i dont think its real, i think it has something to do with people thinking that if you eat meat then youll have more fat on your body, and seeing as THC is stored in fat tissue, they figured that the more fat tissue the more THC will be absorbed into the fat tissue and not able to float around your body doing what it does to get us high. but i eat meat, and im larger than most of my friends, and i smoke more than them and i still get more high than them sometimes.