Staying away from simple
carbohydrates and eating plenty of fiber
may help women avoid packing on pounds as
they get older, a study by Danish researchers
suggests.
Dr. Helle Hare-Bruun
of Copenhagen University Hospital and colleagues
found that normal-weight women who ate a diet
with a relatively high glycemic index gained
more weight, more fat, and more padding around
the middle over a six-year period than women
who ate a low glycemic index diet.
But larger, longer-term studies are needed
to show how a low glycemic index diet affects
weight regulation, Dr. Mark A. Pereira of
the University of Minnesota in Minneapolis
writes in an accompanying editorial.
Glycemic index is a measure of how quickly
a food causes blood sugar, or "glucose," to
rise. Generally, foods with refined sugars
and simple starches, like candy and white
bread, have a high glycemic index, while those
with more complex carbohydrates and greater
fiber content, such as vegetables and whole
grains, have a low glycemic index.
Theoretically, a high glycemic index diet
could make a person feel hungry faster and
eat too much as a result, Hare-Bruun and colleagues
note. But studies of the effects of dietary
glycemic index on weight loss have had mixed
results, they report in the American Journal
of Clinical Nutrition.
To see how dietary glycemic index might affect
weight over time, the researchers evaluated
376 normal-weight men and women ages 35 to
65 years and followed-up with them six years
later.
As mentioned, a high glycemic index diet
correlated with greater waist circumference,
body weight, and percentage of body fat in
women, the researchers found, and the effect
was strongest among inactive women. But glycemic
index had none of these effects on men. The
researchers suggest that gender somehow affects
the influence of glycemic index on weight
gain.
"A low glycemic index diet may protect against
increases in body weight and general and abdominal
obesity in women -- especially in those who
are sedentary -- which suggests that physical
activity may offer protection against diet-induced
weight gain and obesity," they conclude.
But given the relatively small size of the
current study and the difficulty of accurately
evaluating diet from self-reports, Pereira
writes in his editorial, much larger, long-term
trials are needed to answer the question of
how dietary glycemic index affects body weight.
SOURCE: American Journal of Clinical Nutrition,
October 1, 2006.
