Ketogenic diet and heart health


Keto Diets and Heart Health: What’s the Risk?

Keeping track on keto

People on the typical keto diet plan should consume about 75 percent of their calories from fat. Proteins comprise 20 percent — and carbohydrates make up just 5 percent.

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Cutting out low-quality carbs found in soft drinks and white bread, for instance, is a good idea for anyone, Ryskamp says. Sugar and starches raise the risk for obesity, diabetes and heart disease.

Even with those omissions, vigilance is still needed.

The keto diet isn’t a green light to load up on butter and bacon, which can trigger the health issues you’re trying to remedy or avoid.

“Make sure that the fats you are eating are healthy fats and not processed ones,” says Ryskamp, who notes good sources include extra virgin olive oil, avocado, salmon (for omega-3 fatty acids), nuts and nut butters. “From a cardiovascular standpoint, these are all better.”

SEE ALSO: Can an Elimination Diet Help You Lose Weight?

Healthful, too, is a steady intake of green vegetables such as broccoli, celery, kale and spinach — all of which are permitted on the keto diet.

Those foods matter: A 2010 study of low-carb dieters found that those who focused on vegetable-based sources of fat and protein had a 23 percent lower risk of heart disease than those who relied more heavily on meat.

Weight gain after keto

Still, the long-term viability of keto isn’t clear.

While the short-term results are well-documented, there’s little research on whether following a keto diet is a safe or effective way to keep weight off indefinitely.

SEE ALSO: Fish, Fruits, Healthy Fats: What Heart Patients Should Eat

“Based on the literature, keto diets may be associated with some improvements in cardiovascular risk factors such as obesity, and type 2 diabetes, but these effects are usually limited in time,” Ryskamp says.

Worse, she adds, many people gain back the pounds after stopping keto.

Research has found that weight, cholesterol and blood pressure fluctuations caused by yo-yo dieting can increase the risk of heart attack or stroke by 40 percent.

Says Ryskamp: “The best diet for an individual is one they can achieve the positive results they desire, such as steady, maintainable weight loss and improvement in biomarkers.”

Consult your doctor before starting a keto diet

Regardless of their health status, all patients should consult their doctor before going on the keto diet.

The reason: to rule out any existing concerns or ailments that could make the approach harmful to their heart or the rest of their body.

A small subset of people appears to experience increased cholesterol levels on a low-carb diet, so a family history of heart disease should be discussed.

SEE ALSO: Millions More People Now Have High Blood Pressure. Why That’s a Good Thing

“It is important to rule out a genetic condition like familial hypercholesterolemia, which is characterized by very high cholesterol levels and a high risk of heart disease,” Ryskamp says.

Because excess protein must be broken down by the kidneys, people with kidney problems should avoid keto. Those with liver problems also face specific risk, as the diet involves higher concentrations of fat for the body to process.

Beyond that, dietary basics should be part of the conversation — as a keto regimen can present unique nutritional deficiencies for herbivores and omnivores alike.

“If you’re doing a very low-plant-based diet, you run the risk of not having adequate intake of some of your phytonutrients and micronutrients,” Ryskamp says. “And it would be difficult for a vegetarian to adopt a ketogenic diet without taking some sort of supplement.”

It’s also a good idea to ask about checking in with your doctor more frequently.

“As long as a patient is doing it well and we’re doing more good than harm, they should see positive results,” Ryskamp says.

Why Paleo and Keto Diets May Be Unhealthy for Your Heart

Whole grains aren’t the only source of fiber. Fruits and vegetables also contain fiber, and not every one of them is marked off the lists of acceptable foods in keto and paleo plans.

But it’s the type of fiber that’s in the whole grains that concerns Rachel Fine, MS, RD, CSSD, CDN, owner of To The Pointe Nutrition, a nutrition counseling firm in New York City.

“The fact that paleo restricts whole grains is the biggest concern regarding inadequate fiber intake. Whole grains are particularly high in insoluble fiber, which, unlike soluble fiber — that coming primarily from veggies and fruit — helps to add bulk to stool. This plays a major role improving digestive regularity,” Fine said.

Some approaches to both keto and paleo diets emphasize leaner, healthier forms of protein and not red meat, which the researchers in this study point out was a major component of the study participants’ diet.

“This is why I developed Ketotarian, my plant-based ketogenic eating plan,” said Will Cole, IFMCP, DC, and author of “The Inflammation Spectrum.” “It focuses on healthy plant-based sources of fat instead of meat and dairy but allows for heart-healthy, wild-caught fish for pescatarians.”

“This way of eating also encourages more vegetable intake, as it is plant-based to get in essential fiber for a healthy gut,” he added.

“Since some people do have sensitivities to legumes and grains, Ketotarian ensures you are still able to get in enough fiber through higher intake of vegetables, such as artichokes, broccoli, and Brussels sprouts,” Cole said.

Jedha Dening, a nutritionist, diabetes educator, and founder of Diabetes Meal Plans, says people following a keto or paleo diet should emphasize the fiber sources that are permitted.

“A person does not need to eat whole grains to obtain adequate fiber. This is a common misconception,” Dening said.

“For instance, 1 cup brown rice contains about 3.5 grams of fiber; 1/2 avocado contains around 7 grams; and 1 cup of broccoli contains 2.4 grams. You can still obtain plenty of fiber when following a paleo or keto diet by including nonstarchy vegetables, nuts and seeds, and even lower-carb fruits.”

“The key is, people need to include higher-fiber foods in their diet and not just eat meat and cheese all day,” Dening continued. “Balance in the context of these diets is certainly the key.”

Fine, on the other hand, says these diets place too many restrictions on foods that research shows again and again are healthy.

“Restrictions of any kind are never advisable,” Fine said. “Diets that are highly restrictive, such as paleo, risk negative consequences. Restrictions result in a host of biological consequences that cause us to literally want what we think we ‘can’t have.’”

“When we restrict carbs and/or fat, the body releases specific hormones to counter the restriction, promoting increased cravings of said macronutrients,” Fine said.

“This is because our body relies on both carbs and fat for very specific metabolic functions,” she explained. “When one or both of these macros is not available from dietary restriction, the body will fight until you can no longer resist.”

Rather than extreme restrictions, Fine advises an “inclusive approach,” which she says is “key to long-term success” of any diet.

“Instead of rules, make choices. Add more minimally processed, nutrient-dense, plant-based foods, like fresh produce, nuts, seeds, and legumes to your meals. Psychologically, an inclusive approach allows for enjoyment of all foods,” Fine said.

Is the Keto Diet Bad for Your Heart?

Keto has been in the public consciousness for a while now, with scores of vocal fans, but as we ease into a new decade, keto backlash seems to be picking up steam. So is keto bad for your heart, and your health in general?

The low-carbohydrate ketogenic diet can certainly sound too good to be true. (Eat butter! And red meat! And cheese! Eschew carbs and lose weight!) But search #ketotransformation on Instagram and you’ll see well over 1 million posts (seemingly) proving weight loss is a result of slipping into ketosis. Or just look at Vinny from “Jersey Shore.” Or Al Roker.

Related Reading: The Best Low- and No-Sugar Cookbooks for Keto, Paleo, and Diabetic Diets

So what are the downsides of the keto diet (besides giving up bread, meticulously tracking net carbs, and the keto flu)?

Keto’s Impact on Your Health

Let’s get back to the butter and red meat and not eating carbohydrates, which would have anyone with a baseline knowledge of cardiovascular disease and heart attack asking, Is the keto diet bad for your heart? It seems like a low-carb, high-fat diet would be bad news for your ticker (and your cholesterol levels), but that may not be the case.

In fact, one 2017 review of studies published in the journal “Nutrition” found that a keto diet could improve HDL cholesterol levels, as well as reverse the course of Type 2 Diabetes by controlling blood glucose levels. In addition, the ketogenic diet has been proven as an effective dietary treatment plan for some patients with epilepsy, and some studies suggest it could help treat symptoms of Alzheimer’s disease and Parkinson’s disease. That said, most experts agree that more research is needed, and that the improvements in cardio risk factors may be limited.

Certain research also suggests that the ketogenic diet may have some adverse side effects, including potential kidney and heart complications (think kidney stones, especially if someone on keto isn’t hydrating properly). In addition, there have not been enough studies conducted over more than 2 years to determine the long-term effects of the ketogenic diet, which means we can’t be certain how producing more ketones may affect the body or the heart over a period of multiple years.

Other side effects include digestion issues like constipation, low blood sugar, exhaustion, and headaches, although most side effects (also called the keto flu) should subside after the first few days on the diet as your body slips into ketosis.

Keto Commitment vs Casual Keto

Like other low-carbohydrate diets, while the ketogenic diet has some proven benefits, most experts say these benefits are greatly diminished if you “sort of” follow the ketogenic diet. For instance, you want to be keto compliant, so you order eggs and bacon to make sure you’re hitting your macros for protein and fat intake…but the French toast looks delicious, so you grab some from your dining mate’s plate. At this point, your body is no longer in ketosis, and the fatty foods on your plate might be doing more harm than good, says Doctor Stephen Sinatra, a cardiologist in New York City.

While some studies show that a ketogenic diet may actually lower cholesterol levels for people who follow a strict ketogenic diet, experts worry that “keto” has become code to some for “go nuts at the Brazilian barbeque” says Sinatra, without fully committing to keto guidelines, including making sure the low-carb diet is done under the supervision of a doctor.


So can the ketogenic diet and remaining in a state of ketosis be a healthy way to help you achieve your weight loss goals without inciting heart disease? It depends on how strict you plan to be while following the diet, and to make smart choices in the foods you are allowed to have on the plan. Yes, you can technically have a fully keto meal from the drive-thru. But that red meat double double will most likely be loaded with saturated fat.

“It’s important not to go overboard on saturated fats and focus on healthy, monounsaturated fats,” notes Sinatra. That’s because saturated fats are more likely to raise your LDL cholesterol level, regardless of whether or not you’re following the keto diet. Some smart keto choices and healthy fats include eating lean meats, fish, leafy green veggies like spinach and kale, above ground, non-starchy vegetables like cauliflower, broccoli and eggplant, and healthy oils like coconut oil, grape oil, and flaxseed oil.

Related Reading: How to Make Keto Meal Prep a Success | The Best Keto Snacks We’ve Tried

If a plant-based diet doesn’t sound sustainable to you, the Mediterranean diet (which allows lean meats and lots of fish and seafood) could be a good middle ground. The important part is picking something that you can work with though the long haul, as any kind of yo-yo dieting is uhealthy (and likely to backfire when it comes to long-term weight loss).

Bottom Line

Bottom line, when it comes to the ketogenic diet and heart health research echoes what Instagram before and afters show: The ketogenic diet can be an effective form of weight loss. But it may not be the best option for you to lose weight. Talking to your doctor and getting a full workup, including blood work, prior to starting a ketogenic diet can help you monitor how the diet is affecting your body, including your heart. And the same is true before you embark on any weight-loss plan.

Header image courtesy of The Picture Pantry / Alloy / Getty Images

Ketogenic diet: What are the risks?

Fad diets often come with big promises of weight loss and optimum health, but at what risks? University of Chicago Medicine Ingalls Memorial dietitians say the ketogenic or keto diet, which has gained popularity in the last several years, is extremely strict and difficult to maintain.

Rachel Kleinman, RDN, LDN, clinical dietitian at Ingalls, said the keto diet is primarily used to manage seizures in children with epilepsy. Research on the diet’s effectiveness in treating obesity or diabetes is limited.

Ketosis is a metabolic adaptation to allow the body to survive in a period of famine. Your body will break down ketone bodies, a type of fuel the liver produces from fat, instead of sugar or glucose from carbohydrates.

To achieve ketosis, the diet requires you eat 75 percent of your calories from fat, compared to 20-35 percent normally. It also requires 5 percent of calories from carbohydrates, about 20-50 grams per day, and 15 percent of calories from protein. Kleinman said it takes about 72 hours for ketosis to kick in. “It’s really an all or nothing diet,” Kleinman said.

People following the keto diet should be eating foods like fatty fish, eggs, dairy, meat, butter, oils, nuts, seeds and low-carb vegetables. “Fat bombs” like unsweetened chocolate or coconut oil can help people reach their daily goals for fat intake. Keto-compliant foods like red meats and nuts can be costly, Kleinman said. Keto-branded products like keto coffee and other supplemental products are also both costly and unnecessary.

Wellness Dietitian Mary Condon, RN, LDN, said the keto diet may result in weight loss and lower blood sugars, but it’s a quick fix. “More often than not, it’s not sustainable. Oftentimes weight gain may come back, and you’ll gain more than what you lost,” Condon said.

Condon said you should always consult your primary care doctor before starting any new diet.

“If you are on diabetic medication that causes low blood sugar, those meds may need to be adjusted within a few days,” Condon said. “There are heart-healthy sources of fat, however if that person is not educated on heart-healthy sources of fat, they may consume excessive amounts of saturated fats that can increase your risk of heart disease,” Condon said.

The keto diet could cause low blood pressure, kidney stones, constipation, nutrient deficiencies and an increased risk of heart disease. Strict diets like keto could also cause social isolation or disordered eating. Keto is not safe for those with any conditions involving their pancreas, liver, thyroid or gallbladder.

Kleinman said someone new to the keto diet can also experience what’s called the “keto flu” with symptoms like upset stomach, dizziness, decreased energy, and mood swings caused by your body adapting to ketosis.

Both Condon and Kleinman said they wouldn’t recommend the keto diet to their patients because it is ultimately not realistic or sustainable. The diet restricts fresh fruits and vegetables, whole grains and low fat dairy that can help with long term weight loss and overall health.

“There’s not one diet that’s good for everyone,” Kleinman said. “Do your research, consult a dietitian, discuss with your doctor, and make sure you’re being safe.”

Call the Health and Nutrition Experts at UChicago Medicine Ingalls Memorial at 708-915-8850 to discuss nutrition counseling programs offered to meet your personalized needs.

By Stephen T. Sinatra, M.D., F.A.C.C., F.A.C.N., C.N.S., C.B.T.

If you haven’t heard about the ketogenic diet, you probably just got back from vacationing on Mars…

In all seriousness, though, “keto” dieting has taken the world by storm. Celebrities and fitness experts swear by its weight loss powers, athletes say it boosts their performance, and patients with Alzheimer’s, epilepsy, and other serious diseases have been able to use the ketogenic diet to treat, halt progression, or even reverse their conditions.

Even crazier, all of these claims about the ketogenic diet may actually be valid.

What Is the Keto Diet?

While it may seem like the latest weight loss fad, the ketogenic diet actually has a 100-year-long history.

In the 1920s, physicians used a ketogenic diet to treat epilepsy in children. Back then, researchers knew that extreme hunger (or even starvation) decreased the incidence of seizures. But instead of forcing kids to go hungry in an effort to treat their epilepsy, they created a diet to mimic the process that was reducing the seizures in the first place: ketosis.

During ketosis, the body uses fat for energy. It doesn’t normally, though. The body’s preferred fuel source is glucose, which is the easiest molecule for it to convert into energy. This glucose comes from dietary carbohydrates.

It’s an efficient system, especially for those who eat well-balanced diets with healthy ratios of fats, carbs, and proteins. But let’s get real for a second… Many (dare I say, most) people in this country follow the “standard American diet,” which as far too rich in refined carbs and sugars. Such high-carb diets lead to the overproduction of glucose. There are a few things that happen when too much glucose is coursing through the blood. The body uses whatever glucose it needs for energy. The remaining glucose then gets stored in the liver as glycogen. If there’s any that’s left after that, the body converts it and stores it as fat. (And you know what comes next: weight gain, then diabetes, heart disease, and other conditions related to obesity.)

With the ketogenic diet, you dramatically lower your intake of carbs and increase your intake of fats. As a result of this carb-limiting diet, the body no longer has the glucose it needs for energy. So it seeks out an alternative energy source—and that source is fat.

Fat starts to get broken down into ketone bodies (ketones for short), which generate energy and continue to do so until carbohydrates are reintroduced and glucose can once again be used. If that doesn’t happen, it will keep burning fat reserves indefinitely.

Benefits of the Ketogenic Diet

Research clearly shows that the ketogenic diet can be effective for weight loss and, as mentioned earlier, treatment of some types of seizures. But that’s not all. It shows promise with other neurological diseases like Alzheimer’s, as well as diabetes.

Weight loss is perhaps the main reason people want to give the ketogenic diet a try. And for many, it really works. The process of ketosis melts fat away as the body converts it to ketones, and noticeable results can often be seen within a week. The process of ketosis also happens to decrease appetite, which accelerates weight loss even more.

One study followed 83 obese patients who took part in a 24-week ketogenic diet. Not only did they lose weight, their LDL cholesterol and triglycerides significantly decreased, and their beneficial HDL cholesterol went up.

In a more recent study of 19,036 obese patients on a ketogenic diet, 15,444 experienced impressive weight loss (“a rapid 10% weight loss, 57% of which was fat mass”), with no major adverse effects. The researchers wrote that the diet is “safe, fast, inexpensive, and has good one-year results for weight maintenance.”

People who are overweight and have diabetes may also benefit from going keto. In a 24-week trial of 363 obese participants (102 of whom had type 2 diabetes), researchers wanted to see how a ketogenic diet compared to a low-calorie diet when it came to several measures, including weight, body mass index, waist circumference, blood glucose levels, hemoglobin, cholesterol, and triglycerides.

While both diets improved markers, the keto group saw far greater changes. The researchers concluded, “This study shows the beneficial effects of a ketogenic diet over the conventional low-calorie diet in obese diabetic subjects. The ketogenic diet appears to improve glycemic control…”

The keto diet also shows potential for slowing the progression of Alzheimer’s. For one, ketones appear to be neuroprotective, helping to prevent cognitive decline and degeneration in an aging brain. Among other benefits, ketosis can boost the activity of the antioxidant glutathione peroxidase in the hippocampus.

In an animal study, ketosis prevented amyloid beta plaques—a hallmark sign of Alzheimer’s. And in a trial of 152 people with mild to moderate Alzheimer’s, those who took an oral compound that induced ketosis showed substantial improvements on cognition tests by day 45, compared to the placebo group.

This research is still preliminary, but considering all the Alzheimer’s treatments available right now do little to stop disease progression, ketosis may provide the hope that these patients need.

Keto Diet Foods

A classic ketogenic diet involves completely eliminating all sugars (honey, maple syrup, agave, white/brown sugar, molasses, coconut sugar, etc.), all starchy veggies (tubers like white and sweet potatoes, and root vegetables such as beets, carrots, etc.), all grains and legumes, and most fruit. (It should also go without saying that all prepared and processed foods are no-nos.)

What’s left? Lots of fat, moderate protein, and a stingy amount of low-glycemic carbs. That translates to about 75% of calories from fats, 20% from proteins, and the remaining 5% or less from carbs. (Depending on body weight, this typically amounts to about 20–60 grams of carbs per day.)

Here’s a rundown of the allowable keto diet foods:

Drawbacks of the Ketogenic Diet

While I’m sure you’ll find many nutritionists and experts warning about dangers of the keto diet, I don’t really think there’s anything too harmful about it—as long as the fats you eat are primarily the healthy monounsaturated variety and you don’t go overboard on saturated fats. I would also make sure to eat only grass fed meat and dairy products, and free range or organic poultry and eggs to avoid GMOs and pesticides.

There are a few of the side effects to be aware of, though:

  • Frequent urination: The first few days of starting the ketogenic diet, as your body burns through all your stored glucose, you release a lot of water and excess sodium.
  • Hypoglycemia: Low blood sugar is common the first few days as well, especially for people who are used to eating a lot of carbohydrates. Dizziness, tiredness, shakiness, and hunger are symptoms of hypoglycemia, but they eventually subside once the body adjusts.
  • “Ketosis flu”: Many people experience flu-like symptoms the first three or four days of starting the keto diet. This also subsides.
  • Digestive issues: Constipation or diarrhea can occur due to the drastic change in macronutrient ratios. To make sure you’re getting enough fiber, eat lots of “allowable” vegetables and consider adding a fiber supplement like psyllium husk powder.
  • Bad breath: Acetone is one of the ketones created during ketosis. It definitely has a distinct odor that many find unpleasant, but it’s a good sign your body is in full-on fat-burning mode. Most keto dieters report their bad breath going away after a few weeks.

If there’s any concern I have about going keto, it’s this…

One of the most important characteristics of any diet or eating plan is not its ability to help you lose weight…because in reality, any diet promotes weight loss, especially in the short term. It’s the sustainability of the diet…meaning, is it a plan that you can easily follow for the rest of your life, and enjoy and thrive on? Does it provide all the nutrients you need to stay healthy? Does it help you not only maintain a decent weight, but also excellent heart health? While some research has shown that the keto diet is safe and sustainable, I’m not totally convinced.

Altering your macronutrient ratio so drastically is really hard to do…and it’s even more difficult to keep it up for months at a time. Can you imagine never ever having a strand of spaghetti, a banana, or a glass of wine again? If you’re a follower of strict keto diet, that’s your life.

This is why I’m such a proponent of the Pan-Asian Modified Mediterranean Diet (PAMM), which is a blend of the best of traditional Asian and Mediterranean dietary approaches.

The PAMM diet consists of a healthy, balanced ratio of fats, low-glycemic carbohydrates, and lean proteins—and it even allows for a glass of wine or occasional bowl of pasta, if desired. You never feel deprived, and for that reason alone, PAMM is extremely easy to follow indefinitely.

With that said, though, I don’t see any major reason to not give the ketogenic diet a try for a few weeks or months if you’re really struggling with your weight. (If you want to try it to help resolve or treat a serious health issue like epilepsy or Alzheimer’s, I highly recommend not going it alone and instead working with a doctor who’s knowledgeable in this area.)

My colleague and friend, Dr. Dan Pompa, is a strong believer in a “diet variation” strategy, where you adopt a keto diet for a few months, then add more starchy veggies and fruits back into the program (while continuing to avoid grains and refined sugars), then returning to keto. In his experience, the diet variations trigger metabolic shifts which result in weight loss.

And, if the very strict classic keto diet is too much for you, even a modified version—40% of calories from fat and 30% from both carbs and protein—has been shown to aid in weight loss. (Even better, a modified keto diet is a much more sustainable diet to follow long term.)

Finally, if you’re reading this and thinking, “Nope, Dr. Sinatra, the ketogenic diet is definitely not for me,” but you’re still curious about the potential benefits of ketosis, try intermittent fasting. As I mentioned earlier, “starving” for short periods of time puts the body into ketosis. With intermittent fasting, you’re not restricting any food groups; you’re simply eating in a short 8-hour window during the day (typically between noon and 8pm), and avoiding food the rest of the time. Lots of research praises intermittent fasting for weight loss and blood sugar control.

Whatever you choose to do, don’t lose sight of the big picture: Your health. If you look and feel absolutely fantastic on any particular diet, then it’s probably the right one for you. But if you look and/or feel sluggish, sick, and just plain terrible, then your body is telling you loud and clear that you aren’t giving it something it needs. It’s then time to reevaluate and try something new.

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  • Dashti HM, et al. Long-term effects of a ketogenic diet in obese patients. Exp Clin Cardiol. 2004 Fall;9(3):200-205. Last accessed June 20, 2018.
  • Gianfranco C, et al. Ketogenic enteral nutrition as a treatment for obesity: short term and long term results from 19,000 patients. Nutr Metab (Lond). 2012;9:96. Last accessed June 21, 2018.
  • Hussain TA, et al. Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes. Nutrition. 2012 Oct,28(10):1016-21. Last accessed June 20, 2018.
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  • Henderson ST, et al. Study of the ketogenic agent AC-1202 in mild to moderate Alzheimer’s disease: a randomized, double-blind, placebo controlled, multicenter trial. Nutr Metab (Lond). 2009 Aug 10;6:31. Last accessed June 20, 2018.

Diet and Heart Disease—What Every Cardiologist Should Know

Throughout my training as a cardiologist, from medical school through fellowship, it became increasingly clear that the single major cause of poor health in my patients was poor diet. Yet, like my fellow medical students, house staff, and attendings, I had received very little relevant training in nutrition, lifestyle, or effective behavior change strategies. I could perform and interpret a dizzying array of technologically-based diagnostic tests and interventions, but I had not been given the tools to address the root causes of my patients’ illnesses and distress. Remarkably, I faced my patients every day with only a subset of the full complement of necessary information and approaches to improve their health.

Today, many friends, colleagues, and patients in the health care system express these same frustrations. Suboptimal diet remains the leading cause of poor health in the US and globally,1,2 with most of this due to cardiovascular and metabolic diseases. At the same time, tremendous advances in nutritional, behavioral, and policy science provide a clear roadmap for evidence-based dietary priorities,3 clinical behavior-change strategies,4,5 and health systems, community, and national approaches to improve cardiometabolic health.5-7 The disconnect between what we know versus what is being done in nutrition is larger than for anything else in health care. Although this presents a remarkable irony, it also presents a remarkable opportunity to reduce disease and rein in spiraling health care costs.

Cardiologists should be leading this charge. Cardiac disease, stroke, and their related metabolic disorders and risk factors represent eminently preventable conditions that together consume a substantial proportion of national health resources. We are at the front lines of this battle, and we must maximally utilize every defense in our arsenal to make a difference in our patients’ lives. Recognizing this, the American Heart Association formally prioritized lifestyle and behavior change in its 2020 Strategic Impact Goals: the mission is no longer just about treating or even preventing disease, but achieving health.8 I was fortunate to participate in the writing of these goals, particularly by contributing to the dietary targets, which appropriately focus on food-based priorities such as increasing fruits, vegetables, seafood, and whole grains, and reducing sugar-sweetened beverages and a pernicious additive, sodium. In the summer of 2015, the American College of Cardiology (ACC) held its first-ever Population Health Retreat, aiming to shift the ACC’s paradigm away from disease recognition and management and toward prevention: healthier lifestyles, improved nutrition, and greater physical activity.9 ACC President Kim Allan Williams, Sr., MD, FACC, highlighted this new focus and declared, “We have to become life coaches and good examples of healthy lifestyle in order to promote lifestyle improvement.”9

To enable this transformation toward successfully addressing diet and behavior, what should every cardiologist know? First, the historical prioritization on reducing total fat, saturated fat, and dietary cholesterol is outdated and incomplete.10,11 Evidence from a broad range of research paradigms demonstrates that the focus should be on healthful food-based diet patterns, including increased intakes of beneficial foods such as fruits, nuts, vegetables, minimally processed whole grains, legumes, polyunsaturated and phenolic-rich vegetable oils, seafood, yogurt; and reduced intakes of sugar-sweetened beverages, processed (preserved) meats, and foods rich in refined grains, starches, and sugars (Table 1).3 Red meats should be consumed moderately to prevent weight gain and diabetes, and butter used occasionally but not emphasized.12 Two industrial additives – sodium and partially hydrogenated vegetable oils – should also be avoided. Such a diet meaningfully lowers total carbohydrate, due to less refined carbohydrates, and increases total fat – optimally exceeding the previously recommended cap of 35% of calories – due to increased nuts, fish, and vegetable oils.11 However, these macronutrient changes reflect a secondary consequence, not primary aims, of the food-based priorities. By understanding this set of priorities, cardiologists and other allied health professionals can appropriately guide teaching and behavior change efforts.

Table 1: Evidence-Based Dietary Priorities for Cardiovascular and Metabolic Health



Consume More


3 servings per day

Whole fruits (fresh, frozen, canned) are preferable to 100% juice; limit the latter to about 1 glass per day.

Nuts, seeds

4 servings per week

Choose from a variety of different nuts and seeds.

Vegetables, including legumes (excluding white potatoes)

3 servings per day

Minimize starchy vegetables, especially white potatoes.

Minimally processed whole grains

3 servings per day, in place of refined grains

As a practical rule of thumb, choose grain products with at least 1 g of fiber for every 10 g of total carbohydrate (i.e., a carb:fiber ratio of <10:1).27

Fish, shellfish

2 or more servings per week

Aim for oily fish, e.g. salmon, tuna, mackerel, trout, herring, sardines.

Dairy products, especially yogurt and cheese

2-3 servings per day

The choice of whole-fat vs. low-fat can be based on personal preference, as current evidence is insufficient to confirm which is superior.

Vegetable oils

2 to 6 servings per day

Aim for polyunsaturated and/or phenolic-rich oils and soft spreads, such as from soybean oil, canola oil, and extra-virgin olive oil.

Consume Less

Refined grains, starches, sugars

No more than 1-2 servings per day

Do not focus on total or added sugars alone, as low-fiber, high glycemic complex carbs (refined grains, starches) appear similarly harmful.

Processed meats

Don’t eat

Avoid meats preserved with sodium or nitrates, e.g. hot dogs, bacon, sausage, pepperoni, salami, and chicken, turkey, ham, or beef deli meats.

Red meats

No more than 2-3 servings per week

Fresh or frozen beef, pork, lamb.

Industrial trans fat

Don’t eat

Avoid foods made with partially hydrogenated vegetable oils.

Sugar-sweetened beverages

Don’t drink

Avoid sugar-sweetened soda, sports drinks, energy drinks, iced teas, and fruit drinks.


Up to 1 drink per day for women, 2 drinks per day for men

For those who drink alcohol, moderate daily use appears optimal, without clear differences in health effects between wine, beer, or spirits.


No more than 2,000 mg/d

Avoid packaged, restaurant, or deli foods high in sodium. Major sources include bread, chicken, cheese, processed meats, soups, and canned foods.

*Based on a 2,000 kcal/day diet. Servings should be adjusted accordingly for higher or lower energy consumption.
Modified from Mozaffarian D. Dietary and policy priorities for cardiovascular disease, diabetes, and obesity: a comprehensive review. Circulation 2016 Jan 8.

Second, cardiologists should be champions of the distinction between diet quality versus quantity. “Poor diet” and “obesity” are neither synonymous nor interchangeable concepts. Healthful diet patterns operate through numerous mechanistic pathways and risk factors, with obesity representing only a small subset of these pathways.3 Regardless of body weight, healthful diet patterns substantially reduce cardiovascular risk, while also stabilizing long-term weight gain.3,10,13,14 Thus, diet quality, rather than weight and adiposity, should be the primary focus of dietary counselling. Indeed, focus on calorie-counting can lead to paradoxical and potentially harmful recommendations, whereby metabolically harmful, obesogenic “low-calorie” foods are prioritized over minimally processed “high-calorie” foods that improve both metabolism and long-term weight homeostasis.15 Every calorie in a food is thermodynamically equivalent in a test tube. Yet, different foods produce complex and divergent effects on the physiologic compensatory mechanisms for long-term energy balance: satiety, glucose-insulin responses, hepatic fat synthesis, adipocyte function, brain craving, the microbiome, and even metabolic expenditure.13,16,17 For long-term weight homeostasis, foods rich in rapidly digestible, low-fiber carbohydrates appear particularly adverse, while fruits, nonstarchy vegetables, nuts, yogurt, fish, and whole grains appear protective.13,16,17 Of course, for short-term weight loss, calories are king: this explains why nearly any diet can be effective in the short-term. Many overweight and obese patients effectively lose weight on very low-carbohydrate diets, a reasonable first choice for intensive short-term weight loss, especially among patients with insulin resistance.18,19 Once weight loss has been achieved, patients should shift back toward healthful, food-based diet patterns (Table 1).

Third, cardiologists must be familiar with effective behavior change strategies and vigorously advocate for health care system improvements to facilitate these efforts. Successful behavior change methods incorporate shared goal setting, self-monitoring, feedback, scheduled follow-up, and peer support.4 These provider efforts must be potentiated by changes to health systems, including regular clinician training, coordinated care by multi-disciplinary teams, electronic health records that assess and monitor diet, electronic systems for patient feedback and regular follow-up visits, and restructuring of reimbursement guidelines, practice goals, and quality benchmarks to include nutrition.5 The Affordable Care Act’s provisions on accountable care organizations, whereby medical groups, physician-hospital organizations, and integrated delivery systems will share medical and financial responsibility for the health of populations, provides a further incentive to align priorities toward nutrition and behavior change.20,21 Novel internet, mobile, and personal technologies may also be effective and complement clinical efforts, but require additional investigation to confirm sustained benefits beyond 6-12 months.

Fourth, cardiologists and our professional societies should be actively leading our communities and our nations toward evidence-based policies and quality standards that protect the public and shift the population toward health, just as we have done for automobile safety, drug safety, air and water quality, worksite safety, building construction standards, food-borne pathogens, and tobacco smoking. A handful of sensible dietary policies and quality standards would produce major health benefits across the population while also reducing inequities in nutrition and health (Table 2).6,7,22,23 Such “soft healing” efforts are crucial complements to the current “hard healing” focus of modern health care and also help to address disparities in knowledge, cost, and access.24

Table 2: Evidence-Based Policy Priorities for Better Population Nutrition

  • State or national tax and subsidy framework to reflect the real costs of food.22
  • Strong, health-aligned quality standards and incentives in all food assistance programs, such as the Supplemental Nutrition Assistance Program (SNAP, formerly Food Stamps).
  • Food industry, retailer, and restaurant incentives (and disincentives) to develop and market healthier foods.
  • Comprehensive school and workplace wellness programs including nutrition education, environmental change, family and peer support, and supportive organizational policies.
  • Quality standards on contents of salt and industrial trans fat; quality standards on foods marketed to children.
  • Health system reimbursement guidelines, practice goals, and quality benchmarks that prioritize nutrition and behavior change.
  • Long-term agricultural policies that encourage the production, storage, transport, and sales of healthier foods.

Finally, cardiologists must be familiar with major fads and misconceptions in popular nutrition, providing a stout line of defense against the onslaught of variably accurate newspaper and magazine articles, books, television personalities, social media, blogs, and websites. Recognizing the crucial role of nutrition in their health, patients and their families increasingly arrive at their providers’ offices with a virtual panoply of confused dietary impressions. These can frustrate and bewilder the practicing clinician, already faced with brief visit durations, increasing administrative paperwork, and complex and growing drug, device, and procedural options. Examples of popular topics in nutrition today include gluten-free, organic, genetic modification, local, grass-fed, paleo, low-carb, and vegan. Because of the dynamic trends in these areas and the naturally evolving science over time, the practicing clinician should regularly refer to updated, reliable sources of scientific information, such as found on academic websites or university nutrition newsletters.25,26 In general, these popular concepts often have a minor or uncertain influence on health, compared with the “big picture” of overall foods and diet patterns consumed. Among current fashionable concepts, a high-fat, Mediterranean dietary pattern is perhaps closest to evidence-based nutritional priorities (Table 1), and thus may be a useful construct for many patients.

In sum, modern evidence provides strong impetus toward healthful, food-based dietary patterns for improving cardiometabolic health, rather than outdated emphases on total fat, saturated fat, or calorie counting. Major questions remain, including the health effects of specific minor fatty acids, different dairy foods, phenolic compounds, other trace bioactives, and different cooking and processing methods; the influence of maternal-fetal exposures, diet-microbiome interactions, and sleep duration and quality; the mechanisms and drivers of long-term weight homeostasis; and the optimal agricultural and food systems to create healthful foods while maximizing sustainability and minimizing disparities. Yet, abundant evidence exists to define and implement specific food-based priorities as well as effective behavior change strategies, supportive health systems enhancements, and robust, complementary population policies. The ACC and all cardiologists must take the lead in translating this modern knowledge into action.

  1. Murray CJ, Atkinson C, Bhalla K, et al. The state of US health, 1990-2010: burden of diseases, injuries, and risk factors. JAMA 2013;310:591-608.
  2. Lim SS, Vos T, Flaxman AD, et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2013;380:2224-60.
  3. Mozaffarian D. Chapter 46. Nutrition and Cardiovascular Disease and Metabolic Diseases. In: Mann DL, Zipes DP, Libby P, Bonow RO, eds. Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 10th ed. Philadelphia: Elsevier/Saunders; 2014.
  4. Artinian NT, Fletcher GF, Mozaffarian D, et al. Interventions to promote physical activity and dietary lifestyle changes for cardiovascular risk factor reduction in adults: a scientific statement from the American Heart Association. Circulation 2010;122:406-41.
  5. Spring B, Ockene JK, Gidding SS, et al. Better population health through behavior change in adults: a call to action. Circulation 2013;128:2169-76.
  6. Mozaffarian D, Afshin A, Benowitz NL, et al. Population approaches to improve diet, physical activity, and smoking habits: a scientific statement from the American Heart Association. Circulation 2012;126:1514-63.
  7. Afshin A, Penalvo J, Del Gobbo L, et al. CVD prevention through policy: a review of mass media, food/menu labeling, taxation/subsidies, built environment, school procurement, worksite wellness, and marketing standards to improve diet. Curr Cardiol Rep 2015;17:98.
  8. Lloyd-Jones DM, Hong Y, Labarthe D, et al. Defining and setting national goals for cardiovascular health promotion and disease reduction: the American Heart Association’s strategic Impact Goal through 2020 and beyond. Circulation 2010;121:586-613.
  9. American College of Cardiology, Press Office. ACC Brings Health Leaders Together to Discuss Prevention of Heart Disease: Two-day Population Health Retreat will inform broad prevention agenda (ACC website). 2015. Available at: Accessed: 9/19/2015.
  10. Mozaffarian D. Diverging global trends in heart disease and type 2 diabetes: the role of carbohydrates and saturated fats. Lancet Diabetes Endocrinol 2015;3:586-8.
  11. Mozaffarian D, Ludwig DS. The 2015 US Dietary Guidelines: Lifting the ban on total dietary fat. JAMA. 2015;313:2421-2.
  12. Moran B. Is Butter Really Back? Clarying the facts on fat (Harvard T.H. Chan School of Public Health Magazine website). 2014. Available at: Accessed: 5/29/2015.
  13. Mozaffarian D, Hao T, Rimm EB, Willett WC, Hu FB. Changes in diet and lifestyle and long-term weight gain in women and men. N Engl J Med 2011;364:2392-404.
  14. Dietary Guidelines Advisory Committee. Scientific Report of the 2015 Dietary Guidelines Advisory Committee: Advisory Report to the Secretary of Health and Human Services and the Secretary of Agriculture ( website). 2015. Available at: . Accessed: 3/25/2015.
  15. National Heart Lung and Blood Institute, National Institutes of Health. WE CAN! Ways to Enhance Children’s Activity and Nutrition: Choosing Foods for Your Family (NHLBI website). 2010. Available at: . Accessed: 4/30/2010.
  16. Smith JD, Hou T, Ludwig DS, et al. Changes in intake of protein foods, carbohydrate amount and quality, and long-term weight change: results from 3 prospective cohorts. Am J Clin Nutr 2015;101:1216-24.
  17. Ludwig DS, Friedman MI. Increasing adiposity: consequence or cause of overeating? JAMA 2014;311:2167-8.
  18. Bazzano LA, Hu T, Reynolds K, et al. Effects of low-carbohydrate and low-fat diets: a randomized trial. Ann Intern Med 2014;161:309-18.
  19. Bueno NB, de Melo IS, de Oliveira SL, da Rocha Ataide T. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. Br J Nutr 2013;110:1178-87.
  20. Shaw FE, Asomugha CN, Conway PH, Rein AS. The Patient Protection and Affordable Care Act: opportunities for prevention and public health. Lancet 2014;384:75-82.
  21. Ingram R, Scutchfield FD, Costich JF. Public health departments and accountable care organizations: finding common ground in population health. Am J Pub Health 2015;105:840-6.
  22. Mozaffarian D, Rogoff KS, Ludwig DS. The real cost of food: can taxes and subsidies improve public health? JAMA 2014;312:889-90.
  23. McGill R, Anwar E, Orton L, et al. Are interventions to promote healthy eating equally effective for all? Systematic review of socioeconomic inequalities in impact. BMC Public Health 2015;15:457.
  24. Mozaffarian D, Blashek JA, Stavridis J. Learning from soft power. BMJ 2015;351:h4645.
  25. The Nutrition Source (Harvard T.H. Chan School of Public Health website). 2015. Available at: Accessed: 9/22/2015.
  26. Friedman School of Nutrition Science & Policy. Tufts Health & Nutrition Letter. 2015. Available at: Accessed: 9/22/2015.
  27. Mozaffarian RS, Lee RM, Kennedy MA, Ludwig DS, Mozaffarian D, Gortmaker SL. Identifying whole grain foods: a comparison of different approaches for selecting more healthful whole grain products. Public Health Nutr 2013;16:1-10.

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Is Keto Bad for Your Heart?

Clinical Contributors to this Story

Jacqueline Hollywood, M.D. contributes to topics such as Cardiac Care.

Renee M. Dougherty, D.O. contributes to topics such as Internal Medicine.

By Brianna McCabe

It may only be four letters, but it is one trending diet program: keto.

As the most Googled diet in 2018, keto—short for ketogenic—has been adopted by celebrities such as Halle Berry, Kourtney Kardashian and Lebron James and has since gained traction on social media.

Now if your Instagram feed looks anything like mine, I’m sure you can’t go a day without scrolling past a picture of some kind of bacon-wrapped meat stuffed with cheeses accompanied by the hashtag #ketofriendly. With each post, though, my brain always ponders:

  • What is the science behind keto?
  • Is it really that healthy?
  • So, you’re saying I can eat an entire block of cheese for dinner?
  • Isn’t all of this fat a cardiologist’s nightmare?

Two Hackensack Meridian Health Medical Group physicians help to digest this fat-packed diet.

What makes the keto diet different?

All humans require three main macronutrients: carbohydrates, lipids (fats) and proteins. It is generally recommended that the standard American consumes 45-65% of calories from carbohydrates, 20-25% from fats and 10-15% from proteins.

“The keto diet, though, significantly slashes this percentage of carbohydrates while boosting fats,” explains Renee Dougherty, D.O., board certified in internal medicine. Instead, a person might consume 5% of calories from carbohydrates, 75% from fats and 20% from proteins—though there are some individuals who might take a more aggressive approach and increase fat consumption to 90% and shift the remaining 10% accordingly, notes Dr. Dougherty.

Is too much fat bad for the body?

“If you remember back in the ‘90s, the Atkins diet was all the craze,” recalls Jacqueline Hollywood, M.D., board certified in cardiology and nuclear cardiology. “This is the low-carb Atkins diet, but with a twist.”

According to Dr. Hollywood, who has tried the keto diet in the past and noticed temporary weight loss, the Atkins diet encourages people to focus on fats—but bad fats. Keto, on the other hand, sometimes encourages much ‘cleaner’ and ‘leaner’ fats depending on the individual’s take on it, she adds.

What are the different types of fats?

“Not all fats are created equal,” advises Dr. Dougherty. Fats are broken down into three main categories: unsaturated (or “good”) fats, saturated fats and trans fats.

“A clean keto diet incorporates more of a Mediterranean diet filled with unsaturated fats, such as vegetable oils, nuts and seeds and some fish,” says Dr. Hollywood.

There are two main types of unsaturated fats: monounsaturated fats, which help lower cholesterol and blood sugar (found in foods such as avocadoes and olive oil), and polyunsaturated fats, which are necessary for proper body functioning (found in foods such as salmon and tuna).

Conversely, saturated fats are found in red meats and dairy products, such as butters and cheeses. “A diet high in these bad fats, like the ‘dirty’ keto, can increase cholesterol and ultimately lead to heart disease,” says Dr. Hollywood. “I’ve stumbled on blog articles discussing how people eat salami, pork rinds and cheeses and have lost weight through ketosis—but this is extremely detrimental to health in the long-run.”

Then there’s trans fats, which are found in processed snacks and baked goods, adds Dr. Hollywood.

An increase in fats—though both Dr. Dougherty and Dr. Hollywood agree should be mostly “good”—and decrease in carbohydrates puts your body into a metabolic state of ketosis.

What is the science behind ketosis?

According to Dr. Dougherty, this process—which can take several days—occurs when the body burns off fats instead of carbohydrates. “The liver will produce ketone bodies from stored fats which essentially acts as an alternative energy source,” she says.

So what foods should I eat?

Some cleaner keto-friendly food options include:

  • Eggs
  • Lean poultry and fish
  • Nuts and seeds
  • Nut butters such as peanut, almond and cashew
  • Healthy fats from coconut oil, olive oil and avocado oil
  • Avocados
  • Non-starchy vegetables including broccoli, tomatoes, mushrooms and peppers

Keto-friendly foods that you can eat, but in moderation, include:

  • Red meats
  • High-fat dairy products including cream cheese and sour cream

And what foods should I avoid?

Foods you cannot eat on the keto diet include:

  • Fruit
  • Grains and starches including rice, oats, corn, quinoa and wheat
  • Root vegetables such as potatoes, carrots and yams
  • Grain products such as cereal, bread and pasta
  • Legumes such as black beans, kidney beans, pinto beans and chickpeas
  • Low-fat dairy

Being that there is such an emphasis on fat, is this diet heart healthy?

Because the diet relies heavily on fat consumption, there may be an increased risk in cardiovascular disease for those consuming large amounts of saturated and trans fat, notes Dr. Dougherty.

However, with an emphasis on “good” fats, Dr. Hollywood says that a clean keto diet in the short-term can jumpstart a diet program—which can ultimately reduce risk factors of heart disease.

“When you pull carbs and sugars from your diet, you end up pulling a lot of water weight which results in weight loss,” shares Dr. Hollywood. “Weight loss can lead to improvements in blood pressure, cholesterol and lowering the risk of diabetes. All of these modifiable factors interconnect, which can help boost your heart health.”

Are there potential risks associated with the keto diet?

Individuals following a keto diet tend to avoid certain fruits and vegetables, as they are generally high in carbohydrates. “Therefore certain nutritional deficiencies may be seen,” says Dr. Dougherty.

Should any individuals chat with a doctor before trying to follow a keto diet?

Any patient with a history of heart disease and/or is on medications needs to discuss any diet plans with his or her physician(s), says Dr. Hollywood, as a drastic change in diet may affect the way the medication supports the body.

Does keto work for weight loss?

Dr. Hollywood says that she did notice weight loss while following the diet, but once she started to reincorporate carbs, she gained the weight back.

“I’d encourage those following a keto diet to consult his or her primary care doctor or nutritionist for a transition plan to sustain this weight loss and welcome back proteins and carbs,” she recommends.

However, Dr. Hollywood warns that it is important to be mindful of these ‘extreme’ diet programs, like an aggressive carb-conscious keto. “The ‘all or nothing’ phenomenon I’ve found is not that practical and not that sustainable—and individuals can develop unhealthy relationships with food,” she says.

What kind of relationship should you have with food?

“An individual’s goal should instead be embracing a lifestyle change instead of a diet, which is more sustainable over a long period of time,” expresses Dr. Dougherty. A well-balanced diet, which is high in vegetables and lean meats and low in processed foods, in addition to portion control and daily physical activity has more evidence for success, she adds.

Dr. Dougherty is located at a primary care practice in Tinton Falls and Dr. Hollywood is located at a cardiology practice in Fort Lee and is a cardiologist from the Heart and Vascular Hospital at Hackensack University Medical Center. To find a provider near you, visit To learn more about cardiovascular services at Hackensack Meridian Health, visit

The material provided through HealthU is intended to be used as general information only and should not replace the advice of your physician. Always consult your physician for individual care.


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What Causes Heart Disease?

The true evidence of what causes heart disease is finally coming to light, and it’s not the evil cholesterol and saturated fat in our diets. You may be surprised at the list below, but there is a great deal of real research in Pubmed which backs up the information in the list below.

I’ll also note below that a ketogenic diet improves the risk factors for heart disease.

What Causes Heart Disease: The Main Players

Wheat consumption. Surprised? Unconvinced? Okay, take a look at Denise Minger’s analysis of the data from the China Study here. Or you can read this study, in which the authors wrote: “The consumption of wheat flour…was positively correlated with all three diseases .”

A diet high in carbohydrates. More and more research is pointing to a high carb diet as one of the main factors in what causes heart disease. Here’s why. Eating lots of carbohydrates on a daily basis has the following effects on heart health:

  • Elevates blood glucose levels and in turn, increases circulating insulin levels, contributing to insulin resistance. High blood glucose is inflammatory and damages body tissues through glycation of the protein structures (think of what pouring maple syrup on a keyboard would do to its performance). See this paper and this paper.
  • Increases your risk of coronary heart disease and mortality through the ravages of high blood sugar. See this study and this study and this paper.
  • Elevates triglyceride levels. High levels of triglycerides are strongly associated with heart attack risk. increases the prevalence of small, dense, glycated LDL cholesterol in the blood (that’s the dangerous kind). See this paper and this paper.
  • Reduces blood levels of healthy HDL cholesterol. Low levels of HDL are associated with a higher risk of atherosclerosis.
  • Increases the risk of the development of Metabolic Syndrome, which is characterized by the presence of elevated fasting glucose, low HDL cholesterol, high LDL cholesterol, high triglycerides and high fasting insulin. See the vicious circle there?
  • Elevates blood levels of lipoprotein(a), a cholesterol derivative of LDL highly associated with heart attack risk.
  • Increases insulin resistance and the risk of diabetes, both of which are highly correlated with heart disease risk increase.

Other Causes of Heart Disease

  • Oxidized LDL cholesterol associated with a high polyunsaturated fat consumption (i.e., too much vegetable oil in the diet): Polyunsaturated oils are highly unstable and inflammatory and increase both Lp(a) and oxidized LDL within the body. This includes fish oil capsules, which are high in polyunsaturated fatty acids. See this study which showed that men who took fish oil capsules over an extended time period showed a greater risk of cardiac death, and especially sudden cardiac death.
  • Copper deficiency in the body: see this post.
  • Low Vitamin D levels: Vitamin D has so many roles in the body, that a lack of it effects not only the heart but every other body system. For specifics on heart function effects, see this study and this study.
  • Low Magnesium Levels: Magnesium plays a critical role in cellular respiration, muscle strength and nerve function, and a magnesium deficiency is highly correlated with heart dysfunction.
  • Lack of exercise: a sedentary lifestyle contributes to insulin resistance and weakened muscles. Remember, the heart is a muscle.
  • Hypothyroidism: Low thyroid function is associated with increased heart problems.
  • Smoking: smoking reduces the availability of oxygen to the body systems. Hence the heart receives less oxygen than it needs to pump efficiently, and it results in damage to the heart muscles cells.
  • CoQ10 deficiency: CoQ10 or ubiquinol is a critical substance needed by the body for cellular respiration. The body makes it, but as we age, it makes less. In addition, statin drugs prescribed to lower cholesterol deplete this substance, and the result is an increase in cardiomyopathy.

In a nutshell, all the factors above increase body inflammation. Chronic inflammation is highly correlated with not only what causes heart disease, but all kinds of body disease causes.

How a Ketogenic Diet Reduces the Risk of Heart Disease

A high fat, ketogenic diet naturally provides more copper, vitamin D, magnesium and selenium because the foods it emphasizes are higher in those nutrients.

In addition, a ketogenic diet improves the metabolic markers for heart disease risk. It’s that simple. When the carbohydrate intake is lowered, and saturated fat intake is increased, this is what happens to the body risk markers:

  • Blood glucose levels drop, reducing glycation and the proliferation of advanced glycation tissue damage
  • Triglyceride levels drop
  • Small, dense LDL become the large, fluffy non dangerous kind
  • HDL cholesterol levels increase
  • Blood glucose and insulin levels are reduced
  • Metabolic syndrome factors are improved
  • Lipoprotein (a) levels are reduced
  • Insulin levels drop, which results in less insulin resistance, and greater insulin sensitivity

For the research evidence, see this study, this study, this study, and this study. Or you can test it on yourself. If you have any of these health issues, get a baseline blood test, then go on a ketogenic diet for a month, and then get another blood test. See what your numbers do, and decide for yourself what causes heart disease.

Sources for Further Reading

Here’s a much longer list of the many studies which DON’T support the Diet Heart Hypothesis. The links below offer more information as well.

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Done with What Causes Heart Disease, back to Causes of Coronary Heart Disease

Heart disease is the leading cause of death in the world (that’s right — the entire world).

It’s the biggest public health issue in America, with heart disease numbers growing every year.

Researchers cite all kinds of different culprits in heart disease: cholesterol levels, blood sugar, inflammation, obesity, and — perhaps above all else — eating too much fat.

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Dietary fat has been villainized for years as the number one cause of heart disease, and many people still shy away from a high-fat keto diet for fear that eating saturated fat will lead them straight to a heart attack.

But more and more research shows that a high-fat, low-carb diet like the ketogenic diet won’t increase your risk of heart disease.

In fact, eating a keto diet can reverse a lot of risk factors for heart disease, including high blood pressure, type 2 diabetes, insulin resistance, triglyceride levels, excess body fat, and more.

Here’s what you need to know.

What is Heart Disease?

Heart disease is the leading cause of death for both men and women in the U.S., with coronary heart disease (CHD) causing about 50% of deaths.

CHD is caused by a buildup of plaque in the walls of your arteries, which supply blood, oxygen and nutrients to your heart and other parts of your body.

Think of plaque as a waxy substance that builds up in layers like the plaque on your teeth. The plaques that can form in your arteries are made up of cholesterol, fat, calcium, and other substances.

In a process known as atherosclerosis, the plaques keep growing bigger, and can eventually begin to narrow and block blood flow your heart and around your body.

Eventually, your heart muscle will begin to weaken which can lead to heart failure, a condition where the heart can no longer pump normally.

When the blood flow to your heart becomes blocked enough, you have a heart attack.

For a long time, dietary fat was one of those risk factors for plaque formation. But new research shows that’s probably not the case.

Does The Keto Diet Cause Heart Disease?

The idea that the keto diet can cause heart disease is tied to the thought that dietary fat is bad for your heart. Here’s how that idea came about.

Back in the 1970s, correlational research linked saturated fat consumption to heart disease. That means that in huge worldwide datasets, it looked like people who ate more saturated fat had more heart attacks.

They did not take into account other lifestyle factors like exercise and smoking.

Scientists put forth a theory: eating saturated fat increases your LDL (“bad”) cholesterol, which clogs your arteries and eventually leads to arterial plaques.

The American Heart Association (AHA) jumped on board and put out warnings against consuming saturated fats from sources like meat, butter, and coconut oil.

And thus began the low-fat diet craze. It was good-bye butter and meat, and hello fat-free dairy and low-fat pre-made meals.

But as the American diet went from high-fat to low-fat, an interesting trend happened: Even when Americans drastically decreased their fat consumption, obesity skyrocketed. In fact, from 1988 to 2008 the number of people in the United States that are obese doubled.

The connection between obesity and heart disease is clear and very strong. Risk factors for heart disease such as blood pressure, blood lipids, and inflammation all increase as obesity increases.

So in effect, as Americans stopped eating fat to protect their hearts, they unknowingly increased their risk for heart disease.

But there must have been some compelling research to make the AHA put out such strong warning, right?

Not so much. More recent research shows that there isn’t actually much of a link between saturated fat and heart disease, or fat intake in general and heart disease.

In 2010, a group of researchers did a meta-analysis on saturated fat and heart disease.

They took all the existing studies to-date and looked at them as a whole. They concluded that there’s no benefit in switching out saturated fat with unsaturated fat.

In fact, eating more unsaturated fat increased the risk for heart disease if the polyunsaturated fats were mostly omega-6 (from vegetable oils, margarine, and so on), without enough omega-3s to balance them out.

As science progresses, it’s becoming clearer and clearer that there’s no meaningful link between saturated fat consumption and risk of heart attack.

What about cholesterol and heart disease?

What’s The Deal With Cholesterol and Heart Disease?

When you hear that someone has high cholesterol, your mind most likely goes right to heart disease. Cholesterol and heart disease have been linked together so intimately that sometimes one feels like a synonym for the other.

Replacing saturated fat from meat and butter with unsaturated fat from vegetable oil does lower your cholesterol.

However, much like what happened with saturated fat, the cholesterol-heart disease connection has been poorly understood and even more poorly explained.

Both the size of the LDL particle and the number of particles seem to play a more significant role in the development of heart disease — as opposed to the mere presence of LDL cholesterol in your blood.

In other words, there’s good LDL and bad LDL.

Smaller, more dense LDL particles have a stronger correlation to heart disease than the big fluffy LDL particles. This is because the smaller LDL particles can more easily get into your artery walls and contribute to the plaques that eventually lead to heart disease.

So how do you make sure your LDL particles are nice and fluffy? Research has shown that the ketogenic diet decreases atherogenic dense LDL and increases the larger, fluffier LDL particles that are less likely to contribute to plaques on your artery walls.

3 Reasons The Keto Diet is Heart-Healthy

Some of the biggest risk factors for heart disease are:

  • Insulin resistance (and, if insulin resistance goes unchecked, type II diabetes)
  • Inflammation
  • Obesity

Let’s take a look at these heart disease risk factors and see how the keto diet affects each of them.

#1: A Ketogenic Diet Reverses Insulin Resistance and Type II Diabetes

There’s a strong correlation between insulin resistance and type II diabetes and the risk of heart disease. In fact, the AHA considers diabetes to be one of the seven major risk factors for developing heart disease.

Here’s the connection — When you have insulin resistance (or diabetes), you have too much glucose (sugar) roaming around your bloodstream.

Over time, that excess glucose can damage your blood vessels along with the nerves that control your blood vessels. This can ultimately lead to heart disease.

People who are 65 or older with diabetes have a 68% chance of dying from heart disease.

Eating a keto diet is one of the best things you can do for insulin resistance or diabetes.

By avoiding carbohydrates that turn into excess sugar in your blood, you’re protecting your blood vessels from the potential damage that blood glucose can cause, which in turn protects you from heart disease.

A keto diet is so good at reducing blood sugar levels that many people are able to come off of their diabetes medications entirely. That makes a major difference when it comes to heart disease risk.

#2: A Ketogenic Diet May Reduce Inflammation

More and more research suggests that inflammation plays a big role in heart disease.

New studies suggest that inflammation may damage your arterial wall and cause cholesterol to oxidize in your arteries, forming plaques that drive heart disease.

Your level of C-reactive protein, an inflammatory marker, is a strong risk factor for heart disease.

Research on keto and inflammation is still young. That said, the preliminary research is promising. Several animal studies have found that keto is great for decreasing chronic inflammation.

In one study, rats were fed a ketogenic diet for 14 days. At the end of the 14 days, they showed a significant drop in chronic inflammation, as well as decreased peripheral and brain inflammation.

Ketones themselves may have anti-inflammatory properties. Specifically, beta-hydroxybutyrate — one of the main sources of fuel you use on ketosis — causes a dramatic decrease in inflammatory response.

#3: A Ketogenic Diet is Great for Weight Loss and Fights Obesity

Obesity is one of the major contributors to heart disease.

The correlation comes not just from the increased body fat itself, but from factors that come along with obesity like increased blood pressure, risk of stroke, and diabetes.

Obesity is also linked to a large left heart ventricle, which is a common cause of heart failure.

If you’re looking to lose some weight, the ketogenic diet is an excellent option. You’ll not only shed extra pounds, but your hunger will also diminish so you won’t be walking around craving sugar.

A study of more than 19,000 obese patients found that a keto diet was the best way to cause rapid weight loss.

Even better, when researchers followed up with the participants a year later, close to 85% of those who lost weight had kept the weight off.

That’s very rare — most people gain weight back — and it speaks to how sustainable a ketogenic diet is. Researchers reported no adverse effects and determined that the keto diet was a safe, effective, and inexpensive treatment for obesity.

Is Keto Healthy If You Already Have Heart Disease?

The keto diet is looking pretty good for preventing heart disease, but what if you already have heart disease or are at risk?

Eating a keto diet can reverse or decrease a lot of risk factors for heart disease, including inflammation, high blood lipids, obesity, high blood pressure, and insulin resistance/diabetes — all factors you want to control if you have heart disease,,,.

That said, not all keto diets are created equal. If you’re going to try keto, make sure you choose a high-quality keto diet that’s rich in healthy fats and full of low-carb vegetables that provide an abundance of nutrients, including fiber, omega-3s, and an array of micronutrients.

Stay away from processed omega-6 oils and trans fats.

While there’s no evidence that a ketogenic diet is harmful to your heart, eating a poor quality diet full of processed foods and trans fats can definitely impact your heart health — whether it’s low-carb or not.

So keeping your keto diet clean and healthy is just as important as keeping your carbs low.

And, of course, if you are planning on trying a new diet you should always consult with your health care practitioner.

The Takeaway: Does Keto Cause Heart Disease?

Plain and simple, the keto diet does not cause heart disease.

In fact, following a low-carb, high-fat diet may be one of the best ways to prevent heart disease.

The anti-inflammatory, blood sugar regulating, bad cholesterol lowering, and anti-obesity effects of the ketogenic diet all make it a great option for decreasing your risk of heart disease.

Ready to try the ketogenic diet? Try the Keto Kickstart — a simple 30-day challenge to get you into ketosis, quickly and painlessly.

Can the Keto Diet Help Prevent or Manage Heart Disease?

Some keto followers brag about how much butter and bacon they can eat. So, if you have heart disease, are at risk for it, or are generally concerned about your heart health, you may be confused about whether the diet — made up of at least 70 percent fat and very few carbs, depending on the version of keto you follow — could be for you. The short answer is that you may be able to try the keto diet, but only under close supervision with a keto-knowledgeable doctor (and, ideally, a registered dietitian as well). For optimal heart health, many cardiologists are wary of the keto meal plan.

RELATED: Does the Ketogenic Diet Work for Type 2 Diabetes?

What Are the Possible Heart Health Benefits of the Keto Diet?

The heart’s scourge is inflammation, which injures arteries, says Audrey Fleck, RDN, an integrative and functional dietitian nutritionist and certified diabetes educator in Perkasie, Pennsylvania. “Many times, the cause of inflammation is elevated blood sugar,” she says. What’s more, a keto diet may help lower blood sugar and improve insulin function, and can be anti-inflammatory, she says. Insulin is a hormone that helps regulate blood sugar levels.

But the specific foods you choose on keto matter, too. In a study published in September 2010 in the Annals of Internal Medicine on women and men who followed a low-carb diet, those who heavily relied on animal sources of fat and protein, such as cheese and meat, had a 43 percent higher risk of mortality compared with those who emphasized vegetable sources, such as avocado and nuts, for those nutrients. Those in the veggie low-carb group had a 20 and 23 percent lower risk of early death and heart disease, respectively.

A review in the May 2017 issue of the journal Nutrients examined the effects of keto on the heart by looking at both rodent and human studies. In humans, the authors noted, research has shown that total cholesterol, triglycerides, and LDL (“bad”) cholesterol often decrease on keto, while “good” protective HDL cholesterol increases. Blood sugar and HbA1C (which is a two- to three-month average of blood sugar levels) also tend to go down, possibly offering protection against prediabetes and type 2 diabetes.

But human studies have shown mixed results about whether the keto diet increases or decreases insulin resistance or insulin sensitivity. And while people may lose weight on keto, the key is maintaining that loss, and that’s not a given. The researchers also note that there isn’t a strict definition of keto across the board that studies are using, so it’s tough to even know if the participants reached ketosis in the first place.

RELATED: What Are the Possible Benefits and Risks of the Keto Diet?

What to Know About Keto if You Want to Help Prevent Heart Disease

There is a lot of talk about the dangers of eating sugar when it comes to your heart. (By sugar, we’re talking simple, processed carbs.) Indeed, “eating a diet high in sugars can lead to insulin resistance, weight gain, and (down the line) metabolic syndrome,” which increases the risk of heart disease, says Suzanne Steinbaum, DO, the director of women’s heart health prevention and wellness at Mount Sinai Hospital in New York City. It was the ’80s and ’90s that some touted going low- or no-fat, she says, but then a funny thing happened: “People gained weight eating more carbs and sugar.” Today, with the popularity of keto, the pendulum has swung in the other extreme direction, into high-fat and low-carb.

If there’s anything to be learned there — and this is what Dr. Steinbaum wants everyone to hear if they’re looking to reduce their risk of heart disease — it’s this: “I promise, there is a place that lies in between low-fat and high-fat. And that’s a Mediterranean diet filled with good fats like omega-3s from fish and unsaturated fats from avocado and nuts, but also fiber-rich whole grains,” she says.

RELATED: What Are the Best and Worst Fats to Eat on the Ketogenic Diet?

Warnings About the Keto Diet if You’re at Risk for Heart Disease

If you’re at risk for heart disease (factors include having high blood pressure, high cholesterol, or prediabetes or type 2 diabetes, or if you are overweight or obese, according to the National Heart, Lung, and Blood Institute), one overarching factor to consider is that the keto diet is restrictive, and it’s tough to stick to a restrictive diet, says Steinbaum. “People go on keto and in the short term lose a lot of weight, but it’s not sustainable. So when they go off it, they gain the weight back — and maybe even more,” she says.

Yo-yo dieting can put stress on the heart. One large study in the October 2018 issue of the journal Circulation found that people who have the greatest variability in measures like fasting blood glucose, cholesterol, blood pressure, and body weight are 2.3 times more likely to die from any cause, and more than 40 percent more likely to suffer a heart attack or stroke compared with those who stay more stable. Staying stable in these measurements is healthier than constantly going up and down. (Of course, this doesn’t mean that you shouldn’t try to reach a healthy weight, only that restrictive diets that lead to loss and regain can make you worse off than when you began.) “Ultimately what you’re doing is setting yourself up for developing metabolic syndrome,” says Steinbaum.

RELATED: Yo-Yo Dieting Associated With Early Death, Study Finds

What’s more, lifestyle factors aren’t the only thing that affects your likelihood of developing heart disease. There’s a genetic component, too. Particularly for people with a family history of the disease, genes may affect their ability to metabolize fats. “If you’re one of those people, a keto diet can make the situation significantly worse. This isn’t just about weight loss. It’s about your metabolism on a cellular level, and you can be doing yourself much more harm than good.” Translation: Keto may increase your risk for heart disease if the condition runs in your family.

One concern is the effect a keto diet has on cholesterol levels. As an article in the Harvard Health Blog explains, data shows that cholesterol may spike when you first start a keto diet but then decrease after a few months of ketosis. The author points out something critical: There isn’t long-term research showing what happens to cholesterol levels. And that uncertainty matters — especially when we’re talking about your heart health.

RELATED: 10 Surprising Facts About Cholesterol

Is the Keto Diet a Good Choice if You’re Living With Heart Disease?

If you have heart disease, you need to be working closely with your cardiologist to make the best heart-healthy lifestyle changes for you. In terms of your diet, your doctor may recommend the Mediterranean diet — not keto.

One study published in April 2016 in the European Heart Journal looked at 15,482 patients with stable heart disease and asked them questions about their diets. After a four-year follow-up, those who more closely followed the Mediterranean diet had a lower risk of a heart attack or stroke compared with those on a “Western diet” (higher in refined grains and sugars and fried foods). The researchers concluded that adding these healthier foods, which include sources of carbs banned on keto — fruits, veggies, legumes, and whole grains — rather than avoiding unhealthy foods (sweets, for instance) was the most important factor in preventing another heart problem.

In an analysis for the American College of Cardiology in May 2016, which was geared toward an audience of cardiologists, Dariush Mozaffarian, MD, a cardiologist and professor of nutrition at Tufts University in Boston, advised doctors to wade through the trendy diets, including low-carb diets, noting that these have a “minor or uncertain influence on health.” He adds that the Mediterranean diet comes the closest to an evidence-based diet that hits the mark.

RELATED: 10 Easy Mediterranean Diet Swaps to Make Today

The Bottom Line on the Relationship Between Keto and Heart Disease

Heart disease development is based on multiple factors, including blood pressure, cholesterol, blood sugar, family history, smoking, and stress, says Steinbaum. Your diet, while important, “is just a piece of the story,” she says. “Ultimately, it’s not about keto. It’s not about eating sugar. People may want to follow this diet because it makes them feel in control, but nothing is such a quick fix. It’s just not that simple,” she says.

Don’t rely on keto to prevent heart disease or treat existing heart disease. If you’re at risk, only go on a keto diet under the supervision of your doctor or cardiologist, especially if you have a family history of the disease, which, in that case, may mean a keto diet could be dangerous.

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

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