Maybe I'm over thinking this but I'm eating 268g of protein per day over four meals(non lifting days). I weigh 205lbs. My concern is that if we can only absorb so much protein in one sitting, am I absorbing enough protein each day? I've read 30g per meal is about all you can absorb. 30g per meal for 4 meals is only 120g of protein per day. Surely I don't need to eat 7 meals though.
The 30 gram per meal guideline/myth/rule of thumb/urban legend/whatever MIGHT HAVE SOME BASIS IN FACT (all caps for those who want to argue).
Of your whole small intestine, protein is mainly absorbed by only the first 2/5ths, called the duodenum and jejunum. Once your meal gets to the ileum (3rd part of the small intestine), protein absorption drops dramatically. Several studies claim whey protein absorption at 10 grams per hour, and something similar for pork loin (but take the pork results with a grain of salt). So, the question is, how long does a meal spend in the duodenum and jejunum?
The answer is: It depends. It depends on the gastric emptying rate (how fast the stomach releases the food into the small intestine), the peristaltic rate (how fast the waves of contractions in the intestine move food along), and sometimes the previous contents of the small intestine (i.e. roadblock). The best answer I came up with is about 3-4 hours awake, and 6-8 asleep, however it's actually quite tough to find a good answer to the question of how fast food moves through the small intestine.
So while lots and lots of people will tell you the 30 gram limit is horse puckey, I'll tell you there just might be a grain of truth to that old rule of thumb. In general, eat some fats with your protein, they slow gastric emptying. Eat some solid food with every protein shake, as it'll slow things a bit too. If you're only using 30-40 grams of whey at a time between meals then it's probably not something to worry about. However, if you think about it, there are 24 hours in a day... 10 grams per hour... math says 240 grams is about the limit, depending on how big your intestines are (they scale with height, not weight).