How much protein a person needs?

: Your body can only use a certain amount of protein per meal. If you are exercising, obviously your body will require more protein. : If you are eating 80grams of protein after you exercise, lets hope you are Mr. Olympia. Or your body will not use most of that. : The calculation is - the typical healthy person require 0.8 grams of protein per kilo of body weight (2.2lbs). So if you are 145 pounts, you would only require 60g or protein after a workout, as an above normal intake. : If you think about it, a typical protein shake only has 20 or 30 grams of protein each scoop. And 1 protein shake of 2 scoops with milk should be more then enough after a workout.
About 3/4 gram for each kilogram of lean body mass if you are sedentary and about 2 grams for each kilogram of lean body mass if you are an active athlete or body-builder.

The USA and Canadian guidelines suggest for women aged 19-70 need to consume 46 grams of protein per day, while men aged 19-70 need to consume 56 grams of protein per day.