Examines the risks of low-carbohydrate diets.
David C. Nieman, Dr.PH., FACSM, is professor and director of the Human Performance Laboratory, Appalachian State University, in Boone, NC, an active researcher, and author of several textbooks on health and fitness.
Q: I work out up to 1 hour a day, but several extra pounds of body fat stubbornly persist. Do you recommend that I switch to a low-carbohydrate diet?
A: No, especially if you value your long-term health. Let me start with this comparison: the average smoker weighs 7 lbs less than a nonsmoker, and fear of weight gain after quitting keeps many smokers puffing away. But as I teach my students, weight management through smoking comes at a stiff price-15 fewer years of life on average. Smoking is an effective method, but what is the sense of looking thin in your coffin? In the same way, the low-carbohydrate or Atkins diet will cost you much more than your outlay at the grocery store. All that saturated animal fat is slowly but surely laying down the plaque in your arteries that increases the odds of dying early from a heart attack or stroke.
Many people claim that they feel so much better on the Atkins diet, and besides, they get to eat everything they really like. Don't forget, however, that a smoker feels better when smoking a cigarette. Feelings are no criteria of truth or that you're doing what's best for your body. Just attend your local AA meeting for testimonials.
There is no doubt that some people are achieving weight-loss success on the low-carbohydrate diet. Any fad diet will help you lose weight for the short term, but if you manage to stick with the regimen over the long term, you will lose your health. Do you remember the Beverly Hills diet of the 1980s? Eating all those tropical fruits while excluding other food groups helped people lose weight, but the body's reserves of vitamins and minerals were depleted, and overall nutritional health was sacrificed.
What about the recent reports that the Atkins diet is not only effective at weight loss, but helps decrease blood cholesterol and levels of other heart disease risk factors? Let me summarize the results from recent studies comparing low-carbohydrate diets with conventional diets (low-fat, moderate- to high-carbohydrate) (1-5):
* Weight loss is similar, especially when subjects are studied for 1 year or longer.
* Both types of diets suffer from high attrition rates and poor adherence.
* Improvements in disease risk factors are similar, supporting the adage that weight loss by any means is a good thing, but only for the short term.
* Low-carbohydrate diets are high in cholesterol and saturated fat and deficient in dietary fiber and some nutrients, especially calcium, folic acid, antioxidants, and phytochemicals. Most long-term epidemiological studies indicate that this type of diet promotes heart disease, colon cancer, and osteoporosis.
Despite this evidence, and the lack of support from reputable health professionals, low-carbohydrate, high-protein and high-fat diets are all the rage right now. Of the top 10 diet books today, nearly all deal with carbohydrate restriction or "bad carbs" versus "good carbs." Leading the charge is the Atkins diet plan. The Atkins group recently submitted its new food guide pyramid, with protein sources such as beef, pork, and poultry as the foundation; the rest of the plan is devoted to helping people follow a restricted carbohydrate lifestyle.
How strange that Atkins and The Atkins Physician Council failed to acknowledge the published medical literature showing that populations with high-carbohydrate diets have low heart disease and cancer death rates, along with high life expectancies. Case examples include the Japanese, with their rice-based diets supplemented with fish and vegetables, and people living along the Mediterranean basin, who enjoy their pastas, fruits, vegetables, legumes, olives, nuts, and olive oil, while largely avoiding red meats.
Yes, we are in the midst of an obesity epidemic. Nearly 2 out of 3 people in the United States are overweight or obese, and most of our major disease killers are related to carrying extra fat. The cause is simple: people in the United States are eating too much, and exercising too little. Fad diets such as the Atkins diet are not the solution, because they postpone the ultimate decision to get one's diet and exercise habits under control. You can't live on the Atkins diet for the rest of your life, because your heart can't take it. You may lose weight for the short term with this diet, but in the end, you're facing the same habits that got you into trouble in the first place.
My own research has shown one thing: those successful at weight loss have "caloric awareness." In other words, those who lose weight and keep it off over the long term are aware of the calories they eat relative to those expended through physical activity and exercise. These individuals know how to balance the calories coming in with those going out. No gimmick diets or hocus pocus; they just work at keeping themselves under caloric control. Perhaps you have heard about the large national registry of people who have lost more than 30 lbs and kept it off for more than a year (visit http://www.lifespan.org/services/bmed/wt_loss/nwcr for more information). Nearly all report that they have decreased food intake in some way with an emphasis on a low-fat diet. Nine in ten say they exercise for about 1 hour a day.
In summary, my recommendation to you is this: never lose weight by any method that you cannot live with healthfully for the rest of your life.
1. Brinkworth, G.D., M. Noakes, J.B. Keogh, et al. Long-term effects of a high-protein, low-carbohydrate diet on weight control and cardiovascular risk markers in obese hyperinsulinemic subjects. International Journal of Obesity and Related Metabolic Disorders
2. Yancy, W.S., M.K. Olsen, J.R. Guyton, et al. A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia. Annals of Internal Medicine
3. Meckling, K.A., C. O'Sullivan, and D. Saari. Comparison of a low-fat diet to a low-carbohydrate diet on weight loss, body composition, and risk factors for diabetes and cardiovascular disease in free-living, overweight men and women. Journal of Clinical Endocrinology and Metabolism
4. Stern, L., N. Iqbal, P. Seshadri, et al. The effects of low-carbohydrate versus conventional weight loss diets in severely obese adults: one-year follow-up of a randomized trial. Annals of Internal Medicine
5. Foster, G.D., H.R. Wyatt, J.O. Hill, et al. A randomized trial of a low-carbohydrate diet for obesity. New England Journal of Medicine