Research shows moderately reducing carbohydrates may help weight loss

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A diet with a slight reduction from the American norm of calories from carbohydrates may help in weight loss, say UAB researchers.

A diet with a slight reduction from the American norm of calories from carbohydrates may help in weight loss, say UAB researchers.
In findings presented June 11 at the annual meeting of the Endocrine Society in Washington, D.C., the researchers compared subjects who ate a breakfast with a standard amount of calories from carbohydrates against those whose meal had a moderate reduction in calories from carbohydrates. The moderate carb group had less fluctuation in glucose levels and greater feelings of fullness in the hours following the meal.

Glucose, a sugar that provides energy to the body, reacts to insulin levels. Diets high in carbohydrates, particularly simple carbohydrates, cause a spike in insulin levels, which in turn drives glucose levels down. Low glucose levels cause the body to send hunger signals.

"Subjects on the moderate carbohydrate diet had a smaller increase in insulin and thus a more stable glucose level," said Barbara Gower, Ph.D., professor in the Department of Nutrition Sciences. "They reported that they felt fuller for a longer period of time following the meal than did those with a diet more in line with what most Americans consume. Ultimately, this may help with weight loss because people may be less likely to overeat due to hunger pangs."

Gower and colleague Paula Chandler-Laney, Ph.D., a post-doctoral fellow at UAB, reported on 30 patients enrolled in the Diet QuEST (Quality and Education to Stay Trim) study. According to 2005 Dietary Guidelines for Americans published by the U.S. Departments of Agriculture and Health and Human Services, the recommended range of calories from carbohydrate is between 45 to 65 percent. Fourteen patients in the QuEST study ate a standard diet containing 55 percent calories from carbohydrates, and 16 consumed a meal containing 43 percent calories from carbohydrates.

The study subjects, all slightly overweight but otherwise healthy adults, acclimated to their assigned diet for four weeks. Data were collected following a breakfast test meal in which participants consumed a breakfast consistent with either their standard carb or moderate carb diet. The meals contained common breakfast foods such as frozen waffles, oatmeal, fruit and fruit juice, bread, peanut butter and jelly, milk, eggs, cheese, breakfast meats and oatmeal.

"When looking at the menus for the entire day, it's hard to tell which diet is the standard one and which is the moderate carb diet," said Gower. "One difference is that the moderate diet has more complex carbohydrates rather than simple carbs."

Gower says simple carbohydrates, found in products such as soft drinks, processed foods or white bread, cause higher, more dramatic insulin spikes and the corresponding larger glucose drop. Complex carbs, such as non-processed foods, beans, oatmeal or whole grains, minimize the increase in insulin and keep glucose at more stable levels.

The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), one of the National Institutes of Health (NIH).