h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

As mentioned in this entry, BMI is a guide only. In fact, it is a rather flawed guide.

BMI is calculated by dividing one's mass in kilogrammes by the square of one's height in metres. Thus I, for example, would have a BMI of around 26.85 kg/m^2 (mass=87kg, height=1.8m). However, since muscle is heavier than fat, this means that somebody who is *extremely* fit as a result of lots of exercise could have a BMI that makes them look overweight, simply because they have really big muscles.

Although I suppose this fact is more important for men, since we bulk up much easier than women.

(By the way, I'm not *extremely* fit; in fact, I think I could stand to lose a couple of kilogrammes, but, well...whatever).

Hi there, we did discuss this in the PR thread, it works the other way as well, in that there can be people who are thin and the BMI will indicate they are underweight, but they're just a very fine build.

I call them bird-bones, those tiny people who look like you could blow them over but are perfectly healthy.

Doctors in the UK now recognize that BMI is *not* a good guide to whether somebody is overweight. They look at the muscle tone on each patient to assess whether the BMI is down to fat or muscle. For example, George Clooney has a BMI of over 25, yet hardly has an ounce of fat on him. I have a BMI of 28 and I want to lose 25lb (losing 18lb would take my BMI below 25 - just).

Yeah, it's just a guide and a doctor can tell more about you by just looking at you than the BMI - I think that's why London fashion week didn't ban any models - they are supposed to be self-policing

with the weight loss, just remember it's about a lifestyle change not a diet.