Body Composition More Important Than BMI

Douglas Perry

Technology, Cycling, Swimming


A study that came out this year in the American Journal of Clinical Nutrition on the relation of body fat mass and fat-free mass to total mortality, is freely available for all to read and the findings confirm what most Breaking Muscle readers already know, BMI is not a good indicator of wellbeing or physical fitness.


In the study, higher instances of fat mass was associated with 50% more risks of mortality compared to lower fat mass. To put it in a better way, more muscularity is associated with lower risks of mortality.



The study is based on a 14-year follow-up on seven other studies and included about 16,000 subjects. So, while other studies have made similar observations, this body of evidence adds further weight to the arguments against the use of BMI, predominantly by insurance companies, to determine mortality risks.


BMI is a ratio, obtained by dividing weight, in kilograms, by the square value of height, measured in meters. Obesity is indicated by a BMI of 33-35, and above. A very muscular person can have a BMI of 25 and above, considered as overweight.



Body fat measurement alone may not be sufficient to determine the impact of your body composition on your health and the distribution of fat around the body is also a consideration, in particular the waist to hip ratio, where the greater the amount of fat around the belly the more impact on the mortality risk to the subject.


Body Composition More Important Than BMI - News, BMI, body composition, lean muscle


There are no simple answers to how your size and weight impacts your general health. There are guidelines, but what is clear is that there is a great deal of variance depending on ancillary factors including muscularity and fat distribution.


No two people share the same body and no two people sharing the same general statistics will have the same risk profile for mortality. You should look at yourself as a glorious experiment in personalization when it comes to training, goal-setting, and lifestyle choices. It's your life, and it has to be your way, the way that works best for you and only you.


More than any other factor, people new to exercise or fitness regimens should approach the process as a long-term experiment that will never end, carrying you through life at all ages.

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