Being Overweight Just a Bit Isn’t so Bad

January 21, 2013

Being Overweight Just a Bit Isn’t so Bad

 Referenced: Flegal JAMA 2013 Carnethon JAMA August 2012, Reuters Health News 

 We have always said that your BMI was the easiest way to measure if you are a bit overweight. The sweet spot of BMI is about 22. You can calculate your BMI by measuring your weight in pounds divided by your height in inches, squared – then multiply by 703. (This makes up for the metric system measurement that has weight in kilos divided by height in meters, squared.   

A BMI over 25 means you are overweight and over 30 means you are obese. The term “overweight” suggests that you are not ideal, and there are consequences to this. Hmmm. Not so fast, says Dr Flegal in the JAMA study from earlier this month. She looked at almost 100 studies covering some 3 million people for mortality related to weight. Over 270,000 deaths occurred during this time period. It would be hard to duplicate this study and find different results as this study is so massive.  

And what she found was that there is a LOWER mortality for those whose weight is in the BMI range of 25-30, and that folks with BMI of 30-35, mortality was about the same as those in the 22-25 range. This is startling. This really pulls the rug out from previous assumptions about overweight and what its range should be. Where does the confusion come from?  

The clue may well come from the Carnethon referenceabove. Mercedes Carnethon looked at mortality related to having diabetes, whether you are overweight or not. It appears that this may ferret out some of the confusion. What Carnethon found was that folks who were normal weight, but with diabetes died at a much higher rate than if they were overweight. It may not be the weight, per se, but how your body handles it.   

There is a pretty clear connection with being overweight and becoming diabetic. That is known. So it’s easy to make the inference that being overweight will automatically lead to being diabetic. But it doesn’t. Some escape. And it appears that being diabetic and normal weight is really a problem. That occurs in folks who are “metabolically obese but normal weight”. They have little muscle mass and lots of visceral fat. The good news is that lifestyle changes can modulate all of this. Folks who are normal weight but metabolically obese can find out how they are doing by getting a body fat measurement, instead of just weighing themselves. A blood sugar, a blood pressure and cholesterol testing will assemble the whole picture of whether your body handles it or not. The cure? Reducing your body fat and increasing your muscle mass makes all the difference in the world. The key is exercise, better eating, avoiding carbs……you’ve heard all this. 

 WWW. What Will Work for Me? You know the answer. We are now becoming much more aware of glucose changes at even subtle levels. When I exercise, I can see my blood sugar drop as much as 10 points in a day. Same when I get off all white bread and sugar. My BMI is 25.5. Almost “perfect” but my body fat percentage is 19%, at the very top end of “ok”. That may be why my blood sugar and tendency to be diabetic is just hovering at the edge of trouble. I’m at the edge. I would rather stand back a bit from that edge.


Column written by Dr. John E. Whitcomb, MD, Brookfield Longevity, Brookfield, WI