What is ketosis?


How low carb is keto?

  1. The idea that fewer carbs is always more effective is mainly based on the consistent experience of experienced practitioners, and stories from people trying different levels of carb restriction

    The only intervention study – to our knowledge – that compared different levels of carb restriction was a small trial that found trends towards greater weight loss and greater improvements in cardiometabolic risk factors as carb intake went lower.

    PeerJ 2019: Low-carbohydrate diets differing in carbohydrate restriction improve cardiometabolic and anthropometric markers in healthy adults: a randomised clinical trial

    Ketogenic diets have been found to reduce appetite:

    Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis

    Obesity (Silver Spring) 2011: Change in food cravings, food preferences, and appetite during a low-carbohydrate and low-fat diet.

  2. Glycemic control appears to improve more the lower carb intake is:

    Journal of the American Dietetic Association 2008: Restricted-carbohydrate diets in patients with type 2 diabetes: a meta-analysis

    This is also based on the consistent experience of experienced practitioners, and stories from people trying different levels of carb restriction .

    Low-carb diets has been shown to help reduce or even normalize blood sugar, and thus potentially reverse type 2 diabetes:

    Diabetes Research and Clinical Practice 2018: Effect of dietary carbohydrate restriction on glycemic control in adults with diabetes: A systematic review and meta-analysis

    BMJ Open Diabetes Research and Care 2017: Systematic review and meta-analysis of dietary carbohydrate restriction in patients with type 2 diabetes

    A non-randomized trial with risk of financial bias shows remarkable effectiveness at reversing type 2 diabetes:

    Diabetes Therapy 2018: Effectiveness and safety of a novel care model for the management of type 2 diabetes at 1 year: An open-label, non-randomized, controlled study

    Full list of studies on low carb for diabetes ↩

  3. Diabetes Research and Clinical Practice 2018: Effect of dietary carbohydrate restriction on glycemic control in adults with diabetes: A systematic review and meta-analysis

    Annals of Internal Medicine 2014: Effects of low-carbohydrate and low-fat diets: a randomized trial

  4. Adults in the US consume about 50% of their calories from carbohydrates, or about 250 grams of carbs per day if eating 2000 calories:

    Centers for Disease Control and Prevention

  5. A diet under 20-50 grams of carbohydrates “typically leads to the presence of measurable ketones in the urine”:

    The American Journal of Clinical Nutrition 2007: Low-carbohydrate nutrition and metabolism

    Note that higher levels of carb intake also can be ketogenic in some people, depending on their metabolism and activity level (increased activity can contribute). ↩

  6. Carbs, fats and protein are sometimes called your “macros” — the percentage of the three macro nutrients. ↩

  7. The process of converting excess protein to glucose is called gluconeogenesis (literally “making new glucose”). During digestion, protein is broken down into individual amino acids, which your body can use to make glucose.

    International Journal for Vitamin and Nutrition Research 2011: Protein turnover, ureagenesis and gluconeogenesis ↩

  8. Diabetes Care 1991: Plasma glucose and insulin response to macronutrients in nondiabetic and NIDDM subjects ↩

  9. Gluconeogenesis is a demand-driven process that occurs whenever glucose is needed. For instance, when someone follows a carb-free diet, gluconeogenesis will provide glucose for the few parts of the body that can’t use ketones: red blood cells and portions of the kidney, eye and brain.

    American Journal of Clinical Nutrition 2009: Gluconeogenesis and energy expenditure after a high-protein, carbohydrate-free diet

    Very high protein intake on a keto or low-carb diet may also lead to gluconeogenesis.

    Diabetologia 2000: Effect of long-term dietary protein intake on glucose metabolism in humans

    However, reports from physicians who recommend a higher-protein, low-carb way of eating suggest that blood sugar response to this approach can vary quite a bit from person to person.

  10. Here are the exact protein limits we use to classify recipes as keto:

    4 % carbs = max 30 % protein
    3 % carbs = max 32 % protein
    2 % carbs = max 34 % protein
    1 % carbs = max 36 % protein
    0 % carbs = max 38 % protein

  11. Although some low-carb experts disagree, it’s generally accepted that humans lack the enzymes needed to break down fiber and absorb it into the bloodstream. Therefore, the fiber portion of carbs does not raise blood sugar and insulin levels.

    Nutrients 2010: Effects of dietary fiber and its components on metabolic health ↩

  12. Fiber does not directly affect blood sugar levels, though it can indirectly slow down the absorption of digestible carbohydrates that you eat.

    Fiber can have both beneficial and some potential negative effects on gut health, but it usually has no major impact on the effects of a low-carb diet. ↩

  13. For instance, maltitol – a very common sweetener in low-carb products – has the highest glycemic (35) and insulinemic (27) indexes of all sugar alcohols.

    Nutrition Research Reviews 2003: Health potential of polyols as sugar replacers, with emphasis on low glycaemic properties

    About 60% of maltitol is digested and absorbed in the small intestine, like other carbs.

    Gastroenterology 1990: Digestion and absorption in the human intestine of three sugar alcohols

    Gastroentérologie Clinique et Biologique 1991: Clinical tolerance, intestinal absorption, and energy value of four sugar alcohols taken on an empty stomach

  14. This is mainly based on evolutionary theories and clinical experience.

    Focus on eating good quality, minimally processed real food. Ideally the food you buy shouldn’t even have a list of ingredients (or it should be very short).

    Unprocessed real food is what our ancestors have been eating for millions of years, and what the human animal is evolutionarily adapted to. By introducing processing, e.g. refining carbohydrates in a way that increases the speed of absorption and reduces the amount of nutrients and fiber, we change the food into something our bodies may not be adapted to, i.e. we introduce an unknown risk of side effects.

    Learn more: What are you designed to eat? ↩

  15. This is mainly based on the consistent experience of experienced practitioners, and stories from people trying different levels of carb restriction

    The only small intervention study – to our knowledge – that compare different levels of carb restriction found trends towards a larger effects with fewer carbs, for weight loss and cardiometabolic risk factors. However, these trends did not reach statistical significance:

    PeerJ 2019: Low-carbohydrate diets differing in carbohydrate restriction improve cardiometabolic and anthropometric markers in healthy adults: a randomised clinical trial

    Regarding sugar/food addiction, this is likely mostly caused by avoiding the foods that can cause a food addiction, most of which are processed foods full of sugar and/or other refined carbohydrates.

    Just like with any other addiction, avoiding the cause is a necessary part of slowly reducing the addiction. A person who is addicted to alcohol normally can’t consume alcohol “in moderation” and be successful. The same thing is likely true for any addiction.

    In the case of the keto diet, it may also be that the hunger-reducing effect can be helpful:

    Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis

    Frontiers in Psychology 2015: Ketosis, ketogenic diet and food intake control: a complex relationship

  16. PeerJ 2019: Low-carbohydrate diets differing in carbohydrate restriction improve cardiometabolic and anthropometric markers in healthy adults: a randomised clinical trial ↩

  17. Unless there’s a specific reason for you not to do this.

    Who should NOT do a ketogenic diet? ↩

  18. It can also be helpful to experience it, as it’s a good way to shed a few pounds if weight ever creeps up or weight loss stalls. ↩

  19. Whether people go on a low-carb or a low-fat diet, they tend to lose weight as long as they minimize sugar and refined flours in their diet:

    JAMA 2018: Effect of low-fat vs low-carbohydrate diet on 12-month weight loss in overweight adults and the association with genotype pattern or insulin secretion (analysis)

    Here are more studies and overview articles showing a connection between sugar, excess weight and disease:

    JAMA Internal Medicine 2014: Added sugar intake and cardiovascular diseases mortality among US adults

    Nutrition & Metabolism 2005: Fructose, insulin resistance, and metabolic dyslipidemia

    The American Journal of Clinical Nutrition 2007: Potential role of sugar (fructose) in the epidemic of hypertension, obesity and the metabolic syndrome, diabetes, kidney disease, and cardiovascular disease

The keto diet is a high-fat, low-carb diet — but just how many grams of carbs per day is considered low enough?

Most people following a ketogenic diet will consume just 5-10% of calories from carbohydrates each day. If you’re eating 2,000 calories per day, this breaks down to 25–50 grams of carbs per day. (Don’t worry, you’ll dive into the math below).

This guide will help you determine how many grams of carbs per day to consume on keto. You’ll also learn how these amounts translate into various food sources (both good and bad).

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But before you go any further, here’s one thing you should understand: Every human body is different. While 30 grams of carbs per day is a good rule of thumb for most people, the truth is that age, activity level, weight loss goals, and body composition play a role in determining how many carbs you can consume and stay in ketosis.

How to Calculate How Many Grams of Carbs Per Day

Knowing how many grams of carbs to eat per day on keto can be tough. Why? Because keto goes directly against the teachings of the Standard American Diet. In fact, the USDA and most dietitians advocate for a high-carb, low-fat diet to prevent weight gain, suggesting that 45-65% of total calories should come from carbohydrates.

On keto, you’re trying to transition to a fat burning metabolic state where you burn ketones — rather than glucose — as your body’s primary energy source. To do this, you’ll need to eat large amounts of fat, switch to moderate protein intake, and keep your daily carb intake to an absolute minimum.

To enter (and remain) in ketosis, the macronutrient guidelines for the average person include:

  • 5-10% of calories from carbs
  • 20-25% from protein
  • 70-75%, or remaining calories from fat

The Difference Between Total Carbohydrates and Net Carbs

Here’s an important thing to note: On keto, you will always calculate your net carbs — not your total carbs — for the day.

Your net carb intake is equal to the total amount of carbs you consume (in grams), minus the grams of dietary fiber. Net carbs are calculated because dietary fiber does not raise your blood glucose levels (blood sugar) — which is exactly what you’re trying to avoid on keto.

Calculating Carbs By Hand

Unfortunately, knowing daily macro percentages isn’t too useful when you’re reading a nutrition label. To help calculate your macros (i.e. protein, fat, and carb intake), try translating these percentages into grams.

One gram of carbohydrates is equal to four calories, while one gram of protein and fat provides four and nine calories, respectively.

If you plan to consume 5% of your daily calories from carbohydrates, you would multiply 2,000 by .05, to get 100 calories per day. To translate into grams, divide 100 by 4, for 25 calories per day.

If your carbohydrate intake equals 10% of your daily calories, the same calculations would result in 50 grams of carbs per day.

Calculating Carbs Through the Keto Macro Calculator

The amount of carbohydrates you consume will be impacted by your age, activity level, and even bodyweight. To calculate how many macros you should consume, be sure to use the keto macro calculator for the most accurate results. Use the keto calculator to enter your information and calculate your macros.

Your Keto Carb Limit: Which Carbs Are Best?

If you’re eating just 25-50 grams of carbs per day, you’ll want to make those carbs count.

Carbohydrates include sugar, starch, and dietary fiber. Carbohydrates are found in dairy products, grains such as bread, white rice, and quinoa, and starchy vegetables such as sweet potatoes as well as green, leafy vegetables.

Good Carbs vs. Bad Carbs: The Keto vs. SAD Debate

When it comes to good carbs and bad carbs, once again keto takes a different approach than most nutritionists. The Standard American Diet (SAD) encourages people to eat complex carbohydrates, such as those found in lentils, beans, brown rice, whole grains, and starchy vegetables.

They tell people to veer away from simple sugars (or “bad carbs”) found in white rice, white bread, and processed snack foods, as most of the nutrition has been stripped away.

Most foods considered “healthy carbs” by USDA dietetics are eliminated on keto, as they spike your insulin levels (thereby kicking you out of a ketogenic state).

A keto meal plan consists of carbs that rank low on the glycemic index — a tool measuring how much a particular food raises blood sugar levels.

On keto, you’ll consume whole foods that rank very low on the glycemic index (and have very low net carb counts), including green, leafy veggies, healthy fats like avocados, olive oil, and MCT oil, and high-quality protein.

What Does 30 Grams of Carbs Look Like?

As stated earlier, most keto dieters consume between 25-50 grams of carbs per day when following a 2,000-calorie diet. For most people, the average seems to be 30 grams of net carbs per day. But what does 30 grams of carbs actually look like?

Below, you’ll find examples of how to hit your 30 gram carb limit on keto — both in healthy and not-so-healthy ways.


On keto, always choose fruits that are low in sugar. This means selecting low-carb foods like berries and avocado (yes, it’s a fruit), and avoiding high-sugar fruits like apples, oranges, and bananas.

If you’re wondering why you should do this, simply look at the serving size of the fruits below. You’ll get more bang for your buck by eating handfuls of berries than you would from eating a small banana.


Serving: 1.45 cups
Fiber: 5g
Net carbs: 25g


Serving: 2.75 cups
Fiber: 5g
Net carbs: 25g


Serving: 1 medium banana (5.5 oz.)
Fiber: 3g
Net carbs: 27g


Serving: 14 oz.
Fiber: 8g
Net carbs: 22g


Serving: 7.5 oz.
Fiber: 7g
Net carbs: 23g


Serving: 2 medium grapefruits (1 cup)
Fiber: 4g
Net carbs: 26g


Serving: 28 oz.
Fiber: 8g
Net carbs: 22g


Keto-friendly vegetables include leafy green vegetables such as kale, lettuce, broccoli, and asparagus. Meanwhile, you’ll want to avoid starchy vegetables such as sweet potatoes, white potatoes, parsnips, and carrots.


Serving: 12 oz.
Fiber: 12g
Net carbs: 18g


Serving: 11 oz.
Fiber: 8g
Net carbs: 22g


Serving: 30 oz.
Fiber: 4g
Net carbs: 26g

Red onion

Serving: 8 oz.
Fiber: 4g
Net carbs: 26g

Red pepper

Serving: 33 oz.
Fiber: 11g
Net carbs: 19g


Serving: 35 oz.
Fiber: 10g
Net carbs: 20g

Cauliflower or broccoli

Serving: 5.75 cups (20.5 oz.)
Fiber: 14g
Net carbs: 16g

Sweet potato

Serving: 120g (4.28 oz.)
Fiber: 4g
Net carbs: 26g


Many times, a whole food will contain a mixture of fat, protein, and carbohydrates. It’s important to take note of foods not classified as carbs that still contain traces of carbs in them. These foods include nuts, seeds, vegetables, and dairy products.


Serving: 12.5 oz. (2 large avocados)
Fiber: 24g
Net carbs: 6g
Notes: Two of these have only 6 grams of non-fibrous carbs.


Serving: 8 oz.
Fiber: 16g
Net carbs: 14g


Serving: 7.5 oz.
Fiber: 14g
Net carbs: 16g
Notes: This serving also has 1500 calories – don’t ignore calories especially if your goal is weight loss.


Serving: 3.75 oz.
Fiber: 4g
Net carbs: 26g

Full-fat yogurt

Serving: 26 oz. (4 containers)
Fiber: 0g
Net carbs: 30g

Grains and Sugars

You won’t find any grains or empty sugars on a keto diet plan, mainly because they rank so high on the glycemic index. Below, you’ll see that grains, candy, soda, and other high-sugar foods will quickly eat up your carb intake for the day.

Whole wheat bread

Serving: 1.8 slices
Fiber: 6g
Net carbs: 24g

Starbucks coffee drink

Fiber: 0g
Net carbs: 30g

Odwalla juice smoothie

Fiber: 2g
Net carbs: 28g

Red Bull

Fiber: 0g
Net carbs: 30g
Notes: Four sips and you’re at your 30 grams per day quota


Fiber: 0g
Net carbs: 30g

Gluten-free tortilla chips

Serving: 42g (1.5 oz)
Fiber: 1g
Net carbs: 29g

Harvest Snaps snack

Serving: 42g (1.5 oz)
Fiber: 1g
Net carbs: 29g

Snickers candy bar

Fiber: 0g
Net carbs: 30g


Fiber: 0g
Net carbs: 30g


Fiber: 2g
Net carbs: 28g

Kind bar

Fiber: 2g
Net carbs: 28g

Gummy bears

Fiber: 0g
Net carbs: 28g

30 Grams of Carbs in an Infographic

Want a simple, free reminder to print off or save that shows you exactly what 30 grams of carbs looks like?

Pin this to Pinterest or save it to your desktop so you don’t go overboard with carbs on your ketogenic diet.

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How Many Grams of Carbs Varies According to Your Goals

On the keto diet, most people eat between 25-50 grams of carbs per day, or 5-10% of their total calories. This stands in stark contrast to the diet you grew up on, where you were told to eat high amounts of carbs, without too much protein or fat.

The exact amount of carbs you consume will depend on your body composition, activity level, and fat loss goals. However, using the Perfect Keto Macro Calculator is a great place to start.

On the keto diet, your goal is to burn ketone bodies — rather than glucose — for energy. To do this, you’ll eat a high-fat, low-carb diet. Keto foods include high-quality meat, nuts and seeds, plenty of healthy fats, and low-sugar fruits and vegetables. If you are looking to get started, be sure to visit the Perfect Keto recipe library for plenty of low-carb meal ideas.

The keto flu, other keto side effects, and how to cure them

The keto flu

Symptoms of the keto flu:

  • Fatigue
  • Headache
  • Irritability
  • Difficulty focusing (“brain fog”)
  • Lack of motivation
  • Dizziness
  • Sugar cravings
  • Nausea
  • Muscle cramps

The cause

The keto flu is caused by your body’s transition from burning sugar to burning fat for most of its energy needs.

Switching from a high-carb diet to a very-low-carb diet lowers insulin levels in your body. This is not only healthy but also one of the primary goals of a ketogenic diet. When insulin levels are very low, your liver begins converting fat into ketones, which most of your cells can use in place of glucose. When your body is mainly using ketones and fat for energy, you’re in a state of ketosis.

However, it takes your brain and other organs some time to adapt to using this new fuel. When your insulin levels drop, your body responds by excreting more sodium in the urine, along with water. Because of this, you’ll probably find yourself urinating a lot more often in the first week or so of a keto diet.

This change is responsible for some of the rapid – and usually very welcome! – weight loss that happens in the early stages of a keto diet. However, losing a lot of water and sodium is responsible for many of the unpleasant symptoms of keto flu.

It’s well known that response to the keto transition is very individual. Some people may feel fine or slightly tired for a day or two after starting keto. At the other extreme, there are those who develop symptoms that strongly impact their ability to function for several days.

However, the keto flu doesn’t have to be unbearable for anyone if the proper steps are taken to remedy it.

The cure for the keto flu

Symptoms of the keto flu usually disappear by themselves within a few days, as the body adapts. But rather than suffering needlessly during this time, why not address the cause and start feeling better right now? The first step is by far the most important, and it’s often all that’s needed.

1. Top tip: increase your salt and water intake

Since loss of salt and water is responsible for most keto flu issues, increasing your intake of both can help reduce your symptoms significantly and often eliminate them altogether.12

During the first few weeks of your keto lifestyle, whenever you develop a headache, lethargy, nausea, dizziness or other symptoms, drink a glass of water with half a teaspoon of salt stirred into it. This simple action may alleviate your keto flu symptoms within 15 to 30 minutes. Feel free to do this twice a day or more, if needed.

Or for a tasty alternative, drink consommé, bouillon, bone broth, chicken stock or beef stock — and stir in a spoonful of salted butter, if you like. Or, if you’re using low-sodium bone broth or stock, add a pinch or two of salt.

In addition, make sure you’re drinking enough water. The larger you are, the more water you’ll probably lose in the early stages of keto, and the more you’ll need to replace. A good rule of thumb is to drink a minimum of 3 liters of fluid every day during the first week of your keto diet.

This doesn’t mean you must drink 3-plus liters of plain water in addition to your other beverages. Although drinking plenty of water is important, coffee and tea will contribute toward your fluid intake as well.

Getting enough water, sodium and other electrolytes can also help with another issue people often experience in the early stages of a keto diet: constipation.

Learn more about electrolyte supplementation on a keto diet

2. More fat = fewer symptoms

Increasing salt and fluid intake usually resolves most of the keto flu side effects. However, if you continue feeling poorly after following those recommendations, try eating more fat.

Due to decades of misinformation about fat being unhealthy, fat phobia is common among people who come to low-carb ketogenic eating. However, if you sharply lower your carb intake without upping your fat consumption, your body will think it is starving. You will feel tired, hungry and miserable.

A well-balanced keto diet includes enough fat so that you are not hungry after a meal, can go for several hours without eating, and have ample energy. Make sure to increase your intake of fat at the start of your keto journey until your body adapts to using fat and ketones for most of its energy needs. Once you’re fat adapted, let your appetite guide you in cutting back on fat a bit until you reach the point where you can easily maintain the balance between hunger and satiety.

In short: When in doubt, add fat (mmm, butter). Or follow our keto recipes, which have enough fat in relation to carbs and protein.

3. Slower transition

Has adding more water, salt and fat not helped very much? Are you still feeling achy, tired and off? We recommend you try to endure it for a few more days until the symptoms pass. Research has shown that a very-low-carb diet is best for weight loss and metabolic issues like type 2 diabetes.3Keto flu symptoms are only temporary – they’ll be long gone when you are a fat burner.

You can, however, slow down the transition to ketogenic eating by consuming a few more carbs, such as following a more moderate low-carb diet that provides 20 to 50 grams of carbs a day.

Eating slightly more carbs may potentially slow down weight loss and mute rapid, dramatic health improvements, but it can still lead to better health, especially if you are cutting out sugar and processed foods. And keto flu will no longer be an issue. Once you’ve adapted to low-carb eating, feel free to try eating less than 20 grams of carbs again to see whether your body prefers this or slightly higher carb intake.

4. Take it easy with physical activity

Although many people find that their energy and stamina improve on a keto lifestyle, trying to do too much in the early stages can worsen keto flu symptoms. Well-known ketogenic researcher Dr. Steve Phinney has conducted studies in endurance athletes4 as well as obese individuals5 demonstrating that physical performance decreases during the first week of very-low-carb eating. Fortunately, his research also shows that by week 4, people typically perform better than before they started keto.

Walking, stretching, or doing gentle yoga or other mind-body exercise should be fine and may even help you feel better. But when your body is already under stress from trying to adapt to a new fuel system, don’t place an additional burden on it by attempting any type of strenuous workout. Take it easy for the first few weeks and then slowly increase your exercise intensity.

5. Don’t consciously restrict food intake

Some people find that they aren’t very hungry the first week of keto because they are nauseated or have a headache that reduces their appetite.

However, others may get pretty hungry and worry that they’re eating too many calories or too much protein to achieve the kind of fast weight loss they’ve heard about.

The Atkins diet begins with induction, its strictest phase that allows for maximum fat burning and getting into ketosis quickly. On this diet, as long as carbs are restricted to 20 or fewer grams per day, you can eat as much of the allowed foods you need to feel full.

It’s not a good idea to focus on calories or macronutrients when you’re trying to become keto adapted. Letting yourself get hungry or stressing about the amount of food you’re eating may actually make keto flu symptoms worse. Once you’re steadily in ketosis, your appetite will likely go down, and you’ll naturally end up eating less.6

Eat as much of the allowed foods as needed until you are no longer hungry, and have carb-free snacks like hard-boiled eggs available in case hunger strikes between meals. On the other hand, make sure to avoid getting overly full by eating slowly and paying attention to hunger and fullness signals.

Dr. Eric Westman’s tips

Learn more about getting the best results and the least side effects on a ketogenic diet from world renowned keto expert Dr. Eric Westman. His five-part video course is on our membership site (one month free trial).

In video #3/5, he discusses how best to avoid transition problems like keto flu.

11 Ketosis Symptoms and Signs – Be Sure You’re Doing Keto Correctly

Branko | October 28

As you already know, the keto diet is great for weight loss, getting rid of brain fog, decreasing your risk for heart disease, and setting yourself up for long-term health.

But how do you know if your keto diet is actually working?

It’s pretty simple: there are specific ketosis symptoms and signs of ketosis you’ll experience so you don’t have to stress if you’re doing the keto diet “right” or not.

And that’s what this article will cover – the 11 main signs of ketosis.

To get you started, here’s a quick video covering the 6 ketosis symptoms:

11 Signs of Ketosis

Here are 11 signs of ketosis. You can use these keto symptoms as a gauge to see if you’re in ketosis. Some of these can be thought of as ketosis side effects. Thankfully, the less pleasant ones are temporary.

1. Increased Thirst and A Dry Mouth

Many keto dieters report having a dry mouth and feeling a lot thirstier than usual. If that’s something you’re experiencing, don’t worry. It’s one of the most common signs of ketosis. That means your diet is working!

When you first go Keto, you’ll be excreting a lot of water – that’s one of the ketosis side effects, and it’s related to switching to a diet high in fat and protein, but low in carbs. And you’ll be losing a lot of electrolytes (like sodium, potassium, and magnesium) along with the water.

You’ll not only be losing more sodium than before, you’ll also be eating less sodium than before. And that’s because you’re giving up processed foods. Think about how salty a bag of chips is – most highly processed foods have a lot of sodium in them. And when you cut those foods out of your diet, you’re also cutting out your main source of sodium.

This combination causes a drop in your electrolyte levels and the amount of fluid in your body. So you start feeling thirsty!

Bottom Line:

If you’re feeling thirsty and your mouth is dry, that’s a good sign you’re in ketosis!

But it’s also important to do something about this symptom: so drink more water, consider adding salt to your meals and make sure you’re eating foods rich in electrolytes.

2. Lack of Appetite

Feeling less hungry is another commonly reported side effect of a successful ketogenic diet.

That’s because a ketogenic diet affects your hunger hormones in a way that significantly reduces your appetite (there’s a study with proof here).

As a result, one of the best Keto diet side effects is reduced hunger levels (have a look at this study).

“Many dieters complain that hunger sabotages their success,” explains Dr. Vincent M. Pedre, M.D. “Ghrelin is your hunger hormone that tells you to eat. Research shows ketogenic diets suppress ghrelin, keeping you fuller longer. That makes sense: When you’re eating sufficient dietary fat and calories, you’re unlikely to be hungry.”

Plus, most of us typically have weeks or even months worth of energy stored in our bodies as fats. Which means when you’re in ketosis and have a calorie deficit, your body starts using up this stored energy source, greatly reducing your feelings of hunger. (Read more about regaining energy)

Bottom Line:

If you find you aren’t hungry or are eating less often, you may be in ketosis.

3. Rapid Weight Loss

Rapid weight loss in the first week can be a good sign that you’ve reached ketosis.

When you’re in a ketogenic state, your body sheds stored carbs and excess water. And that means you’ll initially see a rapid drop in your weight.

Once the bloating and water weight is gone, you’ll still lose weight – but less dramatically. Your body will start to burn up excess body fat, and you’ll find yourself slimming down in a safe manner.

Bottom Line:

Rapid weight loss is a common keto diet side effect, as you drastically reduce your carb intake which gets rid of water weight.

4. Smelly Breath or “Keto Breath”

One of the less desirable ketosis side effects after first switching to Keto is having unpleasant-smelling breath.

This happens because your body is making ketones which it can’t use yet – it hasn’t become keto-adapted. And it expels some of these excess ketones via your breath, in particular, a type of ketone called acetone.

Don’t worry, keto breath goes away pretty quickly and if it bothers you or your loved ones, then try adding some mint leaves to your water or even a few drops of mint essential oil to your water. Brushing your teeth more often is another option.

Bottom Line:

Having bad breath is one of the most reliable signs of ketosis.

Although it will disappear naturally, you can take steps to minimize it in the meantime: many keto dieters brush their teeth several times a day, in the beginning, to keep their breath smelling fresh.

5. More Ketones in Your Blood

Measuring the level of ketones in your blood is a sure-fire way to tell if you’re in ketosis.

When you’re in ketosis, your body starts burning more fat for energy and relies less on carbohydrates/sugars. Ketones are made as a byproduct of the breakdown of fat, and that’s why the number of ketones in your blood will increase when you’re in ketosis.

You can measure your ketone levels by using a specialized blood-ketone meter. It measures the levels of beta-hydroxybutyrate (BHB) in your bloodstream – which is the primary ketone your body produces when you’re in ketosis.

Bottom Line:

The most accurate way to tell if you are in ketosis is using a blood ketone meter to test your ketone levels.

And if you want more information on what your ketone levels mean plus what levels you should be aiming for, have a look at our article on What Are The Optimal Ketone Levels For A Ketogenic Diet?

6. More Ketones in Your Breath or Urine

Measuring the levels of ketones in your urine can give you a ballpark estimate of whether you’re in ketosis or not. And the same goes for the ketone levels of your breath.

This study concluded that “breath acetone is as good a predictor of ketosis as is urinary acetoacetate.” These types of ketones are expelled as waste through your urine as well as your breath. Which means it’s possible to measure your ketone levels via breath testers and urine strips.

In fact, Dr. Michael R. Eades, M.D. notes, “If you are righteously following a low-carb diet – especially in the early days – you may produce enough ketones to register on a breathalyzer should you get stopped on suspicion of being drunk.”

The main benefit of breath ketone testing is that it’s noninvasive. For the urine test, you pee on a stick that changes colors depending on the levels of ketones detected. And for the breath test, you breathe into a meter that then gives you a reading of how much ketones are detected on your breath.

However, both of these method of testing can be less accurate and most people wanting to test ketones stick to the blood meter still.

Bottom Line:

You can measure your ketone levels by using urine strips or a breath analyzer to check if you’re in ketosis. However, both these tests are less accurate than the blood meters.

7. Increased Focus and Energy Over the Long-Term

Some Keto diet side effects are found most in people who stick to a ketogenic diet long-term. For example, long-term Keto dieters often report reduced brain fog, increased mental clarity and an improved ability to remain focused. Listen in as Dani Conway describes how to build your keto diet to maximize your results.

That’s because following a ketogenic diet stabilizes your blood sugar levels.

Registered Nurse Jami Cooley, RN says, “Ketones are able to generate greater amounts of energy per molecule than glucose. Therefore, the ketones create a much more sustainable energy source for the body and do not cause the blood sugar spikes that glucose causes.”

You’re no longer eating many carbs, so you don’t experience blood sugar spikes followed by crashes. And that’s great news for your brain!

But it takes time for your body to adapt to burning fat rather than carbs for fuel. So if you’ve just started your keto diet, you’ll have to be a little patient before you experience this particular ketosis symptom for yourself.

Bottom Line:

If you find you feel more clear-headed and your energy levels are more stable, it’s a good sign you are in ketosis.

8. Increased Fatigue or “Keto Flu” in the Short-Term

If you feel weak and fatigued when you first make the switch to keto, that can be a sign that your keto diet is working.

When your body first has to make the switch to burning fats instead of carbs, it can take anywhere from 7 to 30 days before it becomes fully adapted. And while it adjusts, you’ll experience one of the most well known keto diet side effects out there: the keto flu.

“Symptoms of the keto flu include cravings, fatigue, insomnia, irritability, muscle cramps, or nausea,” says Certified Health Coach Dr. Christina Tarantola, PharmD, CHC. “Depending on the symptoms, adding Himalayan sea salt to beverages or food, increasing fat, magnesium, and potassium, and staying hydrated, can all help. This tends to last about 1 week and varies with each person.”

The exact symptoms differ from person to person. Some people get slight headaches. Others find it hard to focus. Others feel tired. This is often called Keto Flu because it can feel like flu-like symptoms, and even though Keto flu feels uncomfortable, just remember that it’s only temporary.

Often many people give up before their body fully adjusts to burning fat, so it’s important you stay motivated and use our 6 Strategies for Curing Keto Flu to get through this initial stage so you can experience the full benefits of Keto. A ketone supplement can also make the transition to Keto much smoother.

Bottom Line:

Feelings of fatigue and low energy, are common during the initial stages of a keto diet. It’s a sign that things are on the right track and you’re entering ketosis.

And you’ll soon start to experience the opposite effect once your body becomes adapted to burning fat and running off ketones!

9. Drop in Performance over the Short-Term

This goes hand-in-hand with the keto flu, so a drop in performance can be a sign that things are moving in the right direction.

Naturally, a lack of energy or weakness will also lead to decreased physical performance during exercise. You’ll experience a drop in your athletic performance while your body adapts to its new fuel source.

However, after a few weeks, your performance during your workouts should return to normal as your body will start burning fat more efficiently. Want to try working out with kettle bells? You need to hear this.

Bottom Line:

Experiencing a short-term decrease in your athletic performance is a sign your body is adapting to ketosis. And you should be back to your normal performance levels after a few weeks!

10. Digestive Issues

A ketogenic diet can give you digestive issues while your body adapts to your new diet.

Constipation and diarrhea are common side-effects which early-stage keto dieters experience. And they’re a sign your body is adjusting to a higher fat intake.

Luckily, like many of the other negatives you may experience when first going keto, they’re only temporary. They’ll pass as your body adjusts to a higher fat intake and getting energy from different foods than before.

Registered Dietitian Lauren Popeck, RD, says, “Constipation and diarrhea can result in the beginning as the body adjusts to processing different proportions of food. Eating low-carb vegetables can help.”

If you want to decrease the digestive discomfort, then make the switch to a Keto diet slowly so that your body has time to adjust. Eating vegetables is still important as it helps you get sufficient fiber to help your digestive system stay healthy.

Check out this list of low carb veggies to see which you ones you should adding to your keto diet. And if you need a keto fiber supplement, then CoBionic Foundation is a comprehensive prebiotic fiber that can really help.

Bottom Line:

Digestive issues are common when your first make the switch to a ketogenic diet, and they should pass with time. They’re just another sign your body is adapting.

However, if you don’t see signs of improvement, it may be a good idea to check if intolerances to specific foods could be causing the problem. And increasing your fat intake gradually can help prevent digestive issues in the first place.

11. Insomnia

Insomnia is one of the most common ketosis symptoms.

Many keto dieters reporting waking up during the night and experiencing restlessness during sleep. This happens because you’re dropping most of the carbs from your diets, and carbs are known for making you feel sleepy (just think about how much you need a nap after a large plate of pasta).

Insomnia normally goes away after a few weeks. And many folks find that they sleep better than ever before after they’ve been on the diet for a month or so and their body has become keto-adapted.

Another common report for Keto dieters is that they often need less sleep than before! But this is a long-term benefit that you’ll need to wait a few weeks to experience.

Bottom Line:

Trouble sleeping is common in the early stages of a ketogenic diet. However, sleep usually improves after a few weeks.

Pinterest Image For 11 Ketosis Symptoms and Signs

Please pin the image below so that you and others can quickly and easily refer to the list and check if you’re in ketosis or not.

The Best Way To Tell If You’re in Ketosis

As you can tell from the list above, there are various signs of ketosis that indicate your body is producing ketones.

But at the end of the day, if you really want to make sure you’re in ketosis, then testing your ketone levels is the more accurate method.

Here’s a quick recap of the three main ways you can test for ketosis:

  • Urine test strips
  • Breath analyzers
  • Blood-ketone meters

The most accurate method is to use the blood-ketone meter. These meters will show you the current level of BHB ketones in your blood, with a high degree of accuracy. The method of testing is similar to blood glucose meters – you prick your finger and draw a drop of blood that you run through a test strip attached to a meter.

The disadvantage is that these meters and their test strips are a lot more expensive than the urine strips or breath analyzers. However, if accuracy is important to you, then a blood-ketone meter is the best choice.

If you want more info about testing for ketone levels or what your optimal ketone levels are, then check out this post here.

And for more specific information about testing ketones in urine (whether it’s worth it and how to do it), check out our post here.

Worried You’re Not in Ketosis?

If you’re not experiencing any of the ketosis side effects I listed above, you might be worried you’re not in ketosis.

Don’t be: it’s not the end of the world if you aren’t always in ketosis.

Because the truth is, it’s more important to focus on feeling great and losing excess weight. You don’t get too caught up in worrying if you have 3 mmol/L or 2.5 mmol/L of ketones in your blood. If you’re getting results and losing weight, then chalk it up to a win!

And if you need any clarification or help, don’t hesitate to post in our forum. We’re here to help.

Don’t stress too much about your ketone levels

The key takeaway I want to you to remember is this: while it’s good to know whether you’re in ketosis or not, you don’t need to get too fixated on your ketone levels it and stress yourself out about it.

Instead, focus on how you’re feeling and the results you’re seeing:

  • Did you start keto to help you lose weight? Then focus on that as your end goal – you can often accomplish it without getting high ketone levels.
  • Have your energy levels increased since starting keto? Are you feeling more focused and positive? Then your keto diet is going brilliantly, no matter what your ketone levels are.

As long as you’re reducing your carb intake, steering clear of processed junk foods, and filling your diet with a wide variety of nutrient-dense foods, you’ll be doing your body good.

And that will be reflected in the way you look and feel, whether you’re in ketosis or not!

How Many Carbs for Ketosis?

Ketosis is the goal of the keto diet. There are many ways to achieve this metabolic state but restricting carbs is the safest and most practical one. But now comes the question of how many carbs for ketosis?

There is a specific carb limit at which everyone can reach ketosis. It’s around 30 grams of net carbs per day. Stick to that limit, and you’ll reach ketosis within 3 days. However, most people respond differently to carbs, so their ketosis threshold can vary.

If you’d like to learn more about the amount of carbs needed to reach ketosis, read our article below. We also talk how to limit your carb intake and offer additional advice and knowledge on reaching ketosis.

Carbs and Ketosis

Your body normally runs on the metabolism of glucose. Glucose is a simple sugar that your body breaks down from carbs. It enters your body’s cells with the help of a hormone called insulin from where mitochondria use it for energy production.

As long as your body is getting a steady influx of glucose, it prefers using it for fuel. But in the absence of glucose, like during fasting or on a keto diet, your body makes a ‘metabolic shift’ from glucose metabolism to ketone metabolism. Ketones are molecules that serve as an alternative to glucose. They include the following three:

  • Acetoacetate
  • Beta-hydroxybutyrate
  • Acetone

The switch to ketone metabolism is characterized by a higher production of ketone bodies and enhanced fat oxidation. This change in metabolism functioning is called ketosis. It is the goal of the ketogenic diet. In ketosis, your body is burning fat to make ketones which boosts weight loss. But it also comes with many health benefits as well .

Ketosis Benefits

Besides weight loss, ketosis comes with a wide range of health benefits. Some of these benefits include the following:

  • Epilepsy Control – The ketogenic diet was originally designed to treat epilepsy as studies showed that ketones reduce seizures .
  • Brain Health – Ketones have a protective effect on the brain; that’s why they’re so helpful with seizures. Ketones reduce oxidative stress and improve mitochondrial functioning of the brain. And now, researchers are looking into the diet as a treatment for a wide range of brain conditions .
  • Increased Energy – Ketones are a more efficient energy source than glucose. They provide more energy per weight and they use up less oxygen when metabolized.
  • Lower Cancer Risk – Cancer cells can’t thrive on ketones. That’s why researchers are considering ketones and ketogenic diet as an adjuvant cancer therapy .
  • Reduced Inflammation – Ketones have an anti-inflammatory and antioxidant effect. Inflammation is the leading driver of many disease states and ketones help prevent this problem.

Keto dieters also report increased mental alertness and greater feelings of well-being. Ketosis can also improve metabolic conditions like diabetes and PCOS. However, this effect is more due to the absence of inflammatory carbs than the presence of ketones.

Most ketogenic diet guidelines recommend 40 – 60g per day . This amount also includes dietary fiber and the carbs included should have a low glycemic index (GI) of 50 and less. However, depending on the person, carbs can be limited to as little as 10 – 20g per day.

As you can see, carb intake on a keto diet is not strictly determined. Still, it needs to be low in order for you to reach ketosis. To make things a bit simpler, most keto dieters simply eat less than 50 grams of total carbs per day or 30g of net carbs per day. This golden rule seems to work well for everyone. Total carbs are all carbs in a food, including the fiber while net carbs are carbs minus the fiber.

However, if you’d like to adjust your keto carb limit to meet your specific needs and goals, we suggest using our Keto Calculator. It calculates your daily calorie expenditure and determines the amount of carbs you should eat based on your physique and activity levels.

Athletes and highly active people can eat a larger amount of carbs without being kicked out of ketosis. That’s because their muscles use up glycogen more quickly and in higher amounts than in sedentary folks. Athletes use something called “carb cycling” to stay in ketosis while following the keto diet. It involves periods of carb refeeding (up to 130g carbs) and periods of keto eating.

How to Eat for Ketosis

To meet your daily carb limit for ketosis, eating the right kind of carb foods helps. Keto guidelines lay out a few simple rules for you to follow that help you reach ketosis. Here is what those rules look like:

Stick to low-carb, low-GI foods

Low-carb foods include leafy greens, peppers, eggplants, cauliflower, and many others. These typically have less than 10 grams of net carbs per serving. They also happen to be low on the GI scale. The GI scale ranks food based on how they affect your blood glucose with the lowest rank being 0 (cheese) and highest 100 (pure glucose).

Avoid high-carb, high-GI foods

Of course, this rule really goes without saying. Nonetheless, we need to emphasize just how important excluding high-carb food on a keto diet is. High-carb foods include all grains, legumes, root vegetables, corn, most fruit, honey, sugar, and many other sweeteners.

Switch to Low-Carb Alternatives

For variety, keto dieters like to replace high-carb kitchen staples with their low or no-carb counterparts. Examples include using coconut, almond, and other nut flours instead of wheat flours. Coconut and almond milk are low-carb alternatives to dairy milk. Non-nutritive sweeteners like stevia and erythritol help you enjoy keto desserts without too many carbs.

And of course, you also need to eat plenty of fat on a keto diet to boost ketosis. Butter, sour cream, fatty cuts of meat, nuts, and olive oil all contain fatty acids your liver will use to make ketones. If you lower your calorie intake, your body also uses its own fat stores to make ketone bodies and this boosts weight loss. In case you want to learn more about what to eat on a keto diet, click on this article.

Protein Also Matters

While eating few carbs on keto is the single most important thing for ketosis, your protein intake also matters. Your body is able to convert several amino acids from protein-rich foods into glucose. This process is known as gluconeogenesis . It’s a metabolic pathway that prevents hypoglycemia on low-carb diets. However, it can also kick you out of ketosis when protein intake is too high.

But how much protein boosts gluconeogenesis. Well, a moderate intake of 1g per day per kg of body weight is safe on keto as long as you are eating enough fat (65-80% of your daily calories). Going above that is detrimental to ketosis and is the same as eating high-carb foods.

A moderate intake of protein is also important for health and functioning. Protein builds and repairs tissue. It’s also essential for the production of enzymes, hormones, and immune system cells. Proteins are essential nutrients your body simply can’t live without unlike carbs. That’s why excluding them from your diet is not only unnecessary, but dangerous.

Reaching Ketosis

Restricting carbs to below 50 grams per day, boosting fat intake to 80% of your daily calories, and being moderate with protein is a sure way to reach ketosis. Once you are in ketosis, your body has made the switch from sugar burning to fat burning. Here is how ketosis takes place in your body on a low-carb diet:

Phase I – Glycogen Depletion

In the first 1-3 days on a low-carb diet, your body turns to liver and muscle glycogen to increase blood sugar levels. Glycogen is the stored form of glucose and that your body uses up within just a few days of low-carb eating.

Phase II – Fat Oxidation

When glycogen stores are used up, your body is forced to turn to its fat stores for energy production. Some of these fats are used for energy while others are converted into ketones. The reason your body makes ketones is that some cells (e.g. brain cells) cannot run on fatty acids and need alternative sources of energy. However, if your fat intake is high enough, your body will be using dietary fat for ketone production instead of using its fat stores.

Phase III – Ketone Utilization

It takes time for your body to adjust to the changes in fuel availability. Some people take longer to adapt to the ketogenic diet, while others seem to make the switch effortlessly. But around 2-4 weeks is an average for most. When your body starts utilizing ketones and oxidizing fat for energy, you have officially become keto adapted.

In the process of reaching ketosis, you’ll also experience some side effects termed “keto flu.” It’s not a real flu and neither is it contagious. It’s simply a result of fluid and electrolyte loss from glycogen depletion. Glycogen is stored with lots of water. So, when your body uses up glycogen, it also uses up the water and electrolytes with it. The keto flu is easy to treat with fluid intake, electrolyte drinks, and rest.

Speeding up Ketosis

While you can expect ketosis within the first week of carb restriction, a week-long keto flu may not be something you want to bear. That’s why keto dieters and keto experts came up with ways to speed up ketosis safely and effectively. To speed up ketosis, you can do one of the following things:


Intense exercise depletes glycogen stores within hours . In comparison, it takes up to two days to completely deplete glycogen stores with moderate activity levels. Make sure to keep eating the recommended daily amount of carbs to keep your blood glucose levels stable.

Take MCT Oil

MCT is short for medium-chain triglycerides. These are types of fats that your body uses differently than any other fat. They don’t require enzymes or bile salts for digestion and instead get absorbed directly in the small intestine and transported to the liver. There, they’re used for immediate energy and ketone production .

Try Exogenous Ketones

Exogenous ketones are dietary supplements designed to enhance ketosis. These ketones are made in the laboratory and available in powder and pill form. Studies show they help put you into nutritional ketosis within hours . Keto dieters use these to shorten the keto flu and to correct dietary mistakes on keto.

Lower Your Carb Intake

The lower your carb intake, the faster you’ll get into ketosis. If you are relatively healthy, you don’t have diabetes or suffer from a kidney condition, then eating 10-20 grams of net carbs per day can safely put you into ketosis within 2-3 days. Also make sure you are eating lots of fat to get enough energy and boost ketone production.

Testing for Ketosis

Knowing when you are in ketosis will help you determine if you’re following the keto diet correctly and if you need to adjust your carb intake. There are several ways to do this:

Urine Test Strips

These are affordable and easy to use. Many keto-ers use them to test for ketosis throughout their keto journey. However, they may not be reliable beyond the first weeks of going keto. Your body initially excretes a large amount of ketones before being able to fully utilize them. As your body starts becoming keto-adapted, you can expect the amount of ketones released through urine to drop.

Keto Breath

A fruity-smelling breath is a sure sign you are in ketosis. Some also describe this breath as smelling of nail polish remover. It’s the result of the breakdown of ketone bodies and their byproduct (acetone) being released through the lungs.

Keto Flu

Feeling tired, achy, and nauseated in the initial days of a low-carb diet means your body is heading towards ketosis. It can take up to a week or two for your body to adapt to this change in metabolism, so these uncomfortable symptoms are only temporary.

Greater Energy

Once the keto flu is over, you can expect an increase in mental and physical energy. Ketones are a more efficient source of energy than carbs which contributes to greater energy. You’ll also have fewer hunger pangs and won’t rely on food all that much to feel energized.

Bottom Line

To get into ketosis, you need to eat around 50 grams of carbs per day and not more. However, if you are an athlete or highly active, you can increase your carb intake a little bit around workouts. Otherwise, stick to the first simple rule of keto eating and you won’t have to worry about getting into ketosis.

Besides knowing how many carbs are needed for ketosis, you also need to keep an eye on your fat and protein intake. Dietary fats help boost ketone production. Protein is essential for health but too much of it gets converted into glucose which is bad for ketosis.

To speed up ketosis, try MCT oil and exogenous ketones. You may also want to work out a bit to speed up this process. However, that’s really not necessary for ketosis and the choice is up to you. The bottom line with entering ketosis is restricting carbs. Everything else is a good addition that supports ketosis and keeps you in good health.

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Ketosis is a natural state the body finds itself in when it is using fat as its main fuel. This occurs when following a very low carb, ketogenic diet , and often during intermittent fasting too.

Ketosis can be beneficial for a number of people but there are certain groups, such as people with type 1 diabetes, that need to be more careful. In these groups, very high ketone levels would lead to diabetic ketoacidosis , a dangerous situation caused by a lack of sufficient insulin.

What is nutritional ketosis?

Ketosis is a state the body goes into if it needs to break down body fat for energy. The state is marked by raised levels of ketones in the blood which can be used by the body as fuel.

Ketones which are not used for fuel are excreted out of the body via the kidneys and the urine.

Is ketosis the same as ketoacidosis?

Nutritional ketosis occurs when there is not enough carbohydrate in the diet to meet the body’s energy requirements. In this situation, the body switches over from burning sugar to burning fat as its main fuel.

Fat, whether from the diet or the body’s stores, is broken down into ketones in the liver. These ketones are an efficient energy source for many organs, particularly the brain.

Everyone has ketones in their blood at very low levels, under normal conditions. When the body enters ketosis, and so switches to burning mostly fat, levels of ketones in the blood increase.

Groups at greater risk of ketoacidosis

Some people are at risk of ketoacidosis.

Groups at risk of ketoacidosis include, but is not limited to, people with:

  • Type 1 diabetes
  • Cystic fibrosis-related diabetes
  • Pancreatectomy
  • Type 2 diabetes with very little pancreatic function

It is possible, and can be beneficial, for people in these groups to follow a ketogenic lifestyle. However, it is important that your doctor is aware of your intention before you start.

Your health team can help you with regard to how best to monitor for ketones and prevent ketoacidosis occurring.

Ketosis vs ketoacidosis

Whereas ketosis is an important natural state allowing the body to run on fat for energy, diabetic ketoacidosis (DKA) is a dangerous and potentially fatal condition.

DKA occurs during situations of ‘internal starvation’ mainly in people with type 1 diabetes, when not enough insulin has been administered.

In this case, the body does not have enough insulin to allow blood glucose into cells. The body believes it is starving and so breaks down fat and protein into ketones at an alarming rate, far above what is seen in nutritional ketosis.

In most cases, ketoacidosis develops when there are both high ketone levels and high blood glucose.

Benefits of nutritional ketosis

In most people nutritional ketosis is beneficial.

Regularly achieving nutritional ketosis has been linked with improvements in:

  • Weight loss
  • Blood glucose control in diabetes
  • Epilepsy
  • Overall metabolic health

Research also suggests that nutritional ketosis may have benefits for people with Parkinson’s disease, Alzheimer’s disease and may help to reduce the chance of developing certain forms of cancer.

Measuring ketones

Ketone levels between 0.5 and 3 mmol/L are considered nutritional ketosis. Ketones are measurable in a number of ways, including blood monitors, breathalysers and urine testing strips. Of these, urine strips are the least effective, as they only measure the ketones that your body is getting rid of, and not the ones it’s using.

The graph below shows the range of blood ketone levels for ketosis and ketoacidosis.

Note that people at risk of ketoacidosis, such as people with type 1 diabetes, should interpret ketone levels in the way laid out by their diabetes health team.

From The Art and Science of Low Carbohydrate Performance by Jeff S Volek, PhD, RD and Stephen D Phinney, MD, PhD. (Page 91)

But a ketogenic diet takes the metabolic state of ketosis to the next level. People who follow a low-carb or keto diet to get into a more permanent state of ketosis report health benefits like mental clarity, weight loss, and better performance at the gym.

But what is ketosis, exactly? How does it work and is it safe? What about for the long-term? Learn all of that and more is this complete guide to ketosis.

What is Ketosis?

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Ketosis is the metabolic process of using fat as the primary source of energy instead of carbohydrates.

Carbohydrates fall into two categories:

  1. Starchy carbs from foods like bread, pasta, potatoes, and other high-carb vegetables
  2. Sugar from things like candy, cakes, pastries, and ice cream

Get a full list of carb-heavy foods here.

On a higher-carb diet (or a Standard American Diet), the body runs almost exclusively off of glucose. You have glucose in your blood and stored glucose (aka, glycogen) in your muscles and organs like your liver.

On a low-carb or ketogenic diet, dietary fat and fatty acids from stored body fat are released into your bloodstream. From here, your body can use these fatty acids as fuel or they get transformed into molecules called ketones.

Ketones are produced when liberated fatty acids (from dietary fat and broken-down body fat) make their way to the liver. In the liver, they’re oxidized and turned into ketones to provide energy for your body and brain.

Fatty acids make great fuel, but ketones are even more powerful. Your body uses them efficiently as fuel. And ketones can cross the blood-brain barrier to provide quick energy for your brain. But only in the absence of glucose.

Health Benefits of Ketosis

Ketosis is one of the best-studied diets in the nutrition sciences. Its effects on physical performance and brain health is especially impressive. And, of course, many people use the keto diet to lose unwanted body fat while maintaining muscle mass.

Here are just a few known benefits of the keto diet:

Weight Loss

Probably the most widely talked about use for ketosis right now is weight loss. Because you’re using fat as fuel, ketosis can help you burn through fat stores more quickly.

You may also shed more pounds while in ketosis because of its effects on blood sugar and insulin, cravings, and energy.

Blood Sugar Balance

Ketosis stabilizes blood sugar and helps prevent insulin resistance. Studies show that restricting your daily carbs may improve insulin sensitivity, obesity, and triglyceride levels. In one study, insulin levels in the ketogenic group decreased three times more than the low-fat dieters.

Keeping blood sugar and insulin stable won’t just stave off metabolic syndrome and type 2 diabetes; it may also result in fewer cravings.

Fewer Cravings

Another way ketosis helps you lose weight — you’ll have fewer cravings.

Research into low-carbohydrate diets vs. low-fat diets has shown that low-carb diets significantly reduce food cravings, where low-fat diets increase them.

With keto, you can stop relying on your willpower and self-control muscle and instead rely on balanced hormones and naturally fewer cravings.

Keto can also suppress your appetite so you’re more satisfied with smaller portions.

Better Brain Health

Ketones can cross the blood-brain barrier and provide clean mental energy without the crash that comes with carb-heavy meals.

Although glucose is the preferred form of energy for the body, a large part of your brain can also ketones as fuel for mental performance on a low-carb ketogenic diet. Plus, your body can provide internally-made glucose to the brain (through gluconeogenesis) during ketosis.

Ketosis has also been used to help control seizures in children with epilepsy. And it’s been shown to have benefits for people with degenerative brain diseases like Parkinson’s and Alzheimer’s.

Higher Athletic Performance

During long periods of exercise, the body uses both what you’ve recently eaten and stored glycogen to power you through. But when those glycogen stores have been used up and you still need fuel, the body must turn to protein or fat for more energy. This is not a very efficient process — unless the body has adapted to being in a ketogenic state.

When you’re in a ketogenic state, your body quickly converts dietary fat or stored fat into usable fatty acids or ketones for quick fuel.

Longevity and Disease Prevention

Ketosis has been shown to decrease inflammation, which is at the root of many chronic diseases, including many autoimmune diseases.

Blood glucose and insulin levels are directly related to brain health. So, it’s no wonder that many researchers are looking at ketosis as a treatment option for degenerative brain diseases like Alzheimer’s and dementia.

Ketosis can help balance blood sugar and make your cells more sensitive to insulin. Which is why many researchers are looking at a ketogenic as an alternative treatment for type 2 diabetes patients.

How to Get Into Ketosis

There’s only one real way to get into ketosis and that is to cut your carb consumption. The general carb limit for the keto diet is around 30 grams per day. If you’re an athlete, this may increase to 100 grams.

Of course, you’ll need to replace those calories from carbs with something else, and when it comes to a keto diet, that something else is protein and fat.

You’ll have a unique macronutrient ratio that works for your body and goals, but the general rule is:

  • Carbs: 5-10% of daily calories
  • Protein: 20-25% of daily calories
  • Fat: 70-80% of daily calories

Use this keto macro calculator to find the macros that work for you. Other than your macros, it just takes a little time to become fat-adapted. Fat-adaptation simply means that you’ve run through your stored glucose and your body is now used to running off of fatty acids and ketones.

Here’s how it works:

Step #1: Cut Carbs

When there isn’t a sufficient level of available glucose and glycogen levels are depleted, blood sugar and insulin levels decrease, and the body looks for an alternative source of fuel (fat).

Step #2: Your Body Breaks Down Fatty Acids

The body breaks down fats for energy. This process is known as beta-oxidation, where there is an increase in acetyl-CoA, which turns into acetoacetate. Acetoacetate then shifts to beta-hydroxybutyrate, the ketone body that floats around in your blood to then provide energy to the body and brain.

Step #3: Using Ketones

Your body and brain are able to use ketones as a quick and efficient source of fuel.

How Many Carbs For Ketosis?

The number of carbs you have to cut to get into ketosis varies from person to person. This depends heavily on:

  • How much fat you have to lose
  • Your activity level
  • Your metabolism

Many people have to cut down to 30 grams of carbs per day or fewer to start the fat-adaptation phase. Others — like athletes who burn a lot of energy throughout the day — can get away with more carbs, from 50-80 grams.

Again, use the keto macro calculator to determine your carb goals. If you’ve gone three to four weeks on a keto diet and you’re still not in ketosis, you may want to lower your carb intake even more.

If you’re super low on energy after the first week or so on a keto diet, you may want to add some carbs back in.

How Long Does It Take to Get Into Ketosis?

This transition could take anywhere from 48 hours to one week, depending upon your activity level, lifestyle, body type, and carbohydrate intake. It also depends on whether or not you’ve become fat adapted before.

Many people report being able to get back into ketosis quickly once they have been in ketosis prior.

There are several ways you can speed up this process, like intermittent fasting, drastically cutting your carb intake, trying a carnivore diet, or cutting carbs while upping your exercise routine to burn through stored glucose faster.

How to Get Into Ketosis in 24-Hours

The average person may enter a mild state of ketosis during an overnight fast. Fasting causes your blood sugar and insulin levels to drop. These metabolic changes signal your liver to turn fatty acids into ketones.

But that doesn’t mean that you’re fat-adapted or that you’ll get the benefits of ketosis overnight.

It’s highly unlikely you’ll get into a steady state of ketosis in 24 hours. Even more so if you’re doing a ketogenic diet for the first time. Your body has been burning sugar for fuel your entire life. It will need time to adapt to burning ketones for fuel.

And remember: Once you get into ketosis, there is no guarantee you will remain in ketosis. If you eat a carb-laden meal, practice carb cycling, or increase your carb intake for athletic performance, your body may start burning glucose again.

To get back into a fat-burning state, follow the same methods you did to get into ketosis initially.

How to Stay in Ketosis

Staying in ketosis is pretty simple. Just continue restricting carbohydrates and focusing on low-carb vegetables, high-quality protein, and healthy fats like grass-fed butter and coconut oil.

Other tips to stay in ketosis include:

  • Intermittent fasting
  • Make sure you’re not overeating calories
  • Commit to a fitness plan to keep your glycogen stores low

Check out these helpful tips to getting into and staying in ketosis.

How to Tell if You’re in Ketosis

You might be wondering, what does ketosis feel like? Do you have to test your ketone levels to know whether or not you’re in ketosis?

The first phase of ketosis is actually called the fat-adaptation phase or keto-adaptation phase.

This is when you’re making ketones, but your body isn’t 100% used to producing them or using them as fuel.

When you begin to produce ketones on a more regular basis, you’re fat-adapted. Your body has fully shifted over to burning fat as its primary fuel source, to the point where you have metabolic flexibility: you can eat carbs and fall out of ketosis, and your body will snap right back into keto once it processes the carbs. This may take a month or more.

During this adaptation phase, many people experience flu-like symptoms that include:

  • Brain fog
  • Dizziness or confusion
  • Nausea
  • Irritability
  • Diarrhea or constipation
  • Muscle cramping or soreness
  • Lack of concentration or focus
  • Trouble falling or staying asleep
  • Sugar cravings
  • Heart palpitations

These symptoms are temporary and should subside in a week or two.

Getting into ketosis — even on the keto diet — does not guarantee fat-adaptation. That’s why it’s important to stick to strict keto for at least a few weeks when you’re just starting out if you want all the biggest benefits of ketosis.

Once you’re fat-adapted and in ketosis — that’s when you can really tell you’re in ketosis.

What does Ketosis Feel Like?

Many people report feeling differently when they’re in ketosis. A few noticeable side effects of ketosis include:

  • More stable energy
  • Reduced cravings
  • Mental clarity
  • More endurance
  • Weight loss

Still not sure you’re in ketosis? You may want to test.

How to Measure Your Ketone Levels

A great way to be sure you’re in ketosis is by measuring the ketone levels in your body, and you can do this right from home.

When your body makes ketones, it won’t use all of them all as energy.

Excess ketones will spill into different areas of the body. There are three different ways you can measure ketone bodies: in your urine, blood, or breath.

Blood Testing

You can use a blood glucose meter to test for levels of the ketone BHB. Since there are very few factors that alter results found through this method, it’s an accurate way to measure levels. It is more pricy, however, at about $5-$10 for each test strip.

Urine Testing

Use a urine strip. Package instructions might vary slightly, but generally, after around 45-60 seconds you should be able to see the color that indicates the measure of ketones in your urine.

This is the least expensive testing option, but the least reliable. Your body becomes efficient at using ketones when you’ve been in ketosis for a while, so the strips might show a lower level of ketosis than you’re actually in.

Plus, other variables like hydration level and electrolyte levels can change the readings. So it’s better to use this method if you’re brand new to ketosis.

Breath Testing

This method is best used as a supplement to a blood or urine test to help confirm ketone levels. You can use a Ketonix meter to test breath acetone, or BrAce, levels. The advantage of this method is that you can purchase a meter once and used as many times as needed — no strips required.

Is Ketosis Safe? What Are The Long-Term Effects?

A state of ketosis is 100% safe. In fact, low-carbohydrate diets help people to shed unwanted fat, avoid metabolic disease, and perform better at work and at the gym.

When this question comes up, most people are thinking of a few different things:

  1. High-fat diets will kill you
  2. That ketosis is starving the body of important nutrients
  3. Ketosis is actually ketoacidosis, which is much different

Luckily, none of these things are true.

Ketosis Does Not Cause Heart Disease

We’ve all been told that fat, especially saturated fat and dietary cholesterol, cause hardening of the arteries and heart disease. This is simply not true based on the latest research.

Ketosis Won’t Starve You of Micronutrients

If you do keto wrong, you may end up deficient in certain vitamins and minerals. But do keto correctly, eat real, whole foods, and you shouldn’t have a problem.

The fact is: meat, vegetables, and healthy fats are the most nutrient-dense food groups on the planet. High-sugar fruits and grains pale in comparison.

Ketosis vs. Ketoacidosis

People also often confuse ketosis with diabetic ketoacidosis (or DKA). But they are two different things entirely.

DKA occurs when the amount of ketones in the blood is extremely high and can turn the blood acidic. Diabetics can get DKA if they don’t take enough insulin, become dehydrated from not drinking enough fluids, or become hurt or sick. Other causes may be starvation, alcoholism, or an overactive thyroid.

Symptoms of DKA may include:

  • Nausea or vomiting
  • Excessive urination or thirst
  • Hyperglycemia
  • Fruity-smelling breath
  • Gasping or breathlessness

Ketoacidosis is a dangerous state that can be deadly if not treated, and it’s not the same as nutritional ketosis — that we’re talking about here — which is a safe state achieved through a healthy low-carb diet.

Ketosis is a normal metabolic function in which your body is using ketones efficiently and safely. When you adopt a keto diet, you’ll only produce a low level of them in your blood. Enough to give you energy — not nearly enough to harm you.

How Long is it Safe To Be in Ketosis?

Low-carb, high-fat diets are far from dangerous in the short-term. What about over years or decades?

To date, there isn’t much research showing the long-term effects of a ketogenic diet over the course of several years. But there’s no research to suggest that long-term keto is bad for you, either.

Being in ketosis for more than a year shows improvements in:

  • Blood glucose
  • Triglycerides
  • Cholesterol
  • Weight
  • BMI
  • Blood pressure

If your body didn’t like ketones, it’s highly unlikely you’d see so many positive side effects.


Getting started – what is the Ketogenic Diet?

The Ketogenic Diet, also referred to as the Ketosis Diet, or Keto for short, is a way of eating that mimics the effects of fasting. By consuming a diet rich in quality fats, adequate in protein, and low in net carbohydrates (total carbs minus fiber), the body’s metabolism begins to utilize fat as its main source of fuel, rather than carbs. This shift has profound effects on metabolism for both the sick and healthy alike. The diet shows promise for improving or reversing many neurological conditions and metabolic disorders. For the healthy, the diet represents a tool for preventing chronic disease, as well as optimizing cognition and body composition (i.e. fat loss).

What is Ketosis?

The term ketosis refers to a byproduct of the breakdown of fat into useable energy, called ketone bodies, or ketones for short. This fat can be derived directly from a diet (i.e. nutritional ketosis) or from fat stores of the body. Ketosis caused by diet is referred to as “nutritional ketosis”. Ketones are used directly by the body to power itself. This breakdown of fat into useful energy is similar to the process that dietary carbohydrates undergo in producing glucose to fuel the body. In other words, ketones are to fat what glucose is to carbohydrates. Ketosis is defined as having blood ketone levels > .5 millimolar/L.

What are the benefits of Ketosis?

Achieving a state of ketosis can have many benefits from treating chronic illnesses to optimizing performance. While the benefits are well documented, the underlying mechanism of action is not entirely known. The diet seems to enhance the ability of mitochondria, the power plants of our cells, to deliver our bodies’ energy needs in a manner that reduces inflammation and oxidative stress. Through optimizing the way our body uses energy, we fortify our bodies’ ability to combat serveral diseases as well as take on the stressors of our modern way of living.

How do I get into Ketosis?

There are two methods to make the metabolic shift from using glucose to ketones as your main source of energy.

Fasting – the method of complete cessation of caloric intake for a prolonged period of time has been used to treat disease as far back as 400 B.C. when Hippocrates, the Father of Modern Medicine, employed the method for a myriad of ailments. Though this should be done under medical supervision, fasting is a safe, effective (and, some would say, the easiest) way to get into ketosis, quickly. For the average adult, a 48-hour fast will generally result in ketosis. After this fast, adopting a Ketogenic Diet will allow you to stay in ketosis. We recommend starting the fast at least 3 hours before bedtime on the first day, and eating at the same time 2 days later. While fasting means many things to many people, we define it here as the total restriction of macronutrients. We recommend boosting water consumption in order to avoid dehydration, and many find black coffee or plain tea to help maintain focus and performance during the fast. Children go into ketosis much faster and therefore can be started on the diet without fasting.

Diet (nutritional ketosis)– adopting a high fat, moderate protein, and low net-carb diet, will result in ketosis, and will take 2-3 weeks to achieve this state, as defined above. The diet is most basically explained by the ratio of macronutrients (fat, protein and net-carbs) in your diet, as it relates to fat. A classic Ketogenic Diet has a ratio of 4 parts fat, to 1 part protein + carbs (referred to as a 4:1 ratio). This 4:1 ratio is the high end of the spectrum as it relates to fat intake, though modifications to the diet can see this ratio go as low as 2:1. The ratio you adopt depends on the therapeutic benefit you are trying to achieve as well as the diet that is achievable for your lifestyle. There are 5 types of ketogenic therapies, you can learn about them here.

Can a High Fat Diet Be Healthy?

According to David Diamond PhD, “Saturated fat does not clog the arteries: Coronary heart disease is a chronic condition, the risk of which can be effectively reduced from healthy lifestyle interventions. We have known for 150 years that a high carbohydrate diet contributes to fat in the blood and contributes to obesity.”

He goes on to say, “the poor science that was used to support the idea that increased fat intake increases cholesterol and damages arteries was authored by Ancel Keys who had no background in nutrition, but did have a BA in Economics and a PhD in Fish Physiology. Keys’ theory that fat in diet causes increased risk for high cholesterol and heart attack was based on extremely flawed science and “became dogma without ever being rigorously assessed.”

“A generation of citizens has grown up since the Diet/Heart Hypothesis (of Ancel Keys) was launched as official dogma. They have been led by the greatest scientific deception of our times: the notion that consumption of animal (saturated) fat causes heart disease.”
George Mann MD, Nutrition Today, 1985.

“The belief that atherosclerosis is due to high cholesterol has been perpetuated by powerful forces using tactics to preserve the profits and reputations of those who promote them.” Paul Rosch M.D, Scandinavian Cardiovascular Journal, 2008.

“The diet heart hypothesis is sustained by social, political and financial institutions which have little to do with science and established success in public health.” Uffe Ravnskov MD PhD, 2008.

How long should I be on the Ketogenic Diet?

We at the Charlie Foundation believe that a 3-month commitment to the diet is the minimum trial period necessary to understand if Ketogenic Therapy is right for the individual. Since most people following a western diet are not proficient at metabolizing fat optimally, this period allows the body time to become “fat-adapted”, utilizing dietary fat efficiently and effectively. There are a variety of nutritional plans that will enable a ketogenic lifestyle, and flexibility is one of the hallmarks of the diet that make it easy to adopt as a life-long tool to enhance your health. Our nutritionists can help figure out both the short and long-term options best suited for you and your lifestyle.

Types of Ketogenic Diets:

There are a variety of diets that will allow you to get into ketosis. The major differentiating factor between them all is the number of calories that come from protein, carbs and fat, which are what we call “macronutrients”, or nutrients in our food that have a caloric value. The three macronutrients differ in many ways, namely, their caloric values, as well as how the body uses them. Fat is the most calorically dense macronutrient, having 9 calories per gram, compared to 4 calories per gram for both carbs and protein. In a homeostatic state, the body utilizes fat and carbs for energy production, while it uses protein to rebuild the cells of the body. While this is generally the case, an overconsumption of protein can lead the body to break down the excess protein into glucose, resulting in the same end product as carbs.

  • Classic Ketogenic Diet
  • Modified Ketogenic Diet
  • MCT Oil Diet
  • Modified Atkins
  • Low Glycemic Index Diet (LGIT)
  • Intermittent Fasting

Am I a candidate for the Ketogenic Diet?

While the short answer is yes for the majority of people consuming a western diet, we urge you to consult your general practitioner prior to making the switch to Keto. The Charlie Foundation will provide you with the information and tools necessary to adopt the diet, and partnering with your doctor during this process will ensure the most therapeutic outcome. To better understand if you are a candidate for the Ketogenic Diet, we have listed disease states below that studies are showing promising results for treating directly, or having compounding effects when combined with other medical treatments. If you have arrived at the Ketogenic Diet as a tool to tighten the screws of your overall health, fitness, and cognition, we recommend you jump directly to the different types of Ketogenic Diets that exist.

Keto has the power to heal.

Hundreds of studies have been performed showing therapeutic benefits of the Ketogenic Diet for a variety of disease states. Originally studied for its effects on epilepsy, the diet is now showing promise for a multitude of illnesses that have an underlying metabolic dysregulation, including but not limited to:

  • Epilepsy
  • Brain Tumor/Cancer
  • Alzheimer’s Disease
  • Parkinson’s Disease
  • Tramatic Brain Injury
  • Mitochondrial Disease
  • Autism
  • ALS
  • Brain Health
  • Diabetes: Type-I and Type II

If you or a loved one have been diagnosed with any of the above illnesses, are genetically predisposed to developing any of them, or feel your lifestyle and/or environmental factors may increase your chances of developing any of them, the Ketogenic Diet may be a great tool to improve your health outcome.

Getting Started

If you think you can benefit from adopting a Ketogenic Diet, we encourage you to consult one of our nutritionists so that we may guide you towards the most fruitful option given your specific needs.

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