Less Carbohydrates Keeps People Full Longer

Study Says Less Carbohydrates 

"There has been great public interest in low-carbohydrate diets for weight loss, but they are difficult to maintain, in part because of the drastic reduction in carbohydrates," said coauthor Barbara Gower, PhD, a professor in the Department of Nutrition Sciences, University of Alabama at Birmingham.

In the study researchers investigated whether a modest reduction in dietary carbohydrates, or "carbs," would improve feelings of fullness better than a carbohydrate level comparable to that of the typical U.S. diet.

In a standard American diet, according to the researchers, 55 percent of daily calories consumed come from carbohydrates: sugars, starches andfiber.

The "moderate-carb diet" diet contained 43 percent of calories from carbohydrates and 39 percent of the calories from fat. Protein intake was 18 percent for both diets. The researchers matched the protein intake of both diets studied because protein may influence both satiety ("fullness") and insulin secretion.

The control diet used in their study contained 55 percent of daily calories from carbohydrates, and 27 percent of calories from fat.

The researchers assigned the moderate-carb diet to 16 adults and the standard diet to 14 adults for a month. Subjects received enough calories to maintain their weight at what it was before the study. During the study they were weighed each weekday, and if a participant gained or lost weight, the amount of food was modified individually so weight could stay the same. After the subjects adjusted to their diet for 4 weeks, they ate a test meal, a breakfast that was specific to their diet.

When carbohydrates are eaten and digested, carbohydrates change into sugar. Before and after the meal, the researchers measured the subjects' levels of insulin and circulating glucose (nonfasting blood sugar) and asked them to rate their hunger or fullness. They evaluated insulin response to a meal and blood sugar levels, because lower insulin and stable blood sugar levels may contribute to increased feelings of fullness, Gower explained.

The research showed that a modest reduction in dietary carbohydrates was sufficient to lower insulin and stabilize blood sugar after a meal, and increase satiety (fullness). Ratings of fullness were higher in the group on the moderate- carbohydrates diet before eating breakfast and stayed higher for a longer time after the meal, compared with those eating the standard diet (e.g., 55 percent of daily calories consumed come from carbohydrates).

"Over the long run a sustained modest reduction in carbohydrate intake may help to reduce energy consumption and facilitate weight loss," Gower said.