Body composition is the relative proportions of fat mass, lean muscle mass, bone mineral density, and other tissues. It matters far more for long-term health, metabolic function, physical performance, and longevity than simply being “skinny” or achieving a low BMI. BMI (body mass index) is a crude height-to-weight ratio that often misclassifies people: it can label muscular athletes as “overweight” or, more dangerously, miss “normal-weight obesity” where someone has a healthy BMI but high body fat (especially visceral) and low muscle. Continue reading
