Calorie calculation based on body fat and muscle composition.

It would be quite beneficial for athletes to add body composition parameters like fat and muscle. So the application estimates the required calories based on not only genger, height, weight and activity level. For example i would describe my life as low activity as i work beside desk, but i train 4 times a week with purpose of gain muscle. But i can only add my overall weight, it would be amazing to see how my muscle weight is growing and fat weight is shrinking, also to get a detailed nutrition plan on how much i assumeably need to eat to maintain weight but modify the composition.