In the popular imagination, Type 2 diabetes — and diabetes generally, for those who don’t know the difference between Type 1 and Type 2 — is often associated with being overweight or obese. As the thinking often goes, gaining a large amount of weight means risking an imminent diabetes diagnosis, while maintaining your weight or gaining it gradually is safer. According to a study released last week, however, while there is a correlation between overweight and diabetes, the pattern may be more complex than even many scientists had previously believed.
Published in the February edition of the journal PLoS Medicine, the study examined medical data from 6,705 British civil servants between the years 1991 and 2009. All participants were white and based in London, and none had diabetes at the start of the study period. By the end of the study period, 645 had developed Type 2 diabetes. The researchers examined weight changes in these participants in the months and years leading up to their diabetes diagnosis. According to an article on the study at WebMD, all participants who developed diabetes fit roughly into one of three groups: “stable overweight,” or those whose body-mass index (BMI) stayed relatively constant leading up to their diagnosis; “persistently obese,” or those whose BMI classified them as obese, not just overweight, throughout the study; and “progressive weight gainers,” or those who gained weight throughout the study period.
“Stable overweight” was, by far, the largest group of participants who developed diabetes, at 604 people. Another 26 were “persistently obese,” and only 15 of the 645 participants who developed diabetes were “progressive weight gainers.” In the “stable overweight” group, the researchers found only slight increase in insulin resistance, on average, in the five years preceding participants’ diabetes diagnosis. “Progressive weight gainers,” on the other hand, had a huge increase in insulin resistance leading up to their diagnosis, suggesting that it is not necessary to gain a large amount of weight at once to experience a sudden increase in insulin resistance. “Persistently obese” participants didn’t experience much insulin resistance throughout the study period, suggesting that the correlation between insulin resistance — long considered a hallmark of Type 2 diabetes — and Type 2 diabetes itself may also be weaker than most scientists imagined, at least in some groups of people with diabetes.
Of course, there could be factors not examined by this study that might help explain some of its results. One such factor may be the type of body fat seen in different groups of participants. As we’ve discussed here at DiabetesSelfManagement.com, not all body fat is created equal: Abdominal fat has been shown to be much more metabolically dangerous than fat around the hips and thighs. But if the study’s findings are taken at face value, they mean that the biggest weight-related danger when it comes to Type 2 diabetes isn’t weight gain or obesity, but simply being overweight for a substantial period of time.
What’s your experience when it comes to your weight and diabetes — did you experience weight gain leading up to your diagnosis? Was your weight stable before you found out you have diabetes? Were you ever told that modest weight loss could reduce your risk of developing Type 2 diabetes? If not, do you think you would have behaved any differently if you had known about the diabetes-related risks of being overweight? Leave a comment below!