Losing weight when obese can prevent or cure diabetes, whatever the initial BMI, study suggests

Addressing diabetes is a major priority for health providers worldwide given the vast global prevalence (approx. six to seven per cent of the world's population; around 285 million people) and its severe complications including amputations and heart disease. Surgery for weight loss has an unexpectedly rapid and substantial therapeutic effect on diabetes rates. Understanding why weight loss has such a dramatic effect on diabetes is the focus of this study by Associate Professor Markku Peltonen from the National Institute for Health and Welfare, Finland and colleagues from the University of Gothenburg, Sweden.

The researchers enrolled the 2010 patients from the Swedish Obese Subjects study who had received bariatric surgery and 2037 obese controls receiving conventional (non-surgical) obesity treatment. They were assessed for BMI and diabetes at baseline (before surgery in the surgical group), and at two and 10 year follow-up.

Among patients with BMI<35, 35-40 and 40-45 who did not lose weight after two years, type 2 diabetes incidence rates were 6.5%, 7.7% and 9.3% respectively. Among those with initial BMI 35-40, 40-45 and ≥45 who lost at least five BMI units after two years, type 2 diabetes incidence rates were 2.4%, 2.0% and 3.4% respectively, clearly showing that lower rates of diabetes can be found among obese patients who have lost five BMI units through any means. Further analysis showed that the rate of patients cured of diabetes after losing five BMI units was independent of the starting BMI at all BMI levels measured. This trend was also observed after 10 years post surgery.

The findings suggest that losing five BMI units, the equivalent of approx. 16kg for a 180cm tall 35 year old man weighing 130kg (BMI 40), can make a real difference to your health by reducing your likelihood of having type 2 diabetes. Furthermore, it suggests that this is true for all patients, as even those who were severely obese showed dramatic improvements.

Associate Professor Markku Peltonen, Director of Department at the National Institute for Health and Welfare, Finland, said:

"Our findings show that, whatever your starting weight, losing five BMI units can dramatically reduce your risk of having type 2 diabetes after two and ten years.

"Dropping five BMI units is no mean feat, as the human body is not very good at losing weight. But patients of any weight should take encouragement that by doing so they can really improve their chances of a healthy future."