NAS report good news for cereals; sets fiber levels

by Emily Wilson
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WASHINGTON D.C., U.S. — Adults should get 45% to 65% of their calories from carbohydrates, says the newest report on recommendations for healthy eating from the National Academies of Science Institute of Medicine.

In order to meet the body’s daily energy and nutritional needs while minimizing risk for chronic disease, fat should supply 20% to 35% of calories consumed, while 10% to 35% should come from protein, the report says. Earlier guidelines called for diets with 50% or more of carbohydrate and 30% or less of fat; protein intake recommendations are the same.

The new acceptable ranges for children are similar to those for adults, except that infants and younger children need a slightly higher proportion of fat — 25% to 40% of their caloric intake, said the panel that wrote the report."We established ranges for fat, carbohydrates, and protein because they must be considered together," said panel chair Joanne Lupton, professor of nutrition, Texas A&M University, College Station, Texas. "Studies show that when people eat very low levels of fat combined with very high levels of carbohydrates, high-density lipoprotein concentration, or ‘good’ cholesterol, decreases. Conversely, high-fat diets can lead to obesity and its complications. We believe these ranges will help people make healthy and more realistic choices based on their own food preferences." The report stresses the importance of balancing diet with exercise, recommending total calories to be consumed by individuals of given heights, weights, and genders for each of four different levels of physical activity.The report contains the first recommended intake levels for fiber from the Food and Nutrition Board. The fiber recommendations are based on studies that show an increased risk for heart disease when diets low in fiber are consumed. Although there is evidence to suggest that fiber in the diet may also help to prevent colon cancer and promote weight control, the data are inconclusive at this point.

The recommended daily intake for total fiber for adults 50 years and younger is set at 38 grams for men and 25 grams for women, while for men and women over 50 it is 30 and 21 grams per day, respectively. The report defines "total fiber" as the combination of "dietary" and "functional" fiber. Dietary fiber is the edible, indigestible component of carbohydrates and lignin naturally found in plant food. Some foods with dietary fiber include cereal bran, flaked corn cereal, sweet potatoes, legumes and onions. Functional fiber refers to those fiber sources that have been shown to have similar health benefits to dietary fiber, but are isolated or extracted from natural sources or are synthetic. The definition of functional fiber aims to exclude fiber-like products, whether extracted or synthesized, that cannot be shown to have proven health benefits. It is hoped that regulatory bodies in both the United States and Canada will work toward adopting these definitions.