Why Some Obese People Do Not Get Diabetes
Most people who have diabetes are overweight or obese, and so it is common to believe that obese or even morbidly obese individuals would likely have diabetes. Yet this assumption often is not true, and now a group of researchers believe they know why.
It is estimated that about 85 percent of people who develop type 2 diabetes are obese. Obesity is defined as having a body mass index (BMI) of 30 or greater, with BMI being a measure of a person’s body fat based on height and weight. (You can determine your BMI using an online calculator.)
The healthy obese and diabetes
Researchers in Spain and Cambridge studied volunteers who had a BMI of about 56 and evaluated their inflammatory and insulin signalling pathways. They discovered that the “healthy” obese individuals did not have an inflammatory response found in unhealthy, insulin-resistant obese adults. This inflammatory response impacts insulin resistance through expression of substances called cytokines interleukin 1-beta and interleukin 6.
According to the Weight-Control Information Network, which is associated with the National Institute of Diabetes and Digestive and Kidney Diseases, experts do not know why people who are overweight are more likely to develop diabetes. One theory is that being overweight causes cells to become resistant to insulin. Insulin resistance means blood sugar cannot be taken up by the cells, which results in high blood sugar. Cells that make insulin also must work extra hard to keep blood sugar levels normal, which may cause these cells to dysfunction.
Peter Shepherd, chair of the editorial board of the Biochemical Journal, which published the latest study, noted that the researchers’ findings offer “important clues as to why some obese people go on to become diabetic while others do not.” In the future, “it will be interesting to see if similar correlations exist with other diseases associated with obesity, such as cancer and heart disease.”
Barbarroja N et al. Biochemical Journal 2010 Jul 28; 430(1): 141-49
National Institute of Diabetes and Digestive and Kidney Diseases