“Because aging is associated with sarcopenia, the loss of skeletal muscle mass, relying on body weight alone is insufficient for the study of healthy aging,” said lead author Rania Mekary . . . “Measuring waist circumference is a better indicator of healthy body composition among older adults. Engaging in resistance training or, ideally, combining it with aerobic exercise, could help older adults lessen abdominal fat while increasing or preserving muscle mass.”
Prior studies had been focused on a specific population (e.g., overweight people or type 2 diabetics), were of short duration, and had mixed results. The new study was long-term with a large sample of healthy men with a wide range of body mass indexes (BMI).