Leading Cardiologist Dr. Ibal Sebag discusses the ketogenic diet and how to maintain a low-carb lifestyle the healthy way.
Conventional wisdom may suggest that in order to avoid getting fat, one should stop eating fatty foods. But is this right? Proponents of the ketogenic diet claim that the healthiest way to eat (and a great way to lose body fat) is to consume a high-fat diet – getting about 70% of ones daily Calories from fat (whether it's saturated, unsaturated, or polyunsaturated fat). Interestingly, individuals following this seemingly backward way of eating are reporting both health benefits and weight loss. So what’s the deal? We’ve asked Dr. Igal Sebag, leading cardiologist at the Medisys Preventive Health Clinic in Montreal and Associate Professor of Medicine at McGill University, to weigh in on the ketogenic diet craze and to discuss who this diet might be right for.
Q: What is the ketogeic diet and how does it compare with the conventional “healthy balanced diet”?
A: To put it simply, there are three food sources of calories in the human diet: protein, fat, and carbohydrates (alcohol contains calories, but is considered a drug not a food). A traditional "healthy balanced diet" is made up of a balance of protein, fat, and carbs. The average Canadian today, however, gets more than 65% of their daily calories from carbohydrates, about 20% or less from protein, and about 15% or more from fat – including saturated fat and unsaturated fat. Unfortunately, the majority of Canadians eat mostly “bad carbs” (eg. free sugars, white bread, processed foods, fruit juice, pop, French fries, pastries etc.) instead of “healthy carbs” (like whole fruit, legumes, sweet potatoes, whole grains, etc.). Even more alarming, some reports suggest that many Canadians (especially kids) are getting about half of their daily calories from refined sugar! Consequently, the rates of chronic diseases like type II diabetes, heart disease, and obesity are rising dramatically in this country.
The traditionally accepted “healthy balanced diet” among the medical and dietitian community (although nothing is set in stone) typically includes about 50% good carbohydrates (focusing on vegetables, whole fruit, whole grains, legumes etc.), 30% protein (focusing on lean meats, nuts, seeds, eggs, and dairy products), and up to 20% fats (focusing on unsaturated and polyunsaturated fats and limiting saturated animal fats). The ketogenic diet is a high fat diet where carbohydrate consumption is severely restricted (often to about 20 grams of total carbohydrates per day - or 5% of total calories); protein consumption is somewhat restricted, and fats are eaten in abundance. The goal of the ketogenic diet is to lower glucose and glycogen levels in the body so that it is forced to burn protein and stored fat for fuel instead. In metabolizing fat and protein for fuel the body produces molecules called “ketone bodies”; a state known as “ketosis”. To achieve “ketosis” the ketogenic diet often recommends that a maximum of 5% of daily calories should come from carbohydrates, with the rest coming from protein (25-30%) and fat (65-70%). The ketogenic diet is somewhat similar to a conventional low-carb diet, in that both diets severely restrict carbohydrates. However, most low-carb diets (such as the Atkins diet) focus on eating more protein, whereas the ketogenic diet focuses on eating more fats.
Looking for healthy low-carb diet ideas? Download the complete low carb diet guide.
Q: Why is the ketogenic diet controversial among Cardiologists?
A: For optimal cardiovascular health, the medical and dietitian community has typically encouraged limiting saturated animal fat intake to no more than about 7% of daily calories, (that’s less than 20 grams of saturated fat for a typical healthy adult consuming about 2000 calories/day) and < 200 mg/d of dietary cholesterol. A number of peer-reviewed studies have confirmed that - with all other things being equal - limiting consumption of saturated fat and dietary cholesterol helps lower ‘bad cholesterol’ (LDL cholesterol) levels in the blood and helps reduce the risk of developing cardiovascular disease. The World Health Organization’s systematic review reported that healthy low saturated fat diets (eg. the Mediterranean diet, the MIND diet, or plant based diets) are associated with decreased combined cardiovascular events compared with high saturated fat intake diets. That said, individuals who follow a low-saturated fat diet but at the same time consume high amounts of refined carbs, do not achieve the same health benefits. Often individuals following the ketogenic diet do not distinguish between saturated animal fats like lard, chicken fat, duck fat, goose fat, butter, heavy cream, fatty red meat, cheese etc. and “healthy fats” like avocados, olive oil, small wild-caught fatty fish, nuts, seeds etc. Simply put, a high fat diet can be healthy (if you eat the right keto-friendly foods) but it's still advisable to focus on healthy fats and limit unhealthy fats. This lack of distinction between good vs. bad fats among some individuals on the ketogenic diet may result in individuals consuming 10 times the daily recommended limit of saturated fat. This is a concern - particularly for individuals with certain cardiovascular disease risk factors or certain health conditions.
Q: Many people following the ketogenic diet report rapid and significant weight loss. Explain this.
A: Weight loss ultimately comes down to two things – calories consumed and calories burned. If you burn more calories than you consume by increasing physical activity – you lose weight. If you consume fewer calories than you burn by eating less – you lose weight. It’s important to note that based on the available data, almost all studied “diets” that focus on eating whole foods (vs. refined, processed foods) have been shown to induce weight loss as long as they result in an overall calorie deficit (burning more calories than one consumes). The primary reason why most diets (or dieters) fail in achieving the level of weight loss they expect is because diets are hard to stick to, so people give up. It's better to make sustainable positive changes that you can stick to long term - changes like replacing juice and pop with water, or eating an extra serving of vegetables with every meal - than to continuously cycle through different diets that you can't maintain. The ketogenic diet, the Atkins diet, the Zone diet, the Paleo diet, Weight Watchers, the Mediterranean diet, the South Beach diet, they've all actually been shown to induce weight loss if they are followed as directed. The interesting thing about the ketogenic diet, however, is that many dieters find it easier to stick to than other diets, and thus may be associated with higher rates of success.
Healthy carbohydrates and foods that are high in soluble fibre help the body absorb and retain water – which is important not only for digestion and bowel regularity, but also for other biological processes. When carbohydrates are severely restricted, as in the case with the ketogenic diet, often people lose water quickly which can give the illusion or appearance of rapid weight loss. This helps motivate people to stick with the diet until the actual health benefits and fat loss kick in. Whatever your goal, whether it's losing weight, improving your overall health, or managing a specific chronic condition, it's important to speak with a physician to understand which diet may be best for you based on your current health status and disease risk factors. In the case of the ketogenic diet, it's also important to work with an experienced registered dietitian to help you ensure that you are eating the right foods to meet your daily micro-nutrient requirements.
Q: If all diets have the potential to induce weight loss, why is the ketogenic diet specifically becoming so popular?
A: The ketogenic diet isn't just about weight loss - although weight loss is often a welcome consequence. The ketogenic diet has been investigated for its potential role in the management of numerous conditions from diabetes, to epilepsy, to mood disorders, to infertility and other health conditions. In my opinion, there is a healthy way and an unhealthy way to follow a high fat low carbohydrate diet. For people who love eating rich, heavy, satisfying foods that are not typically "allowed" on other diets (like mascarpone cheese and stilton, butter, bacon, pork belly, ribeye steaks, egg yolks, cured red meats, and whipping cream etc.) the ketogenic diet is "easy" because it may be easier to stick to than other diets. However, even though these rich, fatty foods may not break the "rules" of the ketogenic diet, they are still not healthy if consumed in large quantities. Also, if you are eating cheese and meat at the expense of vegetables, whole fruit, and nuts and seeds, than this can become a health issue.
When it comes to weight loss, relative to carbohydrates, protein and fat are digested slowly and make you feel fuller for longer. Therefore, by design, the ketogenic diet may help suppress appetite making it easier to consume fewer calories in a day than you otherwise might, without the hunger. People like diets that don’t leave them feeling hungry, hence the rising popularity. Consider the following example: let’s say you were on a Calorie restrictive diet and you wanted to limit a particular meal or snack to 400 Calories. For the purposes of illustration, here are four food options that would be within this Calorie budget:
For the purposes of illustration, here are four food options that would be within this 400 Calorie budget:
- High carb – 100 grams of rice cakes (81 grams of carbohydrates, 3 grams of fat, 8 grams of protein)
- High fat – 100 grams of bacon (1 gram of carbohydrates, 38 grams of fat, 12 grams of protein)
- High protein – 25-30 egg whites (6 grams of carbohydrates, 1.5 gram of fat, 90 grams of protein)
- Healthy balanced option – large spinach salad with avocado, grilled chicken, apple, roasted sweet potato, walnuts and an olive-oil based dressing (22 grams of carbohydrates, 24g of protein, 22 grams of protein)
Even though all above listed options contain about the same amount of total calories, the high carb option (the 100 grams of rice cakes) would likely leave you feeling hungry again after an hour or two.
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Q: Explain ketosis and the potential risks of putting your body in a chronic state of ketosis.
A: Unless you restrict carbohydrate intake, glucose from carbohydrates are the body’s primary and preferred fuel source and is essential for central nervous system function. You can’t live without at least some glucose, period. When you consume carbohydrates, your body either breaks the carbohydrates down into glucose for use as immediate fuel, or stores the glucose as glycogen for later use. When your body runs out of glucose and glycogen stores (eg. when you are on a carbohydrate restrictive diet like the ketogenic diet) your body is forced to metabolize protein and fat as an alternative source of fuel. In metabolizing fat and protein, you create “ketone bodies”, putting your body into a state of “ketosis”. For healthy individuals who don’t have diabetes and aren’t pregnant, ketosis usually kicks in after 3 or 4 days of eating less than 50 grams of carbohydrates per day (the equivalent of about 1 and 1/2 bananas). Fasting also induces ketosis. Severe ketone body buildup can lead to a condition known as “ketoacidosis” which is a serious condition that can disturb pH levels, lead to bone loss, kidney stones, kidney disease, and liver disease - or, in severe cases, coma or death. However, this condition rarely affects people do not have diabetes (primarily type I diabetes). It's important to speak with a physician to understand your personal health status and your risk factors before starting any severely restrictive diet.
Q: Is the ketogenic diet a healthy choice?
A: Short answer, yes, the ketogenic diet can be a healthy way to lose excess weight and an effective disease management tool, if done right, under the guidance of qualified health professionals. The ketogenic diet is not for everyone and that's why we recommend seeking the advice of a physician and registered dietitian prior to trying the ketogenic diet. When discussing the topic of health and healthy lifestyle choices, I think it’s important to note that (according to stats Canada) the average Canadian really isn’t very healthy at all. More than 50% of Canadians are either overweight or obese, close to one third of the Canadian population is diabetic, and 90% of Canadians have at least one risk factor for heart disease and stroke. If it were so easy to only eat whole nutritious foods and consume only the amount of calories we needed to maintain our health, we wouldn’t have an obesity epidemic and a diabetes epidemic. I recognize that most Canadians that are overweight or obese may really struggle to lose the extra weight. Some individuals claim that they’ve tried all types of other diets and that the ketogenic diet is the only one that has worked for them because it reduces their cravings for sugary and highly-processed, high carbohydrate foods. Excess weight, especially around the belly, substantially increases an individual’s risk of numerous health conditions such as diabetes, coronary heart disease, stroke, osteoarthritis, sleep apnea, several cancers, depression, and others - so for individuals with these risk factors, finding a sustainable healthy diet that works for them is important. Looking for healthy low carb diet ideas? Download the ketogenic diet guide.
Q: What does the research say about high fat/low carb diets?
A: A mounting body of evidence does suggest that higher fat and lower carbohydrate diets may be associated with improved health outcomes and a lower risk of death relative to lower fat diets. For example, a recent major global study (the PURE study) led by researchers at the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences – which followed more than 135,000 individuals for over seven years, suggested consuming about 35% of daily energy as fat is associated with a lower risk of death compared to lower fat intakes. Also, the research demonstrates that diets low in refined sugar and refined carbohydrates lead to weight loss and other health benefits. The most important thing is to focus on health, not weight. Evidence overwhelmingly shows that low-risk health behaviors (achieving and maintaining a healthy body weight, eating a healthy balanced diet, getting regular physical activity, smoking cessation, limiting alcohol consumption, and getting sufficient sleep) are immensity powerful in the prevention of heart disease. In fact, results from large observational studies suggest that low-risk lifestyle behaviors are associated with a 60%-80% lower risk of heart disease. Concerned about your health? Contact us.
Q: For individuals following the “ketogenic diet”, what would you recommend?
- Consult a Registered Dietitian to ensure your micronutrient requirements are met. High-fat, ultra-low-carb foods can often be low in water content, vitamins, minerals, fibre, and disease-fighting antioxidants. If you aren’t careful, you may risk vitamin deficiencies, constipation, electrolyte imbalances, and dehydration. An experienced dietitian will work with you to ensure that you are eating the right foods.
- Before considering a highly restrictive diet like the ketogenic diet, consult your local preventive health clinic and speak to a physician that specializes in preventive health. Get your blood work done. Understand your risk of cardiovascular disease. At Medisys, a team of Registered Dietitians, cardiologists, kinesiologists, and primary care physicians work collaboratively with you to help you achieve your health and diet goals safely.
- Focus on healthy fat sources like nuts, seeds, avocados, small fatty fish, and olive oil and limit saturated fats and dietary cholesterol.
- Try to consume some fruits or vegetables from EVERY colour category EVERY day (red, purple/blue, orange/yellow, green, and brown/white) - focusing more on vegetables than fruit. This colour variety will help guard against micronutrient deficiencies. Also, include some cardio-protective foods in your diet like soluble fibre, high anti-oxidant foods, unsweetened cocoa powder, raw nuts and legumes.
- Stay properly hydrated. Drink lots of water - if you need help try our 9 day hydration challenge.
About the author: Dr. Igal A. Sebag is an Associate Professor of Medicine at McGill University and Director of Non-Invasive Cardiology at the Sir Mortimer B. Davis-Jewish General Hospital in Montreal. He is the Founder and Director of the Medisys Heart Centre in Montreal, at the Medisys preventive health clinic.
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