How Much Muscle Can I Make?

Muscle growth is determined by your genetics. You need food (calories), calories, rest and heavy lifting. Protein synthesis is also dependant on the person. What I need to gain muscle will be different than someone of the exact same height, age weight sex, ect. because of genetics.

The process of building muscle actually uses calories. Protein synth takes energy.

Think of it like this:
Protein - amino acids are the bricks
Calories are the workers

Without enough bricks you can't build anything, no matter how many workers you have. i.e. lots of calories and not enough protein will make you fat.

However a huge pile of bricks but only one worker wont get you very far. i.e. without a calorie surplus you'll be lucky to add muscle at any appreciable rate.

The key is to find an optimal speed where you gain decently with minimal fat.