Look AHEAD (Action for Health in Diabetes): design and methods for a clinical trial of weight loss for the prevention of cardiovascular disease in type 2 diabetes.

Look AHEAD is examining, in overweight volunteers with type 2 diabetes, the long-term effects of an intensive lifestyle intervention program designed to achieve and maintain weight loss by decreased caloric intake and increased physical activity. This program will be compared to a control condition involving a program of diabetes support and education.

The primary hypothesis is that the incidence rate of the first post-randomization occurrence of a composite outcome, which includes

cardiovascular death (including fatal myocardial infarction and stroke), non-fatal myocardial infarction, hospitalized angina, and non-fatal stroke,

over a planned follow-up period of up to 13.5 years will be reduced among participants assigned to the Lifestyle Intervention compared to those assigned to the control condition, Diabetes Support and Education.

Look AHEAD will also test for reductions in the incidence of three secondary composite outcomes and examine the effect of the intervention on cardiovascular disease risk factors, diabetes control and complications, general health, and quality of life, and psychological outcomes. The cost and cost-effectiveness of the Lifestyle Intervention relative to Diabetes Support and Education will be assessed.

The Look AHEAD intensive lifestyle intervention ended September, 2012. Participants continue to be followed to determine the long-term effects of the intervention on health outcomes.