One of the main concerns people have about the ketogenic diet is the amount of fat. How can eating 70-80% of your calories from fat be healthy? Isn’t all that fat going to clog your arteries? Doesn’t eating fat make you gain weight? And isn’t obesity linked to heart disease? What about all that saturated fat?
But what does the research say? Below are summaries of three studies that examined fat and heart disease.
A 2004 randomized, controlled trial compared the effects of a low carbohydrate, keto diet program to a low-fat, low-cholesterol, reduced-calorie diet program in 120 overweight volunteers with high cholesterol levels. Those on the low carb diet were told to eat less than 20 grams of carbs a day, given some nutritional supplements, recommended to exercise, and attended group meetings. The low fat group was instructed to eat less than 30% of their calories from fat, less than 300 mg of cholesterol daily, and attended group meetings for 24 weeks. The study tracked the participants: weight, body composition, lipid levels, and diet tolerability.
Conclusion: Of all the participants, 76% of the low carb group completed the study while only 57% of the low fat group completed the study. Weight loss, a decrease in triglycerides, and an increase in HDL cholesterol was seen in the low carb group. Changes in LDL did not differ between the groups. The low carb, keto diet promoted weight loss and did not increase risk of heart disease (1).
A 2012 systematic review and meta-analysis was carried out to study the effects of a low carb diet on weight loss and cardiovascular risk factors. The review looked at 23 reports from 17 clinical investigations that included 1141 obese patients. They examined: body weight, BMI, waist circumference, blood pressure, triglycerides, fasting glucose, A1c, insulin, CRP, HDL, LDL, and creatinine.
Conclusion: The low carb diet showed favorable effects on body weight and major cardiovascular risk factors (2).
A 2014 systematic review and meta-analysis examined the association of Dietary, Circulating, and Supplement Fatty Acids with coronary risk. The purpose of the review was to summarize evidence about associations between the different fatty acids (saturated, polyunsaturated, monounsaturated, and trans fat) and heart disease. Over 600,000 participants within 76 studies were analyzed.
Conclusion: Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats (3).
Research shows that low carb, high fat diets and the keto diet do not increase risk of cardiovascular disease. But don’t take our word for it. Use the links to read the studies yourself. And stay tuned for Keto Diet, Fat, and Heart Disease (Part Two).