Digesting a certain amount of protein per meal

"I can only digest 20g of protein per meal". For some reason, this comes out of a lot of people's mouths. Now I'm not saying some of you are wrong, I'm just quoting a doctor.

"I have no idea how this myth got started, but there's simply no data that i know of to support the idea that a normal-sized person can only digest 20g of protein at a time. If that were true, bodybuilders who eat 400g of protein a day would have to eat 20 meals a day! In reality, this is a silly misconception because protein is used for much more than building muscle. protein has thermogenic effects(that is, it helps promote weight loss if calories are reduced), helps blunt appetite and has beneficial effects on glucose control and blood lipids. My hunch is that most people who promote this myth really want to know how much protein they need to eat to mazimize the muscle-growth response. Unfortunately, scientists really don't know the definitive answer to this question. For whey protein, it's somewhere around 40g per meal. For egg protein, it may be a bit lower (20g). But the few studies that have been done used only untrained men who performed a relatively low volume of resistance exercise. For now, the two most important things to remember if you are trying to gain muscle are: 1) never train fasted; and 2) get some high quality protein in the tank immediately after training (20-40g)"

- Doctor Ziegenfuss