Unfortunately, it's not simple in that it depends on what your goal is. Protein is important, as you cannot build muscle without it, but caloric intake is what determines energy levels and body fat. So the "simple" answer is
both.
I'd spend some time learning about what your TDEE (Total Daily Energy Expenditure) is, as that's a rough calculation based on a few of your statistics and exercise levels. This number tells you how many calories your body needs to maintain its current state, and serves as a starting point from which you can decide to reduce for fat loss, or add to for increasing weight.
The best approach I've found is to take small steps in the chosen direction and gauge results. Then make changes based on how things are going. The rule of thumb is roughly 1g-1.5g of protein for every pound of lean mass, as this is usually sufficient for most. After that, you can decide to budget in your other macros as Tron stated to fit your needs. (carbs are the cheapest source of calories, so they tend to get the lion's share of the macro split)
My .02c