How to Use the Body Fat Risk Calculator
The same body fat percentage doesn't mean the same thing for a 25-year-old and a 65-year-old, or for a man and a woman. This calculator uses age- and sex-specific body fat ranges from research such as Gallagher et al. to classify your number into underfat, healthy, overfat, or obese.
Women naturally maintain higher body fat than men, which supports reproductive function and hormonal balance. As people age, resting metabolism tends to slow and muscle mass declines, so body fat percentage naturally creeps up even at a stable weight. Applying a 20-something's benchmark to someone in their 60s would overstate their risk, which is why age-specific cutoffs give a more accurate picture.
Body fat that's too low is a problem too. Because fat plays essential roles in hormone production, temperature regulation, and protecting your organs, being severely underfat can cause irregular periods and reduced bone density in women, and weakened immunity or chronic fatigue in anyone. If your result comes back underfat or obese, it's worth approaching it as a body-composition goal rather than simply gaining or losing weight.
Frequently Asked Questions
Women naturally carry more body fat than men for reproductive and hormonal reasons, and as people age, muscle mass tends to decline while body fat rises, so the same percentage means different things at different ages. This calculator uses the age- and sex-specific ranges from research such as Gallagher et al.
Yes. Body fat plays essential roles in hormone production, temperature regulation, and organ protection. Extremely low body fat can cause irregular periods and reduced bone density in women, and both men and women may experience weakened immunity or chronic fatigue, so the underfat range deserves attention too.