"Glycemic load" of diet has no effect on weight loss

NEW YORK (Reuters Health) - When it comes to losing weight, the number of
calories you eat, rather than the type of carbohydrates, may be what matters
most, according to a new study.

The findings, published in the American Journal of Clinical Nutrition,
suggest that diets low in "glycemic load" are no better at taking the pounds
off than more traditional -- and more carbohydrate-friendly -- approaches to
calorie-cutting.

The concept of glycemic load is based on the fact that different
carbohydrates have different effects on blood sugar. White bread and
potatoes, for example, have a high glycemic index, which means they tend to
cause a rapid surge in blood sugar. Other carbs, such as high-fiber cereals
or beans, create a more gradual change and are considered to have a low
glycemic index.

The measurement of glycemic load takes things a step further by considering
not only an individual food's glycemic index, but its total number of
carbohydrates. A sweet juicy piece of fruit might have a high glycemic
index, but is low in calories and grams of carbohydrate. Therefore, it can
fit into a diet low in glycemic load.

However, the effort of figuring out what's an allowable carb might not be
worth it, if the new study is any indication.

Principal investigator Dr. Susan B. Roberts, of Tufts University, Boston,
and colleagues found that a reduced-calorie diet, whether glycemic load was
high or low, was effective in helping 34 overweight adults shed pounds over
one year.

Study participants who followed a low-glycemic-load diet ended up losing
roughly 8 percent of their initial weight, as did those who followed a
high-glycemic-load diet.

"The bottom line is that in this study we don't see one single way to eat
that is better for weight loss on average," Roberts told Reuters Health. Of
course, that doesn't mean "anything goes" as long as you're cutting
calories."

A super-sized serving of French fries won't do any dieter any good, she
noted.

Both diets her team used in the study were carefully controlled. For the
first 6 months, participants were provided with all the food they needed,
and both diets were designed to cut their calories by 30 percent while
providing the recommended amount of fiber, limiting fat and encouraging
healthy foods like fruits and vegetables.

The comparable outcomes suggest that, among healthy diets, no single one
stands out as better, according to Roberts. So the focus should be on
calories, rather than specific foods to avoid or include.

"Focusing on calories is something we need more of, especially when portion
sizes are so absurd," Roberts said, referring to the portions served at so
many U.S. restaurants.

This doesn't mean, however, that there's no place for diets that focus on
glycemic load, according to the researcher. Some studies, for example, have
found that low-glycemic index foods might help control blood sugar in people
with type 2 diabetes.

And in their own research, Roberts said she and her colleagues have found
that low-glycemic index diets do seem more effective for overweight people
who naturally secrete high levels of the hormone insulin, which regulates
blood sugar.

SOURCE: American Journal of Clinical Nutrition, April 2007.