Thats a very good question. The reason you can’t find a solid answer is because there are a lot of variables to consider. I’ll try to help give some input, but I don’t have any real research just my thoughts on it.
You want to know how much protein to eat at one time without “wasting” any of the precious aminos. And how long before you can consume some more?
I think it depends on the type of protein source:
BCAAs (not a complete source but I use them a lot) - I don’t take more than 5grams at one gulp but I will mix up 15grams in a water bottle and drink right before/during/immediately after my 1 hour long workouts.
Whey - I usually consume 40-50grams at the most.
Blended protein powders - I consume more around 50-65grams because they are releasing at different times over a longer period of time.
Steak or chicken - I usually eat around 50-60 grams but I don’t have a problem with eating more (up to 70-80grams).
Im a 200lbs guy who has been eating a high protein diet for years. If you are very new to eating a lot of protein like 1.5+ grams a day you will find it very hard to digest all of this protein at first. Your body will adjust and you will poop out less of it after a few weeks.
What you consume with your protein has a big effect. If you eat a fatty steak with some veggies (fiber) it will slow down the digestion and maybe block absorption of the aminos. But lets say you have a post workout shake with 50grams of carbs and some glutamine to spike insulin , then you are really going to absorb the aminos a lot easier.
Also eating some of the slower digesting proteins in high amounts fairly close together can tell your body its OK to push out the earlier meal and start work on the new one. (read if you eat too close together you will poop out the protein before fully absorbed).
Don’t eat a bunch of protein then go for a run because you will be forcing the blood away from your GI tract that breaks down and absorbs the protein.
After a really intense workout I tend to follow my post workout drink with a pretty big carb protein meal because I know my body is wanting a lot of protein.
I’m sure there are a lot of other things to consider and I’d like some input from someone with some real research too. As long as you don’t decide to consume 350 grams a day split between 3 big meals with a lot of fat and some Metamucil I think you will be alright. If you want to do it right you know you should have it split between 5-7 meals with a few carbs thrown in spread 2-3 hours apart.