BMI Key < underweight to healthy 25 to overweight * 30 to grade 1 obesity 35 to grade 2 obesity > 40 grade 3 (morbid obesity)
@Alvin – That’s a great question. From my own experience with my training clients, I never had one client lose an ounce of muscle while losing fat (well actually one who tried a very low carb diet when he was already lean). This is because they did intense strength training, did not go too low on the calorie deficit, and ate sufficient protein (roughly per pound of body weight). I think if you follow these 3 guidelines, you can keep the vast majority of your muscle mass. As you start getting around 10-12% body fat, it’s very possible that you lose a little muscle mass. So let’s say a bodybuilder looking to get shredded for competition may lose 3-5lb of muscle as he strips his body of all the fat he can.
BMI Prime, a modification of the BMI system, is the ratio of actual BMI to upper limit optimal BMI (currently defined at 25 kg/m 2 ), ., the actual BMI expressed as a proportion of upper limit optimal. The ratio of actual body weight to body weight for upper limit optimal BMI (25 kg/m 2 ) is equal to BMI Prime. BMI Prime is a dimensionless number independent of units. Individuals with BMI Prime less than are underweight; those with between and have optimal weight; and those at or greater are overweight. BMI Prime is useful clinically because it shows by what ratio (. ) or percentage (. 136%, or 36% above) a person deviates from the maximum optimal BMI.