The Waianae Diet Program is a community-based intervention strategy designed to be culturally appropriate by using a pre-Western-contact Hawaiian diet to reduce chronic-disease risk factors in Native Hawaiians. This paper describes a trial of the traditional Hawaiian diet fed ad libitum to Native Hawaiians with multiple risk factors for cardiovascular disease to assess its effect on obesity and cardiovascular risk factors. Twenty Native Hawaiians were placed on a pre-Western-contact Hawaiian diet for 21 d. The diet was low in fat (7%), high in complex carbohydrates (78%), and moderate in protein (15%). Participants were encouraged to eat to satiety. Average energy intake decreased from 10.86 MJ (2594 kcal)/d to 6.57 MJ (1569 kcal)/d. Average weight loss was 7.8 kg (P less than 0.0001) and average serum cholesterol decreased 0.81 mmol/L (P less than 0.001) from 5.76 to 4.95 mmol/L. Blood pressure decreased an average of 11.5 mm Hg systolic (P less than 0.001) and 8.9 mm Hg diastolic (P less than 0.001).