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Diet and exercise programs may help people with type 2 diabetes lose weight

Terranova CO, Brakenridge CL, Lawler SP et al. Effectiveness of lifestyle-based weight loss interventions for adults with type 2 diabetes: A systematic review and meta-analysis. Diabetes, Obesity and Metabolism. 2015; 17(4), 371-378.

Review question

Do diet and exercise programs help adults with type 2 diabetes lose weight?

Background

Type 2 diabetes and obesity are becoming more common. Obesity increases the risk of developing type 2 diabetes, makes it more difficult to manage the disease, and increases other health risks, such as high blood pressure, heart disease and even death. For overweight or obese people with diabetes, a 5-10% weight loss is recommended to lower risk of health complications and need for medications. Many weight loss approaches focus on lifestyle changes, such as improving diet and exercise levels but more research is needed to understand how well these approaches work for people with type 2 diabetes.

How the review was done

This is a review of 10 randomized controlled trials measuring the impacts of diet and exercise programs on changes in weight (in kg) and blood sugar control (HbA1c) for people with diabetes. The different programs ranged in length from 16 weeks to 9 years. Nine were face-to-face programs and one was conducted by phone. The number of participants ranged from 27 people in the smallest study to 5145 in the largest study with an average age of 47-60 years.

What the researchers found

The included studies varied in quality. Compared to usual care, lifestyle-based weight loss programs were more effective for weight loss (~5.4%), than blood sugar control.  Blood sugar changes were most significant in groups which had the greatest weight loss (>20% of body weight). The four most successful programs included: a) a short-term very low calorie diet; b) laparoscopic band surgery; c) a participant fee, which may have increased motivation; d) meal replacements. These approaches may not be recommended or sustainable for all people with type 2 diabetes. Only 1 study followed-up with participants 12 months after the program. They found that many participants had regained weight and their blood sugar levels had returned to pre-program levels. However, the follow up was poorly reported and the authors recommend these results be interpreted with caution. Future studies should report on a long-term follow up of study participants and the cost of such programs.

Conclusion

Lifestyle-based weight loss programs (focused on diet and exercise changes) may help people with type 2 diabetes lose a modest amount of weight. More studies are needed to make these types of programs more effective.