Foods with a low-glycemic index, which are digested relatively slowly and cause smaller increases in blood sugar, may protect the heart and blood vessels better than low-fat fare, according to the findings of a small study. Researchers in Boston found that when obese people consumed as many carbohydrates with a low-glycemic index as they wanted, they lost just as much weight in 12 months as people who stuck with a conventional, calorie-restricted low-fat diet. Carbohydrates with a low-glycemic index include foods such as nonstarchy vegetables, fruit, legumes, nuts and diary products, according to the report in the American Journal of Clinical Nutrition.