BMI not a great metric for obesity in very muscular people

Dear Dr. Roach: I am a 65-year-old disabled veteran. I have lost 40 pounds and 4 inches off my waist in the past year so I can have knee surgery. But the Veterans Affairs uses the BMI as the only metric to determine body fat, so I am still categorized as “obese.”

I stand 5 feet, 10 inches with a 58-inch chest and 42-inch waist. In school I was defensive nose guard and catcher. My question: Is the BMI valid as a stand-alone metric to determine body fat? — D.W.

A: The BMI (weight in kilograms divided by height in meters squared) is a reasonable metric for obesity, and at a population level, it is a reasonably good predictor of developing diabetes and even overall mortality. However, it is not perfect, and one of the most common failures is when it is applied to very muscular people. There are people who really are “big boned,” but it’s the musculature that makes the weight go up.

Among professional American football players, even those with very high BMI levels may have very low amounts of body fat, as measured by an accurate method. In your case, the waist of 42 inches suggests that you may still have an excess of body fat, despite your excellent job of losing weight and inches off your waist.

The VA is a law unto themselves as far as determining who qualifies for procedures. Nothing I say is likely to change minds there.

Dear Dr. Roach: As I’ve aged, I find sleeping to be more and more difficult. When I take a product whose chief ingredient is diphenhydramine, I sleep well with no side effects, but I worry about longterm consequences. Is this safe to take daily? — T.C.

A: Most people take diphenhydramine and have no problems; however, I still don’t recommend it, especially for older people. These drugs increase the risk of falling, lead to a higher risk of motor vehicle collisions, and may cause symptoms of confusion and dry mouth. Men who take this can have decreased ability to urinate. Although there are some studies that suggest an increased risk of dementia with use of this product, I don’t think it is likely to be a big risk.

Whenever possible, I recommend avoiding medication and focusing on behavioral techniques that have been proven effective: have a regular sleep schedule; don’t try to force sleep; avoid alcohol and caffeine near bedtime; and don’t use bright lights or computer screens before bed.

Finally, many older adults need less sleep. If you are sleeping fewer hours than you think you should be but aren’t sleepy during the day, then you are likely getting enough sleep.