Noninsulin-dependent diabetes mellitus is a major health problem, highly correlated with obesity and, therefore, overeating. Diet continues as the cornerstone of therapy, with oral hypoglycemic agents or insulin added, if needed, to maintain normal blood glucose values. The diet prescription should be implemented in stages, with caloric restriction the first priority, as weight loss itself diminishes hyperglycemia to or toward normal. Combinations of foods and even different processing or cooking of the same food may produce different glucose responses. These factors minimize the role of the glycemic index in overall diabetes management. Foods with high soluble fiber content may diminish glucose elevations after meals; however, high-fiber foods appear to be less important for the obese diabetic person than adhering to a calorie-restricted diet and achieving weight loss. Attempts should be made to alter life-style within an acceptable degree for any given patient to encourage weight reduction. For example, although exercise may have a small but transient direct effect in lowering blood glucose and insulin resistance, it can be considered an adjunct to decreased calorie diets for weight reduction. Finally, it appears prudent to prevent or reverse obesity, especially in individuals with a family history of diabetes, in the hope that the onset of diabetes may be prevented or postponed.