By the mid-1960s it was clear that insulin was the primary hormone regulating fat accumulation, but by then obesity was effectively considered an eating disorder to be treated by inducing or coercing obese subjects to eat fewer calories. Once studies linked the amount of cholesterol in the blood to the risk of heart disease and nutritionists targeted saturated fat as the primary dietary evil, authorities began recommending low-fat, high -carbohydrate diets. The idea that carbohydrates could cause obesity (or diabetes or heart disease) was swept aside.
There is a lot of people that don't bloat up on even a gram of Test or 100mg Oxy's etc...It all comes down to your genetics, in some people Test seem to aromatize much quicker than in others. It also depends on your bodytype, It appears that in Endomorphs and Mesomorphs testosterone seem to aromatize easier than in Ektomorphs. It also depends on the amount of bodyfat that you hold prior to startng your cycle. The more fat you have around your belly the like that you are going to bloat up. I think this might be due to the fact that the aromatize enzyme gets stored in bodyfat.