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Healthy Weight Center

What About the Mayo Clinic Diet?



Several of my co-workers and I are on a new diet which says that "fat does not form fat." We can eat all the meat we want, are required to eat (real)bacon and eggs every morning, salad every lunch, red and green vegetables, and carrots. We are also required to drink grapefruit juice 3 times a day. The diet completely eliminates sugars and starches which they say are lipids and form fat. The diet also says it is prescribed for heart patients needing to lose weight fast for by-pass surgery. Those who have been on the diet for two weeks have lost 5-10 pounds so it does achieve the weight loss it promises. My question is, will this diet harm us and, if so, how? The plan is to stay on for 12 days at a time and them off two days. If the diet is OK for a short time, how long can we do it without harming our bodies in some way? Thanks.


Thanks for your questions. This diet has been named the "Mayo Clinic Diet". In actuality, the Mayo Clinic never developed this diet and does not support it. In addition, the American Heart Association warns consumers that these diets are dangerous and not recommended. Any fad diet that restricts certain foods or food groups, is not safe or healthy (short or long term). The weight that your co-workers lost in the 2 weeks they followed this diet was most likely water, and some muscle mass. Please see the previously answered question about high protein diets (8-12). As for "fat not making you fat", any source of calories in excess (whether they come from fat, carbohydrate or protein) will turn into fat stores if they are not utilized (i.e. burned off through exercise and normal metabolism). Fat is more calorically dense than carbohydrate or protein (9 calories per gram vs. 4 calories per gram in protein and carbohydrate). So, the more fat you eat, the more calories you consume, the more likely you'll gain weight. Grapefruit juice is a carbohydrate (and therefore a source of sugar), so this diet does not completely restrict carbohydrates. However, grapefruit juice has been touted as a "fat burner" due to its acidity. But, this is a false statement, and has never been proven; no foods "burn fat", only exercise truly "burns" fat. Another problem with this diet is that grapefruit juice can mix with certain blood pressure medications and make them toxic. Patients with heart disease that are taking certain blood pressure medications should AVOID taking the medication with grapefruit juice. I would not recommend this diet for some one awaiting by-pass or any other surgery. As I mentioned previously, when the body is in a state of starvation (due to calorie deprivation), muscle is utilized as a calorie source. Long term use of this type of diet can weaken heart muscles, and is not recommended. The weight lost initially on this diet is fluid, and not fat. A person will only dehydrate themself if they follow this type of diet. Additionally, electrolytes such as magnesium and potassium are vital to the function of a healthy heart. These minerals are lost when the body loses too much fluid. In short, crash diets can be harmful to a person with a chronic disease such as heart disease, diabetes, or high blood pressure. Also, a high fat diet INCREASES your risk of heart disease...so, this type of diet would not benefit someone awaiting open heart (by-pass) surgery. It may only exacerbate their condition long term. Again, this diet has NOT been developed or supported by the Mayo Clinic, and is not recommended by the American Heart Association. My advice is to decrease your total fat and calorie intake, invest in a good pair of walking shoes, and eat foods you like (such as bacon and eggs) in moderation (like twice a month perhaps). For additional diet information, see the American Dietetic Association Website, or the Tuft's Nutrition Navigator. Good luck to you. Sincerely, Lisa M. Cicciarello, MEd, RD, CNSD Cincinnati, Ohio

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Response by:

Kathleen Rourke, PhD, RN, RD, CHES
Formerly, Associate Dean
College of Allied Health Sciences
University of Cincinnati