An hour every day

The Institute of Medicine issued new guidelines this fall that double the daily recommendation for exercise. In the past, the institute, part of the National Academies of Science, has focused more on nutritional requirements and less on physical activity.

The recommendation calls for one hour a day of "moderate physical activity" such as jogging, swimming or fast walking. That is double the old recommendation.

"It's important for people to realize they can't have their cake and eat it too—unless they run around the block with it," said Alice H. Lichtenstein, professor of nutrition and director of the Cardiovascular Nutrition Research Program at the Jean Mayer USDA Human Nutrition Research Center on Aging, who served on the Institute of Medicine panel that released the recommendations.

In addition, the guidelines now call for consumers to get 45 to 65 percent of calories from carbohydrates, 20 to 35 percent from fat and 10 to 35 percent from protein. Lichtenstein commented on the panel establishing a range of nutrients for the first time: "By setting ranges, there has been an acknowledgment that we as humans do eat relatively higher and lower percentages based on our individual needs, desires and cultures."