Carbohydrates Improve Diet Quality

Many fad diets are based on restricting carbohydrates while increasing protein and fat. A new survey from the USDA shows that diets high in carbohydrates are lower in calories and, generally, higher in nutrients. Also, adults eating high-carbohydrate diets are more likely to be in the normal weight range.

About 55 percent of adults in the U.S. are either overweight or obese and this rate has increased greatly over the last 20 years.

The U.S. Department of Agriculture's Continuing Survey of Food Intakes by Individuals 1994-1996 collected diet data on 10,014 free-living adults across the country. The sample was divided into four levels of carbohydrate intake -- less than 30 percent, 30-45 percent, more than 45-55 percent, and more than 55 percent.

Those eating the highest carbohydrate consumed up to 300 Calories less per day while eating the same amount of food. This was primarily due to increased dietary fiber and water content of the high-carbohydrate foods per 1,000 Calories of energy intake. Those choosing diets with the most carbohydrate had the lowest average body-mass index. They also consumed more essential nutrients such as vitamin A, carotene, vitamin C, folate, calcium, magnesium, and iron. Nutrients consumed in lower amounts by this group were fat, saturated fat, cholesterol, sodium, zinc, and vitamin B12.

Dr. Shanthy Bowman, lead author of the study and a scientist with the USDA, said that "adults who obtained more than 55 percent of their energy from carbohydrate had an energy-restrictive, yet nutritious diet, no matter what their food selection strategies." Adults in the high-carbohydrate group did not avoid milk, meat, poultry, and fish products but chose low fat items from these food groups.

This study also identified 10-14 percent of all calories coming from beverages, both alcoholic and nonalcoholic. "Reducing intake of non-nutritious beverages that are high in calories is another strategy identified by this study that could help people control weight gain without compromising the quality of the diet," according to Dr. Bowman.

The findings appeared in the June, 2002 issue of the Journal of the American College of Nutrition.