Then how is everyone on MN a skinny rake? Because in the 'what have you eaten today' threads people are listing an apple and gasp of fresh air as a whole days worth of food, and when talking about clothes sizes everyone seems to say they're a size 8 
FWIW I'm a healthy size 10. Always have been, and probably always will be as I've already had my DC, but I eat like a normal person!
Also, I wouldn't say two thirds of my friends are overweight at all. They're my size or slightly smaller/larger but not by much. Where are all these two thirds of overweight adults hiding?!