What we've been led to believe is that fat consumed will lead fat on the body and more so than the other macronutreints, protein and carbohydrate.

What we've been led to believe is that fat consumed will lead fat on the body and more so than the other macronutreints, protein and carbohydrate. However human metabolism is more complex and in fact it's excess carbohydrate that causes fat to accumulate than fat. Can you provide an explanation for this? There are two primary reasons.