As we often point out, causation does not mean correlation. That’s why epidemiologic studies quite often have nothing to do with science and reality.
One of the often reported piece of data when talking about obesity is that people with higher BMI seem to live longer, and by many is considered the proof that being fat isn’t actually unhealthy.
Now, BMI as we know is not a very good index of anyone body fat percentage, since it’s only based on height and weight. A bodybuilder has a very high BMI even the day of a contest with 6% body fat, while a sedentary man with very little muscle mass could be considered normal even with a body fat of more than 30%.
Yes, we do offer a free BMI calculator on this website, but it should only be used to give you an idea of your body fat percentage for the purpose of calculating your macros, with the goal of weight loss.
Now, let’s go back to the fact that a higher BMI is correlated to a longer life.
A new research suggest what many people already thought: the people living longer with a higher BMI are the ones with more muscles, not with more fat. The BMI index doesn’t differentiate between fat and muscles, but it only looks at the weight.
The study measured the body composition of the subjects with similar BMI and concluded that muscle mass levels are inversely associated with the risk of death.
Sarcopenia (loss of muscle) was already associated with all cause deaths in elderly people, and this research confirms the importance of a protein rich diet at all ages, even better if associated with resistance training.