Is there a relationship between an ideal range of body weight, body mass index, muscle mass, fat mass and health & longevity, or is it all a mystery resulting in an “obesity paradox”?
I am not a researcher in the field, but in my opinion the so-called “obesity paradox” is another area of research that is in desperate need of more qualitative analysis. We can start by using a relatively simple body composition assesment. It need not be costly.
The study that came out this past week, spurring me to write this post, was a meta-analysis of 32 studies looking at adults over 65 years of age and their risk of mortality (death) based on their BMI. The researchers found people at the high end of a healthy BMI range 24 – 31 were at lower risk of mortality, and those below 23 were at highest risk. The magic number with the lowest risk for death was 27-28.
There may indeed be some benefit for older people to have a BMI higher than is currently recommended for a younger population. I believe we will have a better answer to that question in time, and I speculate it will show a higher BMI is advantageous when muscle mass is also factored into the equation. There was another recent study published last month suggesting this is the case.
In this study, researchers used a muscle mass index, which is the amount of muscle relative to height. Sure, it would have been nice to include non-lean mass in the equation, but it’s a start. They analyzed data from men 55 years of age and older, and women 65 and older. They found people with the highest levels of muscle mass had a significantly lower risk of death.
As I have written on the past, “People need to pay more attention to acquiring lean muscle mass and spend less time worrying about how many pounds of fat they have to lose. Pursue the growth and development of healthy muscle tissue, and the healthier metabolism that this engenders. The rest will likely fall in place, including reduced body fat.” And longevity?
Although I am sensing a slight change, the importance of some resistance training for adults is not generally advised by health care professionals. I suspect this is in part due to the principle of primum non nocere – “first, do no harm.”
I dare say most health professionals have never engaged in weight training themselves, and it’s safer to tell a patient, “Walk for exercise.” Health professionals need to step up their game in this area, and learn how to safely encourage some forms of resistance exercise for the health of their patients.
It’s important to note the above studies merely point out correlation, not causation.