New NIH Study: Diet and Exercise for Type 2 Diabetes, Heart Disease Not Effective?
People with type 2 diabetes, all 24 million of them in the United States alone, have undoubtedly heard the chapter and verse – change your diet, lose weight, and exercise more – if you want to reduce the risk of heart disease. It may be more like two out of those three. A long-term (11 years) clinical trial involving 5,145 people in 16 centers around the United States, studied the effects of an intensive diet and exercise program for overweight or obese individuals with type 2 diabetes. The goal was to see if this lifestyle intervention reduced the occurrence of heart disease events. It did not, and the researchers stopped this part of the study early.
This result seems to fly in the face of decades of ‘good advice.’ The Look AHEAD (Action for Health in Diabetes) study tested an intensive lifestyle intervention – diet and exercise – to achieve weight loss. They split the participants among those receiving the intervention and those in a general program of diabetes support and education.
All the participants were people with type 2 diabetes and either overweight or obese – people at risk for high rates of heart disease, stroke and cardiovascular related deaths. The ages of people in the trials were from 45 to 75 years when they enrolled. They were of mixed gender (60% women) and race (37% from racial and ethnic minorities). Both trial groups received their normal medical care from their own providers. Researchers tracked their record within the program and their incidence of cardiovascular events.
In terms of weight loss, the trials were successful. Participants in the intervention group lost an average of more than 8% of their body weight in the first year. They maintained an average weight loss of about 5% over a period of at least 4 years. The participants in the general support group lost about 1% of initial weight for both 1 year and the 4 year period.
The comparison of the two groups forced the conclusion – there was no significant difference between them in the occurrence of cardiovascular events. The results were definitive enough for the governing board of the trials to call for ending the high intensity intervention part of the study.
As of now, the final results are under review and there will be analysis of the lack of correlations between weight loss and cardiovascular disease for future publication.
On the other hand, while the results are surprising, there is more to the context. For one thing, both trial groups had a lower incidence of cardiovascular disease compared to people in previous studies of type 2 diabetes. Although the intense diet-exercise intervention did not reduce cardiovascular events, there were other benefits. This included decreasing sleep apnea, reducing the need for diabetes medication, increased physical mobility, and general improvement in quality of life.
The Look AHEAD program is the first, largest and longest running trial of an intensive diet-exercise intervention program in the U.S. and while the intervention program of the study stopped, researchers will continue to monitor the health records of the participants who volunteer to continue.
According to Dr. Griffin Rodgers, director of the National Institutes of Health, National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK), and principle sponsor the study, “Look AHEAD provides important, definitive information about the long-term health effects of weight loss in people with type 2 diabetes. Beyond cardiovascular disease, this study and others have shown many other health benefits of weight loss through improved diet and increased physical activity. For example, for overweight and obese adults at high risk for diabetes, modest weight loss has been shown to prevent or delay developing type 2 diabetes.” In conclusion, a healthy, balanced diet and exercise program can help improve your health and decrease the risk of developing type 2 diabetes and a host of other medical problems.