Intensive lifestyle interventions designed to achieve and maintain weight loss over the long term lead to improvements in a variety of cardiovascular risk factors, including weight, fitness level, blood glucose control, blood pressure, and HDL cholesterol, according to four-year results from the Action for Health Diabetes (Look AHEAD) study. This trial, sponsored by the National Institutes of Health, is designed to study the long-term effects of weight loss resulting from reduced caloric intake and increased physical activity in people with diabetes, who are two to four times more likely to develop cardiovascular disease than those without diabetes.
The researchers randomly assigned 5,145 overweight or obese people with Type 2 diabetes to one of two groups: Those in the intensive lifestyle intervention group were encouraged to reduce their caloric intake and exercise up to three hours weekly, resulting in a roughly 10% average loss of body weight. Participants assigned to this group also had weekly counseling sessions, designed to reinforce the lifestyle changes, for the first six months of the study, and monthly counseling sessions thereafter. People in the diabetes support and education study group, which served as the control, met three to four times per year, but were not required to lose weight or exercise.
In the first year, participants in the intensive lifestyle intervention group lost significantly more weight, and they achieved a higher level of fitness and maintained greater weight loss over the course of the four-year study period. Levels of HDL (“good”) cholesterol also increased more among those in the intensive intervention group, while HbA1c levels (a measure of blood glucose control over the previous 2–3 months) and systolic blood pressure (the top number, measured when the heart is contracting) were reduced to a greater degree in this group. Additionally, more people in the intensive intervention group were able to stop taking blood pressure and diabetes medicines than those in the control group.
The only risk factor that was not significantly different between the two groups at the end of four years was the level of LDL, or “bad,” cholesterol, which the investigators attribute to a greater increase in the use of cholesterol-lowering statins among those in the control group.
According to lead study author Rena Wing, PhD, “If you look at averages across the four years, we see that a lifestyle intervention produced significantly greater improvements across all four years for all of the cardiovascular-disease risk factors, except LDL cholesterol… We’re hoping the intensive intervention will reduce cardiovascular morbidity and mortality. We’re hoping people will live longer.”