‘Fad’ Diets May Do More Harm Than Good, Study Finds

‘Fad’ Diets May Do More Harm Than Good, Study Finds

Many Americans are losing weight on so-called “fad” diets – but in the process, they could be putting themselves at greater risk for developing coronary heart disease.

LEXINGTON, KY (Oct. 11, 2000) – Many Americans are losing weight on so-called “fad” diets – but in the process, they could be putting themselves at greater risk for developing coronary heart disease, according to a University of Kentucky College of Medicine study published in the October 2000 issue of the Journal of the American College of Nutrition.

A team of researchers led by James W. Anderson, M.D., professor of medicine and clinical nutrition in the UK College of Medicine, performed a critical review and computer analysis of eight popular weight-loss diets. He was joined by David Jenkins, M.D., Ph.D., professor of medicine and clinical nutrition at the University of Toronto, and Elizabeth Konz, M.S., R.D., a doctoral candidate in nutrition at UK.

Eight weight loss diets were analyzed: Sugar Busters!, Protein Power, The Zone, and Dr. Atkins’ New Diet Revolution were compared with moderate diets, Dr. Anderson’s High-Fiber Fitness Plan and the American Diabetes Association/American Dietetic Association Exchange Diet. The other two analyzed, the Pritikin Diet and the Ornish Diet, are on the opposite extreme of many of the popular diets, stressing a very low fat, high carbohydrate, vegetarian diet.

The study, which involved a critical review and computer analysis, showed several diets to be nutritionally questionable in various aspects.

The researchers found that Protein Power and Dr. Atkins’ New Diet Revolution had negative effects – raising cholesterol levels, which have been linked with an increased risk for coronary heart disease (CHD).

The Atkins and Protein Power diets were found to be the highest in total and saturated fat compared to current dietary guidelines. Long-term use of the diets likely would increase significantly serum cholesterol concentrations and risk for CHD, Anderson found.

“Of course, weight loss contributes to the lowering of cholesterol, but high-fat diets such as the Atkins diet increase the risk for heart attacks and strokes by raising LDL cholesterol – the bad stuff – and increasing the tendency for blood to form clots, which are the forerunners of most heart attacks and strokes,” Anderson said.

Higher carbohydrate, higher fiber, lower fat diets are the best at decreasing serum cholesterol concentrations and the risk for CHD and diabetes. These diets also are high in whole grains, vegetables and fruits, which also help reduce the risk for CHD, diabetes and cancer, Anderson said.

The protein content of four of the diets (Sugar Busters!, Protein Power, The Zone and Dr. Atkins’ New Diet Revolution) is almost double the recommended daily allowances. High animal protein intakes have been linked to higher risks for CHD. This high protein load may lead to kidney damage, especially in people with diabetes or high blood pressure, Anderson said.

Anderson agrees with the American Heart Association’s newly released guidelines, which found no scientific evidence to support the concept that high protein diets result in sustained weight loss, significant changes in metabolism or improved health.

“The high animal fat, high protein diets may be the most atherogenic diets that have been developed for promoting arteriosclerosis or hardening of the arteries,” Anderson said. “These are the types of diets that are fed to laboratory animals to rapidly promote atherosclerosis.”

The Atkins and Protein Power diets provide fewer servings of grains, vegetables and fruits than the minimum recommendation of 11 servings per day, and the Sugar Busters and The Zone diets hover at the recommended level, the study reported. ADA Exchange and the High-Fiber diets exceed the recommendations, and the Ornish and Pritikin diets most strongly encourage “eating at the bottom” of the food pyramid, the researchers found.

Sugar Busters! and The Zone diets weren’t found to cause any harm, but the researchers also did not find any evidence supporting the diets’ health claims.

“Overall, the best diet for general health promotion, weight loss and weight maintenance is a high-carbohydrate, high-fiber diet that is low in fat,” Anderson said.