Calories in vs out is wrong because those who tote it assumes that only physical exercise has an effect on calories "out". New research shows that the human body is keenly aware of the amount of energy available and adjusts many bodily functions (tissue repair, heat, hair growth, immune defense, etc) accordingly. This is why just restricting calories in and exercising more won't necessarily mean you loose weight.

Taken literally calories in vs out is of course true.