How can I tell whether my weight is healthy for me?
Weight or BMI alone cannot establish health. BMI relates weight to height and is a screening tool interpreted alongside waist size, muscle mass, age, medical conditions and test results. Unintentional weight change deserves assessment even when BMI remains in the usual range.
Details
How is BMI used?
Divide weight in kilograms by height in metres squared. The usual adult reference range is 18.5 to below 25, but BMI does not directly measure fat or establish fitness or nutritional status alone. Some populations or circumstances warrant assessment at lower thresholds.
Important limitations
Children require age- and sex-specific interpretation. Pregnancy, high muscle mass and frailty in older people also change what the number means. Waist measurement can complement BMI when assessing central fat in appropriate individuals.
Aim for sustainable habits, strength and function. Avoid crash diets. Weight change accompanied by fatigue, digestive symptoms or eating difficulties calls for a broader assessment rather than a target number alone.
Related reading: Which preventive checks do I need when I feel well?.