The human body is more than capable of absorbing 60 grams per meal given the time. Only a very, very small amount is not excreted into the feces. You also have to look at what type of protein it is. 60grams of whey is going to absorb much quicker than 60 grams of red meat or cottage cheese, etc. So, you can't eat some red meat and in 20 minutes hope it is all digested and absorbed. Likewise you can still refeed with more protein without it all being absorbed from a previous meal, the accumulative build-up of undigested food will get absorbed at some point....usually once you are asleep with the over night fast.
Carbs are a little more complicated. ANy insoluble fiber carbs will get shuttled out as bulk in the feces. Soluble fibers will as well to a lesser extent but both can break down into short chain fatty acids in the colon/large intestine. Some simple sugars such as those found in sports drinks can cause a dumping syndrome by drawing water into the intestines, which can cause diarrhea. Some starches such as amylose, found in most whole grains, noodles, etc....are resistant starches and will not get absorbed.
Most other carbs will absorb fairly well in the small intestine given enough time just like proteins.
The timing is the major factor, and then you have to consider that most foods will also have a mix of fiber, proteins, starches, fat in the meal which can affect the absorption and absorption rates altogether themselves.
That being stated....just eat my friend....Lots of FOOD
BMJ