Dr Keith Souter writes: Most people are aware of the Body Mass Index or the BMI.

Source: https://www.dewsburyreporter.co.uk/health/drs-casebook-you-can-be-thin-on-the-outside-but-fat-on-the-inside-4228828

It is a combination of factors: such as gender, age, BMI (Body Mass Index) and body fat.

Source: https://www.ndtv.com/partner-content/health-supplements/best-diet-pills-for-men-2023-top-male-weight-loss-supplements-for-perfect-body-3976058

She and the rest of her group are happy for her friend, too, even though her friend’s weight loss goal is pretty extreme and will leave her friend with a Body Mass Index (BMI) that is underweight.

Source: https://www.chipchick.com/2023/06/she-finally-told-her-friend-who-believes-most-girls-are-jealous-of-her-that-they-really-arent.html