High levels of the hormone insulin are associated with risk for heart disease and diabetes, and may make it hard to lose weight. The types of food eaten may affect insulin levels. The purpose of this study is to determine if manipulation of dietary carbohydrate content improves insulin sensitivity (Si), augments weight loss, and promotes weight loss maintenance in healthy adults.

Inclusion Criteria:

Overweight, age 21-50 years,Women must be premenopausal, Normal glucose tolerance, weight stable for at least 6 months with a weight change no greater than 5 lbs.

Exclusion Criteria:

Exclusion criteria were type 1 or type 2 diabetes, polycystic ovarian disease, BMI <26.5 or weight >300 pounds, weight change >5 pounds in last 6 months, regular exercise >2 hours per week, pregnancy, currently breastfeeding, cholesterol medications, any disorders of glucose or lipid metabolism, use of medication that could affect body composition or glucose metabolism (including oral contraceptives and blood pressure medications), current use of tobacco, use of illegal drugs in last 6 months, history of hypoglycemic episodes, major food allergies or food dislikes, women with inconsistent or absence of monthly menstrual cycles, and a medical history that counter-indicated inclusion in the study.