When I tell anyone that I'm a Vegan or on a plant based diet, I am always asked the number one question of all time (in this subject) : "Where do you get your protein from?" It's amazing that the average person thinks this is the most important nutrient in the world, and that if one is a Vegan or vegetarian, that they must surely be lacking in protein, and therefore open to a whole range of serious diseases. The truth is that humans eating the SAD diet (Standard American Diet) are getting far too much protein. The average plant based diet is approximately 70% complex carbs (the "good" carbs) , 15% fat, 15% protein. That's not very much protein...but sufficient for proper health. The reason people go around thinking we need so much is that we've been told we need a lot and have been sold a bill of false goods by the meat and dairy association over the years. Doctors are not taught nutrition in schools, and doctors, as well as the average person out there, also think we need more protein than we do, yet most will admit the consequences of getting too much of it. If they're aware of these consequences then why don't they recommend a low protein diet? The consequences of too much protein (animal protein) can include osteoporosis, kidney failure, kidney stones, heart disease, stroke, and certain cancers (breast, prostate, colon to name a few).
There is a myth that plant proteins are incomplete. That's what it is really, just a myth. I'll go into that soon enough. Studies have shown that animal proteins can increase the risk of cancer while plant proteins do NOT.
So when asked about where do I get enough protein, the answer is we get all we need from plants! Grains, vegetables, beans, legumes, greens, seeds and nuts supply all the protein we need. I've heard many a plant based nutritionist say we should be more concerned about how to get LESS protein than more. Even many Vegans worry about it too much, or eat too much plant protein...as found in tofu, seitan, or tempeh. We don't need any of these high density protein foods really...they are all processed, not found in nature in a pure and edible form, and not necessary to have in our diet. People think we eat tons of tofu, as they always follow up their question about where do we get our protein from, with the statement "do you eat a lot of tofu?" I usually say no, or almost none and that it's not necessary either.
The high protein diet fads that seem to always come and go (Atkins being the most obvious) can cause serious overloading of the kidneys leading to kidney failure in the short term, and atherosclerosis and other heart issues in the long term. Colon cancer is now recognized as being directly related to a high animal protein diet. The simple explanation being that animal protein has no fiber (ZERO) and therefor does not move very swiftly through our bodies. The rotting flesh takes forever to break down and sits in our colon eventually and leads to colon cancer (simple explanation, but close enough) I once heard a well known nutritionist, George Eisman, state that the correlation between animal protein to colon cancer, is as positive and closely tied as the correlation of smoking to lung cancer. The odds and effects are almost similar.
Another well known plant based doctor told his audience to try to leave the word "protein" out of our vocabulary. Forget about thinking about it and forget about worrying about it. If you eat a well balanced, nutritionally adequate plant based diet , you will be getting all the protein you need. Dr. McDougall has said that it is impossible to NOT get enough protein if one eats a well balanced nutritionally adequate plant based diet!