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 stated. "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.
