Questioning the norm

Amid the fad diets and weight loss hoaxes, one piece of weight loss advice remains constant, to follow a low-fat diet. However, a study recently published in the International Journal of Obesity questions that strategy. Scientists were interested in learning whether people who followed a low-calorie diet with a higher fat intake than typically recommended would have better weight loss success than those on a low-fat diet of the same calorie level.

Is increasing the fat the answer?

In this study, 101 healthy men and women were randomly assigned to 1 of 2 groups. The difference between the groups was the amount of fat they were encouraged to eat. The low-fat group consumed meals that provided about 20% of calories from fat whereas the moderate fat group had a more liberal allotment of 35%. Participants were encouraged to follow a "Mediterranean style diet," emphasizing plant-based foods and fats. Both groups followed the same low calorie level (1200 for women and 1500 for men). Registered dietitians conducted weekly group education classes for the entire 18 months of the study.

Overall the participation rates in this study were low. At 6 months, only 45% of the low-fat group and 64% of the moderate fat group were still attending. These numbers dropped to 27% and 58% respectively at the end of the first year.

At the 6-month mark, the average weight loss in both groups was about 11 pounds (5 kg). After 18 months, the group following the moderate fat diet had regained some weight, but was still an average of 9 lbs (4.1 kg) lighter. Those in the low-fat group, however, were an average of 6 lbs (2.9 kg) heavier than they were at the start of the study.

Looking for ways to stick to a diet

Over 23% of American adults are obese, making obesity a primary health concern. Excess weight can contribute to the development of chronic diseases such as heart disease, cancer and diabetes. The results of this study are very typical. People can lose weight initially on low-calorie, low-fat diets but have great difficulty keeping the weight off. One possible reason is that low-fat diets are less flavorful and appealing, making long-term compliance difficult.

This study attempts to find a way to improve the palatability of weight reduction diets by increasing the amount of fat. The rationale is that the higher fat content, plus the fiber-rich fruits, vegetables, and whole grain foods emphasized in a "Mediterranean style" diet may increase satiety, so dieters feel fuller on less food.

Advice for today

The best way to lose weight is to increase physical activity and to follow a low-calorie diet. When choosing fats, select unsaturated fats such as olive oil and canola oil and remember to use them in limited amounts. Current recommendations limit fat intake to 30% of total calories to reduce the risk of heart disease. This small study examining whether a more liberal fat intake can increase diet compliance provides interesting results that warrant further investigation.

Source

A randomized controlled trial of a moderate low-fat, low-energy diet compared with a low-fat, low-energy diet for weight loss in overweight adults
K. McManus, L. Antinoro, F. Sacks, Inter J Obesity, 2001, vol. 25, pp. 1503--1511

Links

• Mediterranean Diet, Traditional Risk Factors, and the Rate of Cardiovascular Complications after Myocardial Infarction: Final Report of the Lyon Diet Heart Study
• How to be a good (weight) loser - Part 3: trouble shooting tough spots
• Overweight reduces lifespan (really)
• Modest Weight Loss Helps Control High Blood Pressure
• To quickly access additional accurate information on this and other nutrition-related topics, visit Tufts University's Nutrition Navigator