Calories Count More Than Food Type
Keys to Weight Loss: Calories, Calories, Calories
April 9, 2007 -- If you're trying to lose weight, calories count more than
the types of food in your diet, a U.S. Department of Agriculture-Tufts
University study shows.
The study shows that after a year, overweight people on a low-carb
low-glycemic-index diet lost just as much weight -- 8% of their original weight
-- as people on a reduced-fat, high-glycemic-index diet.
"The present results suggest that a broad range of healthy diets can
successfully promote weight loss," conclude Sai Krupa Das, PhD, and Susan
B. Roberts, PhD, of the USDA's Human Nutrition Center on Aging at Tufts, and
"A wide variability in the balance of different dietary macronutrients
has little effect on mean long-term weight loss during calorie
restriction," Das, Roberts, and colleagues suggest.
The study, funded by the National Institute on Aging, was small but highly
sophisticated. The yearlong study enrolled 34 healthy, overweight men and
All study participants went on diets designed to cut their calorie counts by
Half went on a low-glycemic-load diet, a form of low-carb diet that avoids
sugary, starchy foods. It's sometimes called a "slow-carb" diet. They
got 40% of their calories from carbs, 30% from fats, and 30% from protein.
The other study participants, whose high-glycemic-index diet was matched for
taste, attractiveness of appearance, and calorie count, got 60% of their
calories from carbs, 20% from fats, and 20% from protein.
Study participants attended weekly behavioral support groups and had regular
individual meetings with a dietitian.
Since people in diet studies rarely eat the foods they are supposed to eat,
Das and colleagues provided their study participants with foods for the first
six months of the study. After giving them shopping and cooking classes,
subjects were allowed to buy and prepare their own foods for the second six
months of the study.
Energy-intake measures and food diaries showed that people in both groups
cheated. But at the end of a year, both groups lost the same amount of weight
and the same amount of body fat.
Low-carb diet advocates say people are more likely to stay on these diets
because they provide more of the foods people like to eat. The study offers
some support for this. During the first three months of the study, when
subjects were most compliant with their diets, those in the high-glycemic-index
group were less satisfied and had more desire for nondiet foods.
Yet by the end of the year, neither group ate more or less than the other.
That may be because the researchers made an effort to ensure that the
high-glycemic-index foods were as tasty and attractive as the
"However, we did detect a greater tendency for weight and body-fat
regain among low-glycemic-diet participants," Das said in a news release.
"This finding suggests that reduced caloric intake may be harder to sustain
on low-glycemic diets over time."
The findings appear in the April issue of the American Journal of