Calories do count. You need to supply your body with enough fuel to carry you through your daily activity and exercise. Fat tissue is the body's preferred choice. On the other hand, eating too many calories will cause unnecessary weight gain. Consuming adequate protein means that you are sparing carbohydrates as a source of fuel, forcing the body to use fat for energy.
Dietary protein is also the building block for muscle tissue.
If your protein levels are too low, your muscle tissue will be broken down for fuel when your carbohydrate stores are exhausted. Meanwhile, your body thinks it is going into a crisis and begins to store fat. These processes happen simultaneously in your body's effort to maintain equilibrium. Fat has some very important functions in the body, including absorption of fat-soluble vitamins and maintaining nervous system integrity. On the other hand, the amount of fat, especially saturated fats, in your diet needs to be moderate due to the negative implications it may have, including fat tissue storage and cardiovascular disease.