It sounds like the old Body Mass Index (BMI) concept is coming up again. My understanding of this thing was that it was originally invented in the 19th century by Adolphe Quintelet, but it was ignored in most Western countries in favour of weight versus height and frame size tables developed by various bodies like insurance companies. Then in the 1980s the World Health Organisation (WHO) revived the BMI idea and the medical profession have gone along with it. The problems with BMI are:
a) It doesn't really apply to anybody who is more muscular than average. There was a study suggesting the overweight threshold of 25 and obesity threshold of 30 should be increased to 28 and 33 for certain categories of sportsmen.
b) The basic assumption in BMI that weight is proportional to height squared is dubious. If a human body is idealised as a cylindrical volume and the radius is proportional to height, then weight should be proportional to height cubed. Some studies have shown that weight is proportional to height raised to a power between 2 and 3, e.g., the study on this link comes up with a power of 2.6:
c) The overweight threshold of 25 and obesity threshold of 30 tend to be applied in a politically correct, 'non-racist' manner. In the USA, the overweight threshold was taken as 27.8 up to 1998 but the US medical profession then decided to adopt the WHO 25 figure. For slender south east Asian body types, an overweight threshold of 25 is considered by some to be too generous and 23 is more advisable.