The statistic sounds alarming: More than two-thirds of American adults are overweight or obese, according to the National Institutes of Health. Overweight and obesity are, of course, risk factors for a number of diseases and conditions, including Type 2 diabetes, cardiovascular disease, osteoarthritis, and some types of cancer. Often, media outlets and some health professionals act as if this is the whole story, and that having a “normal” body weight is desirable in all cases. But a trio of recent studies show that the picture is a bit more complicated than this.
One of the studies, published earlier this month in the journal The Lancet Diabetes & Endocrinology, looked at the relationship between body weight and risk of dementia in middle-aged and older adults. To reach their findings, researchers analyzed a database of nearly two million patients in the United Kingdom, representing 9% of the British population. The average age of patients in the database was 55. According to an article on the study in Diabetes In Control, over an average period of about nine years, just over 45,000 participants were diagnosed with some form of dementia. Participants who were underweight, defined as having a body-mass index (BMI) below 20, were 34% more likely to be diagnosed with dementia than normal-weight participants (BMI between 20 and 25). But above this supposedly ideal weight range, the risk of dementia declined even further, with very obese participants (BMI above 40) 29% less likely to get dementia than normal-weight participants. It should be noted that people with diabetes are already at an elevated risk for dementia.
Two other recent studies focused specifically on weight differences among people with diabetes. One, published last month by the journal Medical Care, looked at how much health care — including office visits, hospital procedures, emergency room visits — people both with and without diabetes at different levels of BMI consumed. Among people with diabetes, health-care spending was significantly lower among obese people than among normal-weight people. Among people without diabetes, however, being obese resulted in slightly more health-care spending than being of normal weight. This result indicates that diabetes may be more difficult to control, or may have more negative consequences, among people with a normal weight than among those who are overweight or obese. Similarly, a study published earlier this week in the journal Nutrition & Diabetes found that in a survey of people with diabetes, those with a normal body weight rated their own health as worse than did those who were overweight or obese.
It’s worth noting that past studies have also found an association between higher BMI and a lower risk of overall death among adults in the general population. While the reasons for this association are unclear, part of the reason may be that not all body fat is the same — belly fat, for example, is widely considered harmful, while fat deposits in other areas of the body may be neutral or even protective when it comes to your health. It’s also possible, however, that overweight and obese people are simply more likely to receive medical attention and live longer as a result.
What’s your impression from these studies — do you think you’ve heard too much about the dangers of being overweight? If you’re a thinner person with Type 2 diabetes, do you feel that your diabetes is especially difficult to control? If you’re a higher-BMI person with Type 2 diabetes, have you noticed any changes in your diabetes control that accompanied weight changes? Are you concerned about the risk of dementia associated with diabetes, and if so, are you reassured or dismayed by the finding that having a higher BMI may be tied to a lower risk of dementia? Leave a comment below!