>From plant sources, most will only give you some of the ones you need (soy being an exception).      This is incorrect. All proteins provide all the essential amino acids. Different plant proteins just have different ratios of them. So if you got all your protein from lettuce and only got the minimum amount of protein needed, then you would be deficient in certain amino acids. Most people, even vegans, get well over the amount of the minimum protein necessary.     If you got all your minimum protein from lettuce, you would fall short in methionine, but you would have only eaten 550 calories.