Healthy eating habits can't begin early enough. For kids, the American Heart Association recommends a diet high in whole grains, vegetables and fruits but with limited juice and low in saturated fat, trans fat, salt and added sugars. Infants need extra fat and calories for development, but as they grow, they should begin to eat a leaner diet. "Until age 2, kids should be taking whole milk," says Hagan, "but beginning at age 2, they should be on a lower-fat milk. We want them to develop a taste for low fat."