The amount of weight a patient must lose to achieve a target body mass index (BMI) can be calculated from current body measures.
body mass index in kilograms per square meter =
= (body weight in kilograms) / ((body height in meters)^2)
required change in body weight in kilograms =
= (current body weight in kilograms) - ((target BMI) * ((height in meters)^2))
Alternatively, since the height is constant:
target weight in kilograms =
= (target BMI) * (current weight) / (current BMI)
required change in body weight in kilograms =
= (current body weight) - (target body weight)
