
Originally Posted by
Demonakat
While you're working out, cardio or strength, your body turns carbs into ATP and then breaks those bonds. I could go into a more detailed analysis of how it does that, but I'm lazy. Carbs are ALWAYS the first to be burned. Proteins are amino acids, they get used up to rebuild cells. Fat is there to turn into fat. Your body will burn protein and fat when it's done with the carbs, but carbs are always the first to be used for energy, simply because they're the easiest to break down and be used for energy.
If you're trying to get up to 5k Calories a day without going over 150g of carbs, you need to consume more fat in your diet. You would get too full/sick from consuming too much protein.
Alcohol is 7 calories per gram, but that would also make you sick.
The best energy source would be, simply, carbohydrates. But if you're dead set against it, you need to take in more fat. Which is something I NEVER recommend, but if that's what you want, that's what you want.