Easy – Protein only has 4 calories per gram in it. Even a 200g/day protein goal (which is likely more than enough for most people) is only 800 calories in total. This leaves plenty of room for carbs and fat.
If you’re having trouble figuring out what to include in your diet, a good place to start is to do a Google search for “high protein foods”. Protein shakes are very commonly used to meet high protein goals conveniently, and are – no lie – nothing more special than just plain old protein. Also make sure to click the link above and make sure you’re not trying for a protein goal that is too high to be useful.
For further reading from Reddit users themselves, you can find some great advice in our Community Campfire threads archive.