Should the amount of protein consumed in a diet vary with more exercise? Would it make a difference if that exercise is strength training or cardio?
Protein is for repairing and building muscle, and not for energy. But as one exercises more, more muscle tissue would need repaired, so in theory, more protein would be needed, correct?
Conversely, would it make sense to eat less protein the more inactive a person is?
Protein is for repairing and building muscle, and not for energy.
This is not accurate. Protein is used for energy, but it is metabolically expensive. The body is going to choose easier energy solutions like carbs and fat if it's available, but if there's no choice it will break down protein for energy.
Conversely, would it make sense to eat less protein the more inactive a person is?
Yes. 1.6-2.2g of protein per kilogram of bodyweight is the recommended amount of protein for someone trying to build and repair muscle. The building and repairing requires more protein. Maintaining muscle mass takes less protein so people who have that goal can get away with less.
Should the amount of protein consumed in a diet vary with more exercise? Would it make a difference if that exercise is strength training or cardio?
There's evidence that endurance athletes such as marathon runners, ultra-marathon runners, long distance cyclists, etc. should probably eat more protein because the energy and recovery demands for these activities are so drastically high. Even for people eating intra-workout snacks as it's not really enough. Likewise professional athletes practicing their respective sport for many hours probably should as well. Though these people eat so much as it is that they generally get what they need without really trying.
The vast majority of people who are working out only do so for at most two hours, so they do not need to worry about increasing their protein requirements beyond the general recommended amount.
