy quantities of potassium, sodium, calcium, chloride, and magnesium.

Those nutrients listed above can also be found in plenty of low carb foods as well. Here are some keto-friendly electrolyte-boosting foods for example:


  • Plain Yogurt
  • Mushrooms
  • Spinach
  • Kale
  • Salmon
  • Tuna
  • Avocados
  • Nuts


  • Olives
  • Seaweed
  • Broccoli
  • Cauliflower


  • Soup/Broth
  • Sauerkraut
  • Pickles
  • Bacon


  • Cheese
  • Seafood (sardines)
  • Almonds
  • Leafy Vegetables


  • Dark Chocolate
  • Artichokes
  • Fish
  • Spinach


  • Seeds
  • Meats
  • Nuts
  • Dark Chocolate
  • Coconut/Coconut Water

You can also get a lot of these important nutrients from supplements if you have dietary restrictions. I usually utilize supplements for my Magnesium and Potassium intake.

Taking about 400mg daily of Magnesium a great place to start. I get mine in the form of Magtein on

For Potassium, I’m partial to the Keto Vitals Electrolyte Capsules, which are usually on sale on as well.

Eat More Fat

It seems almost counterintuitive at first, but eating more healthy fats will help speed up the ketosis process and get your body to start efficiently burning fat as fuel. A bonus in consuming more fat, is they often help curb cravings in a similar way that most carbs do. Loading up on coconut oil, avocado, or eggs is a great way to help your body grow accustomed to the new keto diet.

Get Lots of Rest

Getting optimal sleep is vital when adapting to a new diet, especially one as intensive on your health as the ketogenic diet. Additionally, the new balance of proteins and fat, and lack of carbs will effect how efficiently you build muscle mass, which is highly dependent on the amount of rest you get each night. By getting enough or potentially more rest than usual, you’ll help your body fire on all cylinders to process fats and burn them more efficiently.

On the keto diet, you should aim to get between 7-9 hours of sleep every night, but insomnia is a present symptom in a lot of new keto dieters. If you still find yourself feeling tired or even drained during the day, mid to late day naps or calm meditations are highly recommended as well. Furthermore, incorporating more magnesium into your diet can help bounds with improving the quality of your sleep.

How can I Prevent Nausea?

One of the best proven ways to prevent nausea is to eat slower. Many people find that eating too quickly directly causes indigestion, which on keto can exacerbate already present digestion issues. Additionally, keeping portion sizes small and more frequent while eating at an overall slower pace will help your body process foods in a natural, and healthy manner, thus preventing any unnecessary discomfort.

Steering clear of sweet foods, even if keto friendly is ultimately a good call. Even trace amounts of sugar can upset the stomach, especially during periods of adapting to a new diet plan. Staying away from fried or greasy foods are beneficial too. While many keto experts recommend replacing carb-heavy cravings for friend food with coconut oil, all that grease can give rise to some serious nausea and indigestion if eaten in excess.

Alcohol is also obviously a big contributor to nausea, despite whatever diet they may be on. While alcohol isn’t typically endorsed on a ketogenic diet, it is technically allowed in moderation. Drinking alcohol in low moderation is vital to both maintaining a state of ketosis, and preventing future nausea. You can learn more about the limits of alcohol on the keto diet from our guide here.

Check Your Carb Counts

While the keto diet requires that you cut your carbohydrate intake severely down, you still do need some to keep your body functioning normally and safely. Whens some people first venture into the keto diet, they can actually consume too few carbohydrates, and end up causing their body to get sick. While it is important to limit your carbs, it is safe to have a bare minimum amount in order to help your body digest your food and prevent nausea.

Don’t Forget to Exercise

Lastly, low-intensity exercises can be a great way to curb nausea and keep your body regular. Low-intensity exercises such as long morning walks, moderate stretching exercises, and some light weight training can help your body build muscle mass and improve digestion – just don’t forget to stay hydrated and replenish electrolytes whenever possible.

Tamra Judge Quit the Keto Diet After it Made Her Sick: ‘It Doesn’t Work’

Tamra Judge Charles Sykes/Bravo/NBCU Photo Bank via Getty Images

It feels like every celebrity is on the keto diet these days, but not all are fans — The Real Housewives of Orange County‘s Tamra Judge said she had to quit the diet after it made her “sick.”

The bodybuilding reality star, 51, is all about healthy eating and high-protein meals, but she had to bail on keto after a month.

Judge was following the high-fat, high-protein and low-carb plan “until I got sick,” she told the Bravo blog The Feast. “They say there’s this keto flu you get, and I just fell off the keto wagon.”

The keto flu is a well-known side effect, with dieters experiencing influenza-like symptoms such as body aches, fatigue, dizziness and nausea. According to Women’s Health, doctors believe that its because the body is going through withdrawal as it switches to burning fat for energy instead of carbs, a process called ketosis (which is how the keto diet earned its name).

After her experience, Judge isn’t a fan of the keto diet.

“It concerns me,” she said. “I’m sure it works, but I cannot wrap my brain around eating that much fat. Bad fat — cheese, sour cream, butter, all that stuff. So, I like to do the good fats — like I’ll do the avocado, but I’m not gonna drown my eggs in butter and throw the cheese of top of it. Just — I can’t.”

Judge believes that people are losing weight on keto, but in an unhealthy way.

“It just doesn’t make any sense to me because it’s just not healthy eating,” she said. “So I worry more about what it’s gonna do for, like, your heart, your cholesterol, and things like that.”

RELATED VIDEO: Jillian Michaels Slams Fad Diets: “Don’t Do Keto”

And, she adds, the ketosis process has to be going at all times for it to actually be effective.

“The problem is it doesn’t work. You have to put your body in Ketosis and if you don’t, then you’re just eating a s—load of calories,” she said. “But if you’re eating carbohydrates with that and sugar — all you’re doing is eating a whole lot of calories. You know what? It’s not gonna work. I think people don’t quite understand how the keto diet works.”

Instead, Judge said, she prefers her usual diet of lean proteins, vegetables (which are not a big part of the keto diet) and healthy fats.

“I pretty much stick to a similar diet, but I just don’t go for the bad fat,” she said.

Photo: Twenty20

It’s almost a universally accepted fact that diets leave you hungry. After all, that rumbling tummy two hours after mealtime (not to mention, strict and time-consuming calorie counting) is the reason most New Year’s resolutions fail by February, right? But Dr. Jacob Wilson and Ryan Lowery, the authors of The Ketogenic Bible, say you don’t need to go hungry or count calories to lose weight.

The ketogenic diet, also referred to as “keto,” is a dieting method gaining popularity from people with diabetes to CrossFitters. “The ketogenic diet induces ketosis, which is a state where your body is running primarily off of fat and ketones,” explains Wilson, instead of sugar from carbs. “That can occur through lowering your carbohydrates and having very high fat intake.” Specifically, the ketogenic diet targets about 80 percent of calories from fat, 15 percent from protein and 5 percent from carbohydrates.

RELATED: Why You Should Eat More Fat and Less Sugar

The Upside of Ketosis

While this method may have gained popularity among athletes and other hard-core fitness buffs, they’re far from the only ones who will see benefits from this method. “When you implement a well-formulated proper ketogenic diet, you can see improvement in performance and body composition at the same time,” says Lowery. You’ll look leaner and shed fat, but you won’t feel sapped of energy like when you decrease calories. The bonus is you won’t experience the post-meal crash associated with a higher-carb diet, he says.

Lowery also says that for most ketogenic diet newbies, there won’t be a need to count overall calories either. As long as you’re paying attention to your diet and inducing ketosis through high-fat and low-carb consumption, most dieters automatically hit a calorie intake that allows weight loss. (Over time, it may become necessary to pay attention to both macronutrients and calories.)

RELATED: Is Weight Loss Really As Easy As Calories In, Calories Out?

So How Does the Ketogenic Diet Work?

Consuming fewer calories means weight loss, but fewer calories also means you’re going to be hungry more often than not. The ketogenic diet avoids this pitfall by making the majority of the calories you consume fat. Fat is very satiating, say Lowery and Wilson, so a very high-fat diet will help you feel fuller for longer.

In addition, keto-enthusiasts say you’ll also have more energy, feel more alert and possibly even experience other neurological benefits. “If my diet is primarily carbohydrates, is going to select that as it’s primary fuel source. If I eat primarily carbohydrates, my body will use more carbohydrates,” says Wilson. But by dramatically lowering carb intake and inducing ketosis, you can force the body to burn fat for energy instead of carbs. Carbs aren’t necessarily bad or good, but if you consume too many high GI (glycemic index) carbs, you can increase insulin production, which leads to weight gain, and in worse instances, type 2 diabetes and heart disease.

Even a lean individual, Wilson explains, can carry around about 50,000 calories of energy in the form of fat on their body. By eating less and inducing ketosis, you make it easier for the body to tap into the energy reserves it already has on hand, keeping you energized between meals.

While there is research indicating that a high-fat diet could be very harmful, Wilson and Lowery are quick to point out that this is only the case when you’re consuming both high-fat and high-carb foods. If you haven’t induced ketosis, or forced the body to start metabolizing fat, then a high-fat diet can be harmful. However, research shows that an ultra-high-fat and low-carb diet might be beneficial for weight loss while still preserving muscle and strength.

RELATED: The Ultimate Guide to Pre and Post-Workout Carbohydrates

Making Ketosis Work for You

As a first step to ketosis, Lowery and Wilson recommend cutting out as many high-carb foods from your diet as possible: bread, pasta, rice, grains and sweets. In the meantime, you’ll want to significantly up your fat intake. Think: high-fat animal proteins, like fish, meat and eggs, and plant-based fats, like avocados, oils and some nuts. Once you’ve mastered ketosis, you’ll begin focusing on the variety and quality of fats, but for now, fat is fat.

After you’ve eliminated the most obvious sources of carbs, look to dairy, fruit and condiments, which can sneak in surprising amounts of carbs. Lowery and Wilson say you should aim to get most of your roughly 30 grams of carbs daily from fiber instead of sugar. That fiber can often be found in foods like leafy greens and other veggies — but again, beware of the high-carb count that some veggies, such as sweet potatoes and squash, may have.

Perhaps the most important step is to get into a state of ketosis as quickly as possible. Lowery and Wilson warn of a transition period of a few days commonly known as the “keto flu.” As your body adjusts to its new fat-based energy source, you may feel tired, groggy and grumpy. It’s essential to move through this period as quickly as possible in order to make it to ketosis and see the results that will keep you motivated to continue.

RELATED: 11 Healthy Zucchini Recipes for Low-Carb Meals

The Downsides of the Ketogenic Diet

Obviously, that transition period can be a big “con” when it comes to embarking on a ketogenic diet, though our experts insist it’s worth it. Also good to know: They say you shouldn’t usually have to go back through that difficult transition period if you slip out of keto for just a few days. (Good news if you’re going home to visit mom and her cooking or vacationing in a carb-heavy part of the world.) You can usually tell you’ve gone out of ketosis when you’re experiencing grogginess or low-energy like you may have before the ketogenic diet.

It’s also important to note that a ketogenic diet can make it easier to become dehydrated and lose electrolytes, so it’s essential to stay hydrated and replace electrolytes like potassium, sodium and magnesium in your diet or with supplements.

Finally, when researching or talking about the ketogenic diet, you may encounter a common myth that ketosis leads to ketoacidosis. “That’s a condition typically only seen in uncontrolled diabetes,” Lowery says. “You’ll never achieve that state on a well-formulated ketogenic diet.” Unless you suffer from one of a handful of medical issues (like impaired functioning of the kidneys, gall bladder, pancreas or liver, for example), a ketogenic diet is perfectly safe, he says. Having a “well-formulated diet,” though, does mean you do need to plan, prepare and think about your diet far more than you may be used to, especially at the beginning. Want to know what keto might look like for you? Here’s a keto-approved recipe to get you started:

Photo: Courtesy of Victory Belt Publishing

Get the Brie Sirloin Sliders Recipe by clicking here.

For more on the Ketogenic Diet, pick up The Ketogenic Bible: The Authoritative Guide to Ketosis wherever books are sold on May 30.


While the buzz seems to be heating up around the ketogenic diet, the eating philosophy isn’t new. In fact, it’s been used as a treatment for epilepsy since the 1920s and came back into the spotlight in the ‘90s when Dateline ran a segment highlighting it as a treatment option. But how did it go from epilepsy treatment to weight-loss regimen? Well, for starters, more and more celebs — including Vanessa Hudgens and Halle Berry — have recently praised its weight-loss results publicly.

So what is the ketogenic diet? It’s a high-fat, low-carb diet that sends your body into a state of ketosis, during which it uses stored fat as energy. When you eat this way — typically we’re talking less than 50 grams of carbohydrates a day — “you’ll consume an enormous amount of fat,” says Shahzadi Devje, RD, CDE, a dietitian in Toronto, Canada. In fact, by following the keto diet, about 60 to 80 percent of your daily calories will come from fat. When you restrict carbs this way and eat more fat, your body takes about 24 to 48 hours to begin producing ketones, which are created when your body metabolizes fat for energy, says Pegah Jalali, MS, RD, a clinical coordinator at the New York University Comprehensive Epilepsy Center, where she counsels patients on the ketogenic diet. Normally, your body would metabolize carbohydrates as a primary source of energy.

By following the keto diet, about 60 to 80 percent of your daily calories will come from fat.

When most people hear “diet” they think calories, but on the keto diet specific caloric intake isn’t the focus. “Mostly, I encourage my patients to eat according to their appetites,” says Jalali. “Your body can be in a ketogenic state at a range of calorie levels, and individual needs fluctuate day to day depending on activity and other factors.” But you won’t want to add a latte to your morning routine or even an extra piece of fruit to your afternoon snack, if those weren’t on your meal plan, says Jalali. “If you eat a lot more, then you risk coming out of ketosis — and if you do not eat enough fat, you also risk coming out of ketosis.” Bottom line: When you follow the keto diet, you must do so to a T for it to be effective. If you introduce cheat meals or cheat days, you’d be eating a high-fat diet and bringing your body out of that fat-burning ketosis state, which could have negative health consequences.

What does a day on the diet look like?

As an example of what a day in the life of the ketogenic diet may look like, here is a sample meal plan that Jalali shares with her patients.


  • 2 eggs, cooked in 1 tablespoon of butter or ghee
  • ½ cup cooked spinach, in 1 tablespoon coconut oil
  • 1 cup coffee, blended with 1 tablespoon butter and a dash of cinnamon

Mid-morning snack

  • 6 macadamia nuts
  • 6 raspberries


  • Tuna salad (4-5 ounces canned light tuna, mixed with 2 tablespoons mayonnaise, ¼ cup chopped celery, ¼ cup chopped green apple, and salt and black pepper to taste), served over 1 cup Romaine lettuce
  • Salad (½ cup steamed green beans and 8-10 olives), topped with a mixture of 1 tablespoon olive oil and ½ lemon, juiced

Afternoon snack

  • ½ avocado, sprinkled with 1 tablespoon hemp seeds or 1 teaspoon nutritional yeast

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  • 8-12 ounces cooked steak, in 1 tablespoon butter
  • 1 cup cauliflower, roasted in 1 tablespoon hazelnut oil


  • 1 ounce 90 percent dark chocolate
  • 1 tablespoon crunchy salted almond butter, sprinkled with a dash of cinnamon

The pros of the Keto Diet

A main benefit of the diet, and why many of its followers praise the eating plan, is weight loss. Multiple studies show promising results: In a study in The American Journal of Clinical Nutrition, obese men dropped about 14 pounds after following the diet for a month. And in a longer-term study published in Clinical Cardiology, obese adults adhering to a ketogenic diet for about six months noticed significant weight loss — on average, 32 pounds — as well as reductions in total cholesterol and increases in beneficial HDL cholesterol. A review study in the European Journal of Clinical Nutrition also found that the weight loss seen within the first three to six months of following the keto diet was greater than the loss from following a regular balanced eating style.

Weight loss often occurs on the keto diet because your body is utilizing fat stores for energy — and you may also notice a decreased appetite that often results from the diet. “We don’t know exactly why ketones suppress appetite,” says Jalali. “But my theory is that ketosis is the state we are in during starvation and prolonged fasting, so it might be an evolutionary response to help humans cope.” Plus, your body digests fat a lot more slowly than carbs. “Fat has a longer intestinal transit time compared with carbs,” she says. “So it will prolong that feeling of fullness, especially in between meals.”

While some say following the diet claim it is limiting at food-related social occasions, Lara Clevenger, MSH, RDN, a dietitian in Edgewater, Florida, says you can easily plan ahead. “I currently follow a ketogenic diet, and eating out is a lot easier than people think,” she says. “You can ask for a burger minus the bun and fries, plus a side of veggies. Or order a chef salad and ask for olive oil as your dressing, minus the croutons. The options are plentiful!” Clevenger says she first started the keto diet for its anti-inflammatory benefits, due to a family history of obesity, hypertension, breast cancer, diabetes and dementia. “I will stay on a ketogenic diet for the foreseeable future,” she says. “I now have two to three times more energy, I no longer have trouble falling asleep and staying asleep, I am better in tune with my hunger and satiety, and I am no longer addicted to sugar. The diet has had more of an impact than I could have imagined!”

In addition to weight loss, studies show that the ketogenic diet may also be helpful in treating many other conditions, such as type 2 diabetes, polycystic ovary syndrome (PCOS), acne and more.

The cons of the Keto Diet

“As with any diet, there are always pros and cons,” says Devje. If you follow the ketogenic diet, you may notice side effects such as bad breath, headaches, nausea and fatigue. The negative symptoms some experience when first starting the diet is often referred to as the “keto flu.” This feeling of tiredness is due to a drop in blood sugar that can cause lethargy, which usually passes in 24 to 48 hours, notes Jalali. You might also feel bloated or constipated — and you may feel the need to urinate more frequently, since ketosis acts as a diuretic, says Jalali.

Because the ketogenic diet is limited in terms of food groups, you’ll be at risk for nutrient deficiencies. “The diet requires a robust supplement regimen, since you can develop certain deficiencies on a ketogenic diet that can inhibit your ability to stay in ketosis,” says Jalali. “You can also develop micronutrient deficiencies that can cause hair loss, and a lot of people become constipated on a ketogenic diet.” Jalali recommends discussing the diet with both a physician and a ketogenic dietitian to work to prevent these side effects.

And if you’re following the diet for weight loss, it’s important to know that you may gain weight back when and if you go back to your normal eating habits. “A ketogenic diet is fantastic for some people, but it’s not a lifelong diet for everyone,” says Jalali, who says she sees benefits for people with chronic conditions such as epilepsy, type 2 diabetes and PCOS — but sometimes negative effects for people who go on the diet for weight loss. “A lot of patients find that when they come off the diet, they regain weight very easily,” she says. “The theory is that by being on the ketogenic diet for a prolonged period of time, their bodies become very sensitive and efficient at metabolizing carbohydrates.” Jalali notes that these patients may be able to maintain the weight loss by sticking with a low-carbohydrate diet. While more research on weight-loss maintenance after following the keto diet is needed, research shows that cycles of brief ketogenic Mediterranean diet periods, separated by longer periods of the Mediterranean diet, over one year helped obese adults maintain weight loss.

There are some groups who shouldn’t take the keto diet for a test drive. It can be dangerous for people with type 1 diabetes, as it can increase the risk for life-threatening diabetic ketoacidosis (DKA). Even people with type 2 diabetes following a ketogenic diet should regularly test their blood sugar and ketone levels to prevent DKA. If you have kidney disease, you’d want to skip this diet because you’d need to limit your protein intake. And if you have a history of disordered eating, the diet severely limits carbs and takes a lot of control to follow — which may increase the risk of bingeing or compulsive overeating. Consult with your doctor to determine if this is the right diet for you.

What’s the bottom line?

If you’re planning to follow the keto diet, consider consulting with a registered dietitian to determine the most balanced diet possible, as well as any supplements you may need to take. “Without monitoring by a licensed healthcare professional, challenges like poor bone health, gastrointestinal reflux, and changes in cholesterol levels can go unchecked,” says Julie Stefanski, RD, a registered dietitian in York, Pennsylvania. Getting a balance of nutrients on the ketogenic diet can be challenging, which is “no surprise because you’re essentially cutting out healthy whole grains, fruits and some vegetables,” says Devje.

And daily carbohydrate allowances on the keto diet will vary from person to person. “Some adults will have to consume 15 grams of net carbohydrates to stay in ketosis, whereas some professional athletes may be able to consume more than 120 grams of net carbs and be in a ketogenic state,” says Jalali. “This is another reason why it is best to work with a professional to design the diet.”

Because the keto diet is high in fat, you’ll want to make sure to incorporate more healthy fats into your eating plan. These include omega-3s, such as those found in salmon and sardines, as well as monounsaturated fats present in avocado, walnuts, almonds and sunflower seeds.

We don’t have a clear picture on the long-term benefits of the keto diet for weight loss. “Although there seems to be a short-term advantage of the ketogenic diet for weight loss, the advantage seems to shrink at the one-year mark,” says Devje. “The long-term safety of the ketogenic diet is yet to be determined.”

NEXT: Why losing weight too quickly may backfire in the long run

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Keto Made Me Thinner — Here’s Why I Quit the Diet

Medically reviewed by Kelly Kennedy, RD

When I stepped on the scale, and the needle raced past 200, I knew I had a problem. I was always thin and active as a young man. In college, I was 5 feet 10 inches tall and weighed 154 pounds (lbs). Now, closing in on a half-century of life, over two decades of desk jobs had since passed. The birth of my son made sleeping more of a hobby than a necessity. The long hours and the stress of owning my own business caused me to make my food choices based on speed and price rather than nutrition and fuel. My body was running on Coca-Cola, bagels, and pizza. So I shouldn’t have been surprised when the needle on the scale settled at 208 pounds, but I was still shocked. You never think you are going to become a statistic. But as more and more Americans become overweight, I was part of a not-so-exclusive club.

When I started looking into ways to lose weight, it was hard to avoid the ketogenic diet. In my mind, it was the latest in a long line of diets that have raced through popular culture in my lifetime: Atkins, South Beach, Zone, paleo. It seemed like there was a new magic solution every few years. The difference with keto was that although I was giving up a lot of things I really liked (pizza, pasta, soda), there were quite a few foods that were staples of the diet that I enjoy (meat, fish, spinach, broccoli). I wasn’t quite ready to make the commitment to such a strict diet, but I decided to take some baby steps.

After a day of feeling extremely depressed, I decided to try to make my worst trip to the scale the best thing that ever happened to me. It wasn’t too late to change. At least I hoped it wasn’t. Every two weeks, I replaced something awful in my diet with something a little bit better. First, day-long Coke drinking was replaced by a maximum of two small Gatorades per day. That dropped the number of calories I was drinking from 1,000 to 220 each day. Two weeks later, bagels were next to go, replaced by two simple scrambled eggs for breakfast. By making those two changes, I lost 15 lbs in less than a month. I wasn’t that far under 200 again, but it was a start. Increasingly restricting my simple carbohydrates was beginning to show immediate results.

If I was going to lose more weight, I needed to move around more. I started by walking to and from my son’s school to drop him off and pick him up each day. Each way was about 2 miles. Three weeks later, I was at about 185. Then I leveled off again.

To try to push through the plateau, I joined a boxing gym. I started with an amazing trainer named Joey Gamache. He is a former world champion, and he made me feel like a champion as well. Joey and I would try to train together four mornings per week — hitting the heavy bag and the speed bag, doing footwork drills. If you’re feeling as out of shape as I was then, you might think a boxing gym may not be a welcoming place for someone who is older, heavier, and a lot slower than they once were. It was the opposite. The people at Church Street Boxing Gym in New York City welcomed me with open arms.

Within three months, I knew everyone at the gym by their first name, something that never happened to me at health clubs. Even the professional fighters would give me a fist bump on the way to their morning workout. We weren’t competitors. We were all on the same team. The enemy was the couch and the TV. Every morning I was in the gym, I was with the extended family I never knew I was looking for. We were choosing life together.

RELATED: 10 Amazing Benefits of Exercise

Stalled Weight Loss Led Me to Consider the Keto Diet

Four months into my new journey toward health, my weight had dropped from 208 to 168 lbs. In boxing terms, I had gone from a super heavyweight to a super middleweight. I was at my goal, and I felt great! When I got to 168 lbs, some of my friends at the gym thought that based on my body composition, I could easily make it down to 160 (middleweight). But once I got to 168, the weight was no longer coming off as quickly. By now I had eliminated most of the carbs in my diet, but I wasn’t following the ketogenic diet to the letter.

Nowadays, the keto diet is well known, arguably the biggest weight loss diet fad out there. But at the time, it was news to me. My thought process went something like this: “You mean there’s a diet that actually uses your body’s extra fat for energy? Where do I sign up?” Even though there were signs of life in my abs, going keto sounded like the perfect way to burn off the love handles and any other extra body fat that was clinging to my body for survival.

After doing some closer examination, I learned quite a bit about the diet. It turns out that the keto diet traces back to the 1920s, when doctors were trying to find a way to mimic the effects of fasting in children with epilepsy to lessen the frequency of their seizures, according to a report in Epilepsia.

A traditional keto diet menu consists of foods that are high in fat, extremely low in carbohydrates, with a moderate amount of protein to allow the body to repair itself. The diet fell into a more complementary role in the 1930s, when antiseizure medications were developed.

But when you look at how keto works, it’s not all so surprising that the high-fat diet has gained popularity as a quick way to lose weight. By inducing the natural metabolic state of ketosis, the body begins to use fat as a source of fuel instead of carbohydrates. When the body breaks down fat, it produces metabolites called ketones, which your body then uses for energy in place of carbohydrates.

When I saw the foods that were listed as being keto-friendly — chicken, eggs, and cheese — I thought this was something I could do.

There are several different types of ketogenic diets. I opted to try the standard keto diet, which includes getting 80 percent of calories from fat, 15 percent of calories from protein, and only 5 percent of calories from carbohydrates. That allowed me to consume only about 50 grams (g) of carbohydrates per day.

RELATED: 8 Steps Beginners Should Take Before Trying the Keto Diet

3 Days Into the Keto Diet, I Felt Like I Needed a Flu Shot

The first two days on the diet, I felt a little more tired than usual, but it wasn’t anything I couldn’t handle. After working out hard for a few months, there would be days where I would feel more fatigued than others. I started to feel like that every day. I also felt very strange eating as much butter and oil as I was. Butter in particular is something we have been told for decades is really bad for you, and mentally, it’s hard to change those habits. But getting the fat to protein ratio right is critical. If you eat too much protein, it can actually knock you out of ketosis.

The rules of the keto diet are pretty strict, but they were easy to understand and follow. Pretty quickly the weight loss kick-started again. Within a week, I was down under 160 lbs for the first time, and 154 lbs (junior middleweight) was in sight. But the diet was proving to be pretty grueling. By the third day, I thought I was actually sick. I felt awful. I couldn’t think straight. I felt even more tired than I did when I was overweight. Traffic had come to a standstill in my digestive system. At times, the thought of having more coconut oil made me feel sick to my stomach. That’s when I learned about the keto flu.

RELATED: Why Keto Can Cause Constipation and Diarrhea — and How to Deal

My Experience With the Keto Flu and Its Symptoms

The keto flu isn’t really a flu, though it feels like it. The symptoms that a person may feel when they begin the ketogenic diet mimic many of the symptoms of the common flu caused by the influenza virus. The fatigue is debilitating, as are the headaches. Nausea becomes a constant companion that won’t go away.

This Is Your Body on Ketosis: Constipation and Other Keto Flu Symptoms

As your body makes the transition from using carbohydrates for energy to burning fat for fuel, it goes through some adjustments that can lead to various new symptoms, which usually subside in a couple of weeks. Not everyone experiences keto flu symptoms on the diet. Unfortunately, I seemed to have collected most of the symptoms — headaches, mental fog, nausea, constipation. People experiencing keto flu often have difficulty sleeping as well. (I’m not a particularly great sleeper, so there wasn’t any way of knowing if this was an issue for me.)

Faced with all of these new ailments, I contacted Cynthia Sass, RD, who splits her time between Los Angeles and New York City.

Sass has worked with professional athletes at the highest level, including members of the New York Yankees and Brooklyn Nets. As many pro athletes have at least experimented with the ketogenic diet, I explained my symptoms to her and asked for her advice.

Mental Fog Within about three days on the diet, my brain felt slower, like it had just run a race and wanted to sit down. It felt as if I was living underwater all day. I just didn’t have the same ability to process things as quickly as I used to. I couldn’t concentrate on the simplest tasks. Focusing on tasks at work seemed like it required an exhausting amount of effort. For a writer, it’s an occupational hazard not to be able to organize your thoughts. Even passively reading something for fun felt like a chore.

“Despite accounting for only 2 percent of adult body weight, the human brain uses 25 percent of the body’s total glucose at rest,” says Sass, referring to the body’s energy source created from carbohydrates. “These symptoms aren’t uncommon as the brain is forced to adapt to a new fuel source. I don’t think there is any way around the mental fog, as it just takes time for the brain to adjust.” But every day that it took to adjust, I was less and less productive at work. Articles that might take a day to write started to take three days. Professionally, I wasn’t sure how long I could continue to feel this way.

RELATED: The 11 Biggest Keto Diet Dangers You Need to Know

Headaches I would get really bad headaches in the back of my head and neck. They felt similar to the headaches I would get when I first tried to kick my caffeine habit. At its worst, I would have to lie down in a dark room for an hour or so until they subsided. Ibuprofen (Advil, Motrin) provided no relief. “The headaches may be due to a combination of the brain switching fuels, in addition to dehydration and electrolyte imbalances,” Sass says. “Drinking more water and consuming more electrolytes could help alleviate the headaches.” A small, low-carb sports drink, which offers electrolytes, should do the trick.

RELATED: 6 Unusual Signs of Dehydration You Should Know About

Occasional Nausea At first, I thought I felt nauseous because I wasn’t finding so much fat to be appetizing. To truly eat ketogenically, you have to limit yourself to about 50 g of carbohydrates per day. If you eat some fairly basic and very healthy foods like broccoli and bananas, you would be surprised how fast you can get to 50 g of carbs in a day. Three cups of broccoli with my meals for the day and a banana mixed with almond milk for a protein shake and I was pretty much at my daily limit of carbs. The rules are easy to follow on keto, but they are very unforgiving.

Adding the extra oils like olive oil and coconut oil intuitively didn’t feel right. In fact, it felt kind of gross. So I thought the nausea was a rebellion from the actual foods I had to eat. But it turns out, nausea is a fairly common side effect of the diet. “The nausea may also be due to dehydration and electrolyte imbalances,” Sass told me. “In addition, the enzymes that break down fat need to be ramped up to handle the higher fat load, and fats empty out of the stomach slower than carbs.” Sass advises considering plant-based fats that are healthier, like avocado and extra virgin olive oil, over animal-based fats, like butter, cream, and lard.

Constipation The keto diet definitely affected my body’s ability to get rid of waste. I would often go an entire day without using the toilet, and when I did, it wasn’t very productive. “This is very common, since a limit of 5 percent of calories from carbs doesn’t allow for much dietary fiber,” Sass said. “Eating fiber is like strength training for the muscles of the digestive tract. With a lower-fiber diet, the muscles aren’t stimulated as much, so they contract less, which means waste moves through the GI tract more slowly. For this, it would be wiser to eat smaller meals and spend your carbs on high-fiber vegetables.”

RELATED: The 10 Best Sources of Fiber on the Keto Diet

Weight Loss After 12 Days of Keto Dieting

On the keto diet, I made it down to my last goal weight of 154 lbs in just under two more weeks. While many may look at the results and say it was worth it, I didn’t feel that way at all. In boxing terms, I went from being a super heavyweight to a junior middleweight. And though I felt lighter on my feet, I also felt a lot weaker. At 168 lbs, I felt younger, energetic, as if I had a new life. People noticed the change and thought I had a new glow. On keto, I lost 14 additional pounds, but I felt like I was losing muscle. I felt weaker, older. It was as if I was willing my body to do something it didn’t want to do. I went from feeling like a superhero to feeling defeated.

So on the day I decided that being 154 lbs didn’t matter as much as feeling good, I cracked open a 32-ounce fruit punch Gatorade, the biggest bottle I could hold in one hand, and I drank it all in less than a minute. And it was delicious. It was like drinking a bottle of medicine. Within 30 minutes, I felt alive again. My energy level was back. It was as if someone turned on the headlights in my mind. The weight goals I had set were all arbitrary. The way I felt in this moment was real. I felt like myself again.

RELATED: The Possible Short- and Long-Term Effects of the Keto Diet

Reflecting on the Aftermath of the Keto Diet

The more I researched, the more I realized I could have it both ways. I could maintain a healthy weight while still having enough carbs to help me feel like my brain was functioning and my body was strong and energetic. I slowly started to add some more healthy, complex carbs back to my diet. In the evenings, I added a second protein shake with a banana, some crushed ice, and almond milk. It was like having a guilt-free dessert. I also started experimenting with adding a small cooled-down baked potato with my lunch and dinner. By cooling it, the potato contained more resistant starch, which helped with digestion without sending my blood sugar as sky high. This time I skipped the butter and just added a little salt. Removing all of the calories from the butter allowed me to eat more food and even have a small Gatorade after my workout and still stay within my calorie targets of about 2,600 calories a day.

RELATED: What’s the Difference Between Good and Bad Carbs?

Going on a more realistic diet that restricts my carbohydrates but doesn’t eliminate them entirely was the best dietary decision I made. I’m still able to eat portions of meat, chicken, and fish with vegetables that leave me feeling sated while keeping my calorie intake at the right level. For a snack, a few cubes of cheese or a handful of almonds is a perfect energy booster. Instead of thinking of it as food, I started thinking of it as fuel.

I also started time-restricting my meals. I eat my first meal of the day after I work out around 11 a.m., and I have my last food at around 8 p.m. The rest of the time, my body is fasting and continuing to use fat for fuel in addition to carbohydrates.

I’ve also listened to my body and added a lot more water to my diet. By staying hydrated, my body doesn’t hold on to water as much, and that helps keeps my weight down as well. Boxers know this well as they prepare to try to make weight for a fight. My new friends at the gym taught me well.

The biggest lesson I learned is that the keto diet may be right for some people, but it wasn’t right for me. The keto diet is great for people who like simple, straightforward choices on what to eat and do not experience any of the temporary flulike symptoms that come with following the diet to the letter. But by managing your carb intake more mindfully and incorporating a little more activity into your day, you can get to the same place. It’s not the destination; it’s the journey. And if you’re going to be on this journey for the rest of your life, you may as well enjoy each step.

Let me just start with a few disclaimers, because I know a few of you are already mad at me just based on the headline alone. I agreed to try the keto diet in early 2018 as a POPSUGAR editor experiment — not because I needed to for medical or weight-loss reasons. The goal was to see how my body felt switching from a moderate-carb diet to a very, very low-carb, high-fat diet (spoiler: not good). I had the right tools, including a clinical nutritionist versed in keto on speed dial and a program with recipes and lists of foods I could and could not eat.

When the plans were made, I had anticipated completing a 30-day program. I shopped at Whole Foods to get lamb and steak, refined my Bulletproof coffee recipe, and learned orders at local restaurants that were keto-approved just in case (hello, Chipotle).

Things fell apart for me pretty much immediately. Perhaps I’m a carb addict who needs a detox or perhaps this diet just wasn’t for me — but I started to feel unwell by the end of the first day. A series of headaches crept in, which apparently are common when you’re purging your body of carbohydrates. In this case, it’s called the keto flu . . . and I got the keto flu in the worst way. My nutrition coach advised eating green apples and drinking lots of tea, as well as adding in fresh herbs to my meals. This was supposed to mitigate the keto flu, so I followed the advice.


A day later, despite taking those steps, the headaches were worsening. I was so, so tired and couldn’t focus on work (hello, brain fog); my coworkers even noticed how unproductive I was (embarrassing). All I wanted to do was sleep! But I knew it was “normal” and that keto flu would soon fade, so I pressed on. I felt like a keto warrior and figured I just had to break through to the other side, right?

Wrong. I was not a keto warrior, but rather a keto disaster.

Days three through five consisted of an unending headache, all culminating in an 18-hour migraine finale; needless to say, I hit the carbohydrate-packed panic button real quick at that point. I decided the experiment and diet trial weren’t worth the pain I went through with keto flu — I didn’t want to lose weight, and I didn’t need the ketogenic diet to treat any medical condition. So yeah, I gave up.

I inhaled ate a bagel on the morning of day six, and it felt like a wave of relief crashed over me. Best bagel of my life.

After I resumed eating my usual carb-infused yet balanced diet, I was a bit worried that I’d “balloon,” as many people do after trying keto temporarily. ‘Twas not the case, friends. The only thing that I got after adding carbs back in was migraine relief. Sweet, sweet migraine relief.

So yeah. I tried; I failed. Some people thrive on this diet — I’ve seen it firsthand! But remember that no one diet is perfect for every single person’s body. Listen to your body, and work with a doctor and nutritionist or dietitian you trust to make sure you’re not putting yourself through hell for no reason. And yes, I think a life without carbs is my own personal hell.

Image Source: POPSUGAR Photography / Nicole Perry

If you’re following me on Instagram, you are already aware of my decision to transition out of the Ketogenic lifestyle and into a more generalized, “healthy” eating plan that would probably be best categorized as flexible dieting. This is not to say that keto is bad, I just knew from the beginning that it was not going to be something I could sustain long-term, and I was honestly too afraid of carbs to make the official switch to allowing them back into my diet.

First, let me list some things about Keto that has benefited me personally. These obviously do not apply to everyone, but these are some benefits that I found to this lifestyle:

  • Weight Loss – This is probably why a large portion of people choose to try the keto diet. It helped me lose weight, and I can’t deny that there’s definitely something about carbohydrates that can have a huge impact on weight.
  • Less Processed Foods – Seeing the carb counts on tons of foods made me realize fairly early on that I was going to have to prep the majority of my meals, which also meant creating dishes from scratch. I enjoy cooking, so it didn’t bother me, and it kept me from picking up too many things in the center of the grocery store where most of the processed foods are.
  • Math & Cooking Skills – As me before I started keto how many teaspoons in a cup and I couldn’t give you the answer without looking it up. I perfected the art of weighing, measuring, and dividing food and really learned what a legitimate portion should look like. P.S – There are 48 teaspoons in a cup (3 TSP in a TBS; 16 TBS in a Cup; so 3×16=48).

Now you’re probably wondering, well if there’s so many benefits, then why did you quit? Well, without further ado, here’s why I quit keto:

1. I Became Obsessed With Numbers – It’s one thing to weigh and measure and divide foods, but it becomes an extreme when you find yourself meticulously shaving off slivers of food because it was ONE GRAM over the serving amount. Tracking macros became a huge obsession and I found myself distracted by the numbers rather than enjoying the food I worked so hard to prepare.

2. My Weight Loss Stalled – This goes in part with #1 because the number on the scale is another number I became obsessed with. Watching the weight fluctuate but never budging out of my plateau range of 3-5lbs stressed me out and I forgot how to be proud of the 70lbs I had lost before that and got so worried about losing a few more.

3. Fruit – I personally believe that a “diet” that encourages you to eat salami with cheese as a snack over a banana or peach has some faults. I love fruit, and don’t think there’s anything to be afraid of when eating them, but it gets to a point in keto where someone learns that a 30g Carb banana is a huge no-no but a 0g Carb serving of cheddar is A-OK and it could lead to the same kind of obsession that I found myself to have.

4. Nagging Thoughts – Sure, fat keeps you satiated. But I never went a meal without thinking about my next one. I was always planning my meals, recipes, and was avoiding going out to eat because I knew I was limited to eating meat & veggies when everyone else was going to dig into a pizza or burger (which I believe is fine in moderation)! I never. stopped. thinking. about. food.

5. Restriction Lead to Binges – I binged. A lot. Technically my “keto” lifestyle was more carb cycling, because I allowed myself one cheat meal a week in order to satisfy any cravings and just let myself live once in a while. Some weeks I could get right back on track, but other weeks I couldn’t control myself and my cheat meal would lead to a 3-hour long snack fest of me “just tasting” things here and there until I felt sick and guilty about what I had done to myself. It was psychologically draining.

6. Keto Flu – I have a post titled ‘How to Avoid the Keto Flu’ so you wouldn’t think this would be an issue for me, since I successfully avoided it for the entire first year of being keto. But something must have changed in my body this year (age, maybe?) and I couldn’t get into the rhythm. I wouldn’t say I showed many of the common symptoms of the Keto Flu, but something was happening and I knew I had to stop. I was sluggish, my workout recovery was completely absent, I was tired, physically exhausted, and I knew it was because of the lack of carbs because I cracked into one of those skinny straws of honey they sell at markets and within 5 minutes of eating it I was perky, alert, and my body felt SO MUCH BETTER. Thanks to just the four measly grams of sugar I just sucked into my body.

Is it possible that the keto diet doesn’t work for some people?

Is it possible that the keto diet doesn’t work for some? What to do if you experience loss of motivation and returning depression when trying to follow a keto diet? Should you be concerned about high levels of ketones? And how many calories and carbs should you eat?

Get the answers to these and other questions in this week’s Q&A with me:

Loss of motivation and depression has returned

My name is Andrea and I’m 56. My parents and I have been doing keto since end of August 2018. It was great to get the mental clarity, all lost weight. Mum is no longer diabetic. Don’t want to go back to carbs at all. BUT for several months I no longer have the mental clarity I so enjoyed and I also have depression again. Got off my medication fairly quickly initially. Don’t have a regular GP at moment since our remote surgery hasn’t got a permanent replacement yet and don’t feel comfortable talking to the two that are currently there.

I’m really struggling with this dilemma since I wake up easily enough but the deep depressive thoughts are there straight away, and I can’t get rid of them and I struggle to get motivated.

I am very hesitant to go back on medication because of the unpleasant side effects.

Any suggestions?

Hi Andrea. I am sorry to hear that your depression symptoms have returned. Depression can be a challenge to remedy long term for some. But the fact that it got better initially and then relapsed makes me wonder if you were in ketosis at first and are not any longer. You may want to check your ketone levels and use a nutrient tracker to make sure you are below 20 net carbs per day and getting adequate protein as well. Plus, remember that many non-food related factors impact our mood, such as sleep, stress management, social connections, exercise, time in nature and more.

Last, and perhaps most importantly, sometimes people benefit from anti-depression medications in addition to lifestyle changes. I usually encourage people to have a regular relationship with a primary care doctor who can help manage that. You could look for one on our find a doctor page.

Also, you may want to visit our detailed guide on mental health and low carb.
Best of luck!

Bret Scher

Levels of ketones

Hello doctor, and thanks for your help in advance.

I have been eating low-carb, zero sugar, moderate protein and moderate-high fat for like 1-2 months and a half now. Also fasting 16, 24 or 36 hours, it depends on what I feel like.

I have lost 8 kg (18 lbs) and reduced my body fat percentage. So I am now super heathy, normal BMI, normal subcutaneous fat, etc. (I was just a bit chubby, never obese, never diabetic).

The thing is… sometimes I measure my ketones and they are a bit high (7-8 max when fasting) and I get a little nervous and worried about the ketoacidosis.

I don’t know if it’s something that I should worry about or not, but as I am a bit of a hypochondriac… you know. I’d rather ask. Should I worry?


Hi Ortiz. That is a very high ketone level that sometime can be present with ketoacidosis. The key differentiator is that ketoacidosis also has a low blood pH. This can be tested with a blood test. In addition, people usually feel tired, nauseated, or have rapid breathing when in ketoacidosis.

That being said, I agree that those ketone levels are high. You may want to keep your fasts shorter or try a reduced-calorie “fasting mimicking diet” instead. Of course, if at any time you feel unwell with ketone levels that high, you should seek immediate medical attention.

Here is a post we have about ketosis vs ketoacidosis that may help.

Bret Scher

Is it possible that the keto diet doesn’t work for some poor guys (just like me)?

I’ve been eating a strict keto diet (no dairy, almost no nuts and intermittent fasting) for five weeks without losing weight, but experiencing almost all the side effects (the constipation more than several days even after taking the pills, terrible ketone rash, the acne which I never had before…), but after checking every possible reason and still have so many terrible side effects (the rash and the constipation with the bloated stomach truly drives me mad to some degree even though I do enjoy the food), I just wonder maybe it’s just not suitable for me (like I’m genetically unable to digest so much fat) that I have to quit…

Anyway, thanks a lot for all the information and the wide knowledge!

Hi Emeline. I am sorry to hear you are experiencing those side effects. For most people they will go away within a couple weeks, especially with adequate hydrate and electrolyte supplementation. For some, however, the symptoms may last longer. Although the keto diet is an effective tool for most people who try it, there are some who may not do as well. For those people, and you may be one of them, we usually recommend a low-carb rather than a keto diet. Low-carb can mean anything less than 100 grams per day, but you want to try 50 grams to start. Just make sure you stick to high-quality, minimally processed carbs. That will hopefully relieve the side effects you are experiencing while still giving you benefits of relative carb restriction and overall health gains.

Bret Scher

Carb amount and calorie amount

Concerned after six weeks of keto that two things may need tweaking:

  1. How many carbs per day should be my goal?
  2. Do the amount of calories matter as long as my macros are in tolerance?


Hi John. Good questions. In short, YES! Calories still matter even if you hit your macro targets. Remember, to lose weight, we want to burn our own fat stores for fuel. If we have a surplus of calories coming in, even if they are fat calories, we will burn those first before tapping into our fat stores. That is why we recommend dietary fat as a “lever” or a tool to adjust up or down as needed for satiety and weight loss.

As for your carb goal, that may differ depending on underlying carb tolerance and activity level, but staying below 20 g net carbs per day will usually ensure that you remain in ketosis, You can always experiment with increasing that number (as long as they remain high-quality, minimally processed carbs) to find your personal threshold. Just pay close attention to your metrics and go back down to 20 or less if you have any setbacks.

Bret Scher


Keto for beginners

Intermittent fasting for beginners

How to lose weight

More questions and answers

Many more questions and answers:

Low-carb Q&A

Is your ketogenic diet not working how you thought it would? It’s a frustrating feeling, for sure — you’ve been following the rules, cutting the carbs, and you’re still not getting into ketosis or seeing any weight loss (if that’s your goal). You might be asking yourself, “Does keto work?”

The answer is yes, but you might be missing some key details that are sabotaging your efforts. If keto isn’t working for you so far, take a look at the most common reasons you might be stuck and what you can do to fix the issues.

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1. Not Tracking Carbohydrates

On the ketogenic diet, you want to follow the macronutrient ratio of low carb, adequate-protein, and high fat. It might seem obvious, but one of the most significant rules of keto success is to track your carb intake because hidden carbs can slip in unnoticed.

Carbs are everywhere. As much as you might try to avoid them altogether, that’s just not possible. Although carbs generally make up 5% of your diet on keto, the exact amount of how much you can tolerate and still stay in a state of ketosis varies a bit from person to person.

Factors that can affect how your body uses carbs include:

  • The types of carbs you eat
  • Your overall lifestyle
  • Your metabolic history

It’s a good idea to use a handy tracker and input what you eat to watch your carb amounts — at least for the short-term — so you can see how you react to different foods.

Avoid spiking your blood sugar with the carbs you eat. High blood glucose will kick you out of ketosis and slow down your fat loss very quickly.

Apps are perfect because you can carry them with you anywhere, such as the popular MyFitnessPal. This will help you see exactly how many calories and carbs you’re eating, which will help you mentally monitor everyday foods you eat.

Perfect Keto offers a free macro calculator that can also help you stay on track.

2. Not Eating Enough Calories

If you’re trying to lose weight, you might think that eating too few calories won’t be a problem for you. But when you cut out carbs and also have to stick to moderate protein, it’s easy to end up not eating enough calories from fat.

Plus, most Americans grew up falsely learning that fat, especially saturated fat, was bad for your health. If you’re still holding onto that belief, you might struggle to eat enough calories from fat each day. Remember, on the keto diet your main fuel source is fat.

Not consuming enough calories can be detrimental over time. Chronically low calorie intake can put your body in starvation mode, which means it’ll hold onto stored body fat. It can also negatively affect your hormones and other functions of your body, especially in women.

Track Your Calories

As with protein and carbs, track your calories to get a good sense of how many you need and how much you’re eating each day. (See a pattern here?) Again, MyFitnessPal is a good option.

3. Not Testing Blood Ketone Levels

Does keto work? It won’t if you’re not tracking your ketone levels to make sure you’re genuinely entering and staying in ketosis after your meals.

There are three different ways to test ketone levels in your body, but blood testing is best for the highest accuracy. You can get a specific reading at any time and see how ketone levels might change before or after meals or anything else you do during the day.

Test consistently so you can see exactly how what you eat (and even how you exercise) affects your levels of ketones.

4. Not Considering Nutrition

A lot of people only think about the high-fat and low-carb aspects of the keto meal plan. But that doesn’t mean it’s a free-for-all to throw nutrition out the window.

If you want to get the best results, you’ve got to think about the types of foods you’re eating too. This means high-quality fats and proteins — and lots of vegetables — to give you a nutrient-dense plate of food at every meal.

Eat High-Quality Fats

Sure, you might get into ketosis with low-quality foods as long as your macros check out, but that’s not a healthy way to maintain a state of ketosis.

You could add quite a bit to your toxic load if you fill your diet plan with conventionally farmed meats, dairy, and animal fats. You’ll end up paying for it long-term, and you’ll likely feel pretty exhausted by it.

Healthy, high-quality fats are essential for proper brain function, hormone creation, and other bodily functions. Since fat content is now 70-80% of your whole diet, you want it to be high-quality, including:

  • Fatty, grass-fed meats
  • Avocado
  • Cold-pressed unrefined oils (especially organic coconut oil, MCT oil, olive oil, and avocado oil)
  • Wild-caught fish (those omega-3s are key)
  • Nuts (ideally organic here as well)
  • Whole, organic olives

If you’re eating a lot of processed foods like bacon, packaged sausages, and cheese products, it’s time to switch those out for whole foods like the ones above.

Eat Micronutrients

You might be afraid to eat too many veggies since some of them can have lots of carbs. This is understandable, but those micronutrients are still important for your overall health. Here are some ideas for keeping your meals nutrient-dense while still keeping your net carbs low:

  • Focus on low-carb vegetables (leafy greens of all kinds are excellent options), and include healthy fat when you eat them. This will keep the proportion of fat high in your meal while also giving you a good boost of veggies. Plus, fat helps with nutrient absorption, especially fat-soluble vitamins.
  • Eat your veggies steamed. They’ll shrink down, which allows you to eat a lot at once.
  • Make a fat-centric smoothie that includes vegetables like kale and spinach.
  • If you’re still concerned about the carbs from too many veggies, make sure you’re also eating nutrient-dense animal products like organ meats.

Eat Fiber

Fiber is incredibly important for gut health and for moving things along comfortably. If you’re not eating vegetables, you might be lacking in this area. Use the advice above to get more veggies into your diet, and don’t forget to have them with a high-quality fat source.

There’s a chance you may need to proactively add a fiber source to your eating plan, like flax meal, chia seeds, or psyllium husk to keep your gut happy and avoid side effects like diarrhea. These work great in smoothies, keto-friendly oatmeal, and baked goods.

Include Fermented Foods

Fermented foods are another way to make sure your health and digestion are chugging along properly. If you’re new to fermented foods, start experimenting with different types and try to have two to three servings each day.

These could be:

  • Full-fat yogurt or kefir
  • Raw pickles (no sugar added)
  • Kimchi
  • Raw sauerkraut

Make sure to check the full ketogenic diet food list to see which foods are best to include in your high-fat diet.

Does Keto Work? It Does When You Work It Properly

If you’ve been on keto for a while and are finding yourself wondering, “Does keto work?”, there are a lot of possibilities for where things might be going sideways. Of course, it can be frustrating, but start with this list of suggestions to troubleshoot the problem.

Remember to track your carbohydrates and protein intake, test your ketone levels to see how your meals affect those levels, and know what you’re actually consuming to reap all the health benefits this diet has to offer. Use the points above to help you navigate through areas you might need to adjust, and you’ll be golden (and ketogenic) in no time.

Why Try the Keto Diet? Here Are 6 Very, Very Different Experiences

Some diets are highly scientific. All are highly personal.

Just because a method is trending on Instagram or showing up on the New York Times best-seller list doesn’t necessarily mean it’s right for everyone. Finding a diet that fits your lifestyle and helps you feel your best can require some exploration.

Research is a good first step in determining whether a diet might fit your needs. But in some cases, firsthand accounts can be more telling. Read on for six very different experiences with the keto diet.

“Keto was a life changing diet for me”

Liz, 34, homemaker

Why did you start keto?

I was overweight and wanted to lose weight, like most people. I was also having issues with high blood pressure and didn’t want to be on medication forever.

A friend told me about the keto diet, and it looked like the few things I wanted to change in my life, it could do. So I figured that before going to a doctor and going on medication, I should give the diet a chance.

How long did you follow the diet?

Three and a half years — eating keto is still my primary way of eating.

What works for you?

These days I can get by with eating extra carbs and still stay in ketosis. I eat closer to 30 net carbs, but starting out at 15 carbs worked well for me.

What hasn’t worked?

Overeating on fat and calories, which I found was fairly easy for me to do.

Did you experience any side effects?

I had major keto flu issues starting out. I’ve since learned how to avoid it, but when I began 3 years ago, resources and info were lacking.

What do you wish you’d known in the beginning?

There’s a lot of keto junk out there, so buyer beware. Also, how to avoid keto flu. But I did what I felt was a good amount of research starting out, so I felt like I had a good idea of what to expect.

Favorite keto recipe

Egg roll in a bowl and wings. I also make a killer keto friendly pho with zoodles.

The bottom line

Keto was a life changing diet for me. It was something I really needed for my overall health — not just physical but mental as well. I heard someone say, “the best diet is the one you can stick to.” I’m a pretty firm believer in that.

“I wish I had more knowledge about diet culture”

Christal, 29 (25 when on keto), editor

Why did you start keto?

I thought I was fat and needed to be “fit” to be attractive. I discovered keto on r/reddit and was convinced it was the healthiest way to lose weight.

I also convinced myself that because my dad had diabetes, it would be a preventive lifestyle (despite my not being large or heavy in any way).

How long did you follow the diet?

Three months at first, and then 5 additional months.

What worked for you?

Making a spreadsheet and creating my own recipes so I was in charge of the portion size. I made a “what to eat each day and when” spreadsheet and set a timer to remind myself to eat snacks.

It was also a very cheap and efficient way to cook. After the initial hump, my sugar cravings dropped. Thanks to keto, I’m more aware of what’s in my food. Was it worth it? Meh.

What didn’t work for you?

I got really fit and skinny. I looked great, but it didn’t change anything other than my body, which I realized wasn’t a source of happiness for me.

I hated not being able to eat freely, and I had to explain to everyone over and over about this new “diet” I was trying while they looked at me like I was unhinged.

It would make sense if keto was a prescribed diet or if I had allergies, but I was being an unnecessary burden for no other reason than my own physical insecurities.

Did you experience any side effects?

I lost a cup size in my bra.

What do you wish you’d known in the beginning?

I wish I had more knowledge about diet culture and intuitive eating. I understand keto for people who have conditions, but for me — I’m someone who is perfectly average and normal, who can eat freely and just go to the gym twice a week and be fine.

I just did my yearly wellness check and I’m very healthy. I haven’t been on keto and I’ve been eating whatever I want (intuitively)!

Favorite keto recipe

I loved buying chicken thighs with skin and then taking the skin off to bake into chips with cheese on top. I’d also make Parmesan chips.

The bottom line

I can eat all of that without being on keto!

“It’s more complicated than that for a type 1 diabetic”

Nathan, 29, physical therapist assistant

Why did you start keto?

In hopes it would improve my health. I have type 1 diabetes.

How long did you follow the diet?

Six months.

What worked for you?

I found that I needed smaller insulin doses for my meals — at least initially.

What didn’t work for you?

My A1C (blood glucose average) score rose, and my bad cholesterol went up.

Did you experience any side effects?

Keto breath, and my LDL levels rose.

What do you wish you’d known in the beginning?

That the body can turn excess proteins into sugars if you have too much of them.

Favorite keto recipe

Lupini beans.

The bottom line

I filled my diet with too much protein, and my body was slow to convert the excess protein into sugars. This, in turn, raised my blood glucose levels higher than normal in an insidious way — I couldn’t easily detect the change or correct it.

I also didn’t focus enough on good fats and treated as a bit of an excuse to eat fatty meats that were high in bad cholesterol. Avoiding carbs was easy for me, but it’s more complicated than that for a type 1 diabetic.

“I feel better than I have in years”

Carrie, 30, computer programmer

Why did you start keto?

Partially for weight loss but mainly to help decrease chronic inflammation.

How long did you follow the diet?

One year (and counting).

What worked for you?

I was able to get off a medication that I used for chronic inflammation, and I reached my goal weight.

What didn’t work for you?

It’s difficult to find a satisfying variety of meals because I’m a vegetarian and have food allergies, but overall it’s worth it.

Did you experience any side effects?

Slight hair loss, but not significant enough for others to notice. I added a collagen booster to my protein shakes, and it helped.

What do you wish you’d known in the beginning?

It would’ve been nice to have a carb-manager app for counting macros when I first started. And I wish I’d had a better understanding about carbs being a daily limit, protein being a daily goal, and fat being something you consume until you feel full.

Favorite keto recipe

Fathead Dough recipes.

The bottom line

This “way of life” is not for everyone. It’s a very limiting diet, especially for a vegetarian, and it takes away the opportunity to eat at the majority of restaurants (although this is improving).

It works for me — I feel better than I have in years and have found some great meals that work for me. I still enjoy a cheat meal every once in a while, though.

“ feel like I have six-pack abs all day long”

Mandy, 32, editor

Why did you start keto?

I wanted to drop a little weight quickly to improve my speed for a marathon.

How long did you follow the diet?

I’m currently still on keto. So far I’ve made it 4 weeks out of my goal of 10 weeks.

What worked for you?

I immediately dropped a few pounds, even though it’s probably just from water retention.

What has impressed me the most is how great I feel. I generally eat a healthy diet and stay away from refined sugars and processed carbs, but even still, restricting my intake of carbs from fruit and protein powders has left me feeling amazing.

What didn’t work for you?

My VO2 max and energy totally crashed after the first week. I went from strong 20-mile training runs to feeling like I could barely run 3 miles. I was also super hangry. This subsided after the first 2 weeks.

Did you experience any side effects?

My endurance exercise really crashed for a while, and I’m still trying to recover as my body becomes more efficient at burning fat for fuel.

The “keto flu” also took me over the first week. I wasn’t exactly hungry, I just felt really lethargic, short-tempered, and had a lot of brain fog, making it hard to concentrate.

What do you wish you’d known in the beginning?

That endurance running and high impact interval training would be pretty much a no-go for a few weeks.

Favorite keto recipe

Keto porridge. It consists of almond flour, flaxseed meal, an egg, a little bit of pumpkin purée, pumpkin spice seasoning, vanilla extract, and stevia. It helps me feel like I’m not totally missing out on PSL season.

The bottom line

It works. I’m dropping weight, don’t feel hungry anymore, and feel like I have six-pack abs all day long. My endurance still isn’t back to what it was, but that seems minor now compared to how great my stomach feels.

“here’s nothing magical about being in ketosis specifically”

Coleman, 30, product designer, author, and blogger

Why did you start keto?

I started keto out of a desire for performance — I’d heard from a number of places in the sort of “high performance tech bro” sphere (think Tim Ferriss, Dave Asprey) around the cognitive and energy management benefits of adopting a low or very low carb diet.

If folks like Asprey are to be believed, there’s some neurochemical magic to a brain that runs on ketones that promotes greater focus, more consistent energy, and the like.

How long did you follow the diet?

I decided I’d give it a month of strict keto (very low carb, moderate protein), using blood testing to keep myself at 1.0 millimoles per liter BHB or greater. It was fine.

While I didn’t feel much different cognitively, I did have more… ”even” energy throughout the day — no post-lunch slump, primarily — and if it weren’t for the strictness of the diet and the relative difficulty it caused for someone like me who travels a lot for work and therefore eats out quite a bit, I could have happily done it for a long time.

My base assumption after the initial month was that the “more consistent energy” thing was mostly happening because of lower and less spiky blood glucose. So, after the initial month, I began titrating my carbs up and keeping fiber high to see if it was ketosis or just low glycemic response that was making me better after meals.

Turns out, the ketones had nothing to do with it. Now, several years after that initial experiment, I still average something like 50 to 100 grams of net carbs a day, above the “keto optimal” zone but still pretty low carb as compared to the standard American diet.

What worked for you?

Even though it’s sometimes challenging to find food, a ketogenic diet does make food choice really easy. Does it have carbs? Don’t eat it. Otherwise, don’t worry about it.

If you’re also trying to keep protein below a certain threshold (necessary to get into deep nutritional ketosis without supplementing ketone powders or precursors like MCT oil), it gets harder. But broadly, simple rules make for easy adherence.

I also found that as someone who doesn’t have much of a sweet tooth anyway, I find fattier foods a lot more satisfying than leaner or even carby ones. The stuff I couldn’t have on this diet seemed like less of a loss than the inability to eat a steak .

What didn’t work for you?

I now understand why keto is an effective weight loss diet for a lot of people. Even if you’re eating as much bacon and cheese and all the rest as you can, it’s difficult to eat enough calories to maintain your body weight.

Did you experience any side effects?

I experienced the classic “keto flu” symptoms for a couple of days, but once I started consuming supplemental electrolytes (sodium, potassium, magnesium, zinc) and drinking extra water, I felt right as rain.

What do you wish you’d known in the beginning?

I did an absolutely excessive amount of research before trying it, so I went into it with pretty open eyes.

The only thing that I didn’t realize was how it would impact my perceived exertion for glycolytic-type exercise — circuits, sprints, and lifting. Even though my performance didn’t really suffer, it subjectively felt way, way harder.

Favorite keto recipe

Steak and eggs, cooked in butter. I never really believed in the “keto sweets” or “fat bomb” type stuff, because it always seemed like so much work for something that was supposed to be simple.

The bottom line

Even as a fairly active person, I don’t need nearly as many carbs as “standard” wisdom might dictate (and in fact feel better keeping this number fairly low).

And there are definite metabolic benefits to not being on a constant cycle of needing carbs every few hours (which is the same logic behind things like 16:8 intermittent fasting, the Zone diet, and so much more).

But at the same time, there’s nothing magical about being in ketosis, specifically.

I’ve done quite a bit of reading around the ketogenic diet for specific goals — for mitigating metabolism, for mitochondrial health, for epilepsy, as a way to make transitioning into fasting easier, etc. And I think it makes a lot of sense for people with those goals or conditions.

I also think it makes sense as a weight loss diet for people who have trouble with moderation (I would include myself in that group), because it’s so easy to understand what is and isn’t allowed.

Like strict Paleo and Whole 30 and any other number of effective but hard-to-sustain diets, it encourages insulin sensitivity and is strict, which makes it easy to follow but hard to get enough calories. Ketones are a byproduct of this, not a causal agent.

But as a regular guy who wants to perform a little better at the office and in the gym, I think it’s probably overkill.

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