Jesus Christ this day and age and we are debating this bs. 3 things work consistent exercise, sufficient (minimum) food and peds.
if you exercise, you are not fat because of what you eat. your natural growth hormone and insulin production decide how much fat you hold. your performance depends on having ENOUGH calories and natural testosterone production to have muscular hypertrophy after the training stimulus.
you can be -10% body fat and muscular if your genetics allow you to be. bodybuilders have known this for years.