Fruit and fiber the key to weight management: study

NEW YORK (Reuters Health) – By studying the diets of 52
normal-weight adults and 52 overweight or obese adults,
researchers found that normal-weight adults ate more fiber and
fruit each day than their overweight and obese counterparts.

“These findings suggest that the composition of a diet,
especially low dietary fiber and fruit intake, play a role in
the (development) of obesity,” concludes the study team in the
Journal of the American Dietetic Association.

For all study subjects, Dr. Jaimie N. Davis of the
University of Southern California in Los Angeles and colleagues
determined the dietary amount of 60 food items using a food
frequency questionnaire, assessed physical activity levels and
determined percent body fat. All of the subjects were about the
same age and height.

Davis’ group found marked differences in the dietary habits
of the two groups. The overweight and obese subjects consumed
more total fat, saturated fat and cholesterol, and less
carbohydrate, specifically dietary fiber and complex
carbohydrate, than normal weight subjects.

The differences in diet composition “may have played a
vital role in promoting or preventing obesity,” they write.

Normal-weight adults consumed an average of 33 percent more
dietary fiber and 43 percent more complex carbohydrates daily
than their overweight and obese counterparts. Dietary fiber and
complex carbohydrate intake were inversely related to body
weight and “most strongly” to percent body fat.

Compared with normal-weight subjects, overweight and obese
subjects consumed about one less fruit serving daily, which may
partly explain their lower fiber and carbohydrate intake.

There are several mechanisms by which dietary fiber may
reduce the risk of weight gain or obesity. Dietary fiber, for
example, slows digestion, prolonging that “full” feeling and
foods high in fiber are usually low in fat and calories.

“The public is still attracted to popular weight-loss
strategies that emphasize decreasing carbohydrate and
increasing fat and protein,” the study team notes in their
report.

“Although there is evidence that high-protein,
low-carbohydrate diets produce substantial weight loss in the
short-term, to date there are no long-term studies that examine
the effects of these regimens.”

While there is no magic formula for weight loss, in the
current study, “dietary fiber, complex carbohydrates and fruit
were associated with lower body fat stores in adults,” Davis
told Reuters Health. “These results suggest that increasing
dietary fiber, complex carbohydrates and fruit in an
individual’s diet should be an important part of dietary
interventions,” the researcher concluded.

SOURCE: Journal of the American Dietetic Association, June
2006.