While most diets focus on foods you shouldn't eat, those that emphasize adding low-calorie foods, like fruits and vegetables, can promote healthy weight loss, new research shows.
Some weight-loss plans shun carbohydrates while others ban fat, but in the new study, researchers found that overweight adults who were instructed to focus on lower-calorie foods lost more weight than their peers who were simply told to cut their overall calories. The key, according to the study authors, is that foods such as fruits and vegetables have low "energy density." Because they have a high water content, they are heavy by weight but low in calories; while such foods do not add many calories to the diet, they are still filling.
The study included generally healthy men and women with borderline-high blood pressure who were randomly assigned to one of three groups, to look at the effect on blood pressure. Of these 658 men and women, those who made the greatest reductions in the energy or calorie density of their diets lost an average of 13 pounds over 6 months. Those who made the smallest reduction in energy lost a meagre 5 pounds over the same period.
The findings of the study, carried out by Jenny H Ledikwe and her colleagues, of Pennsylvania State University, was published in the American Journal of Clinical Nutrition.
The difference was that one group was told to follow the "DASH" diet, which emphasized getting 9 to 12 daily servings of fruits and vegetables, and 2 to 3 servings of low-fat dairy products. The other groups were told to reduce their calorie intake, but were not given goals for fruit, vegetable and dairy intake. Overall, Ledikwe's team found, the DASH group cut down the most on calorie density,despite started eating more food by weight -- a consequence of getting more fruits and vegetables. The group was also able to increase intake of fiber, vitamins and minerals.
Diets that emphasize low-calorie foods may be easier to stick to than diets that focus on foods to avoid, the investigators point out, as well as more healthful.
"Whereas a decrease in body weight is a primary goal of a weight-loss diet," Ledikwe and her colleagues write, "consideration of nutritional quality is equally important."