You can get all the protein you need from plants.  According to Dr. T Colin Campbell we only need 8 to 10% of our total daily calories from protein and we can get all we need from plants without the risks associated with eating animal based protein.  The WHO (World Health Organization) says the minimum need for protein in our diet is 5% and the optimal level of protein intake is between 10-15%. There is protein in lentils, nuts, seeds, quinoa, leafy greens, soy products like tofu, tempeh, and nutritional yeast just to name a few.  By eating plant-based proteins we decrease our risk of obesity, cardiac disease, diabetes, and osteoporosis.  These chronic diseases are all associated with eating animal based protein. The U.S. is eating a lot more animal protein than is needed for optimal health.  See questions below for foods high in protein.