Vegan

yes, I was thinking in the context of an athlete who wants to build and maintain muscle.

I agree, the importance of protein is overblown in America where the average person consumes way too much protein, and this warped perception is then weaponized and often used as a false pretense to shut down the idea of being vegan or, even more ridiculously, vegetarian.

However, I also have recently re-engaged paying attention to protein in the context of how filling food is relative to its protein content, how long a meal sustains my energy and mood, and how important protein is to body-shaping and bulking muscle.

I have found it surprisingly hard to get vegan protein sources that are high-protein and low carb when focused on using whole / non-processed foods.

Obviously it's not too hard when you eat processed foods, Just Egg for example has a ratio of 5 grams of protein to 1 gram of carbs. Beyond Beef has a ratio of 2.6:1, and your typical vegan seitan lunch meat has the same ratio. You can also just buy vegan protein powder, easy (I use pea protein powder).

For comparison, black beans have a ratio of 0.37 to 1 (so more carbs than protein). Edamame and soy beans are the best, closer to 1.5 grams of protein to 1 gram of carbs.

You might turn to nuts and seeds, but then the problem is just swapping fats for carbs: peanuts, cashews, pumpkin seeds, etc. are all great sources of protein but still have more grams of fat than protein (so it's hard to get a lot of protein without getting a lot of fat, and thus too many calories in that meal from the fat).

Metabolically fats in moderation seems theoretically fine, but foods where most of the calories come from something besides protein makes it harder to get enough protein.

I weigh my food and track my macros, and even with a reasonable / moderate goal like 60 g of protein per day, I often fall below that (particularly when focused on eating whole foods). That's where incorporating processed substitutes makes this so easy (you know, impossible meat, beyond, Just, tofurky, field roast, etc.), I never struggle to get enough protein on those days because they use refined protein isolates to get closer to the protein content of meat.