Tofu, tempeh, and edamame Soybeans are considered a whole source of protein. This means that they provide your body all the essential amino acids it needs.
Animal Protein & Plant Protein
Plant proteins are considered incomplete because they do not have all of the essentials. But plant-based foods like legumes (including beans and peanuts), nuts, seeds, grains and vegetables still have varying amounts of protein.
Animal-based foods (meat, poultry, fish, eggs, and dairy foods) tend to be good sources of complete protein, while plant-based foods (fruits, vegetables, grains, nuts, and seeds) often lack one or more essential amino acid.
Avocados don't contain all the amino acids used by your body to build protein-based structures, but they contain all the essential ones. Essential amino acids must be obtained from the diet, whereas your body can make the non-essential types.
The casein in Greek yogurt is a complete protein because it contains all nine essential amino acids: methionine, lysine, isoleucine, histidine, valine, tryptophan, threonine, phenylalanine and leucine.
Oats contain all nine essential amino acids necessary to make up a complete protein. However, oats don't have quite enough of the amino acid lysine to qualify as a complete protein.
Incomplete Protein Foods. According to Harvard Health Publishing, all animal-based foods, including meat, dairy, and eggs, contain complete protein. The majority of plant-based protein sources, such as whole grains, legumes, seeds and nuts, spinach, broccoli, and mushrooms, are incomplete.
Surprisingly, potatoes offer a complete protein if you eat enough, over 10 per day. But you would ultimately encounter deficiencies in vitamins A, B12 and E, and calcium and selenium if you keep to just potatoes.
Chickpeas are a good source of protein.
Like most other plant protein sources, chickpeas are not a complete protein and do not contain all nine essential amino acids. Chickpeas are rich in some essential amino acids, including lysine and arginine, but lack the sulfur-containing amino acids, methionine and cystine.
The combination of beans and rice creates a complete protein. Beans alone and rice alone both lack certain essential amino acids. If eaten together, however, each contributes what the other is missing to form a complete protein.
Quinoa is a super grain for good reason. It is one of the few plant foods that is high in protein and contains all 9 of the essential amino acids while also being high in fibre, magnesium, B vitamins, iron, potassium, calcium, phosphorus, and many vitamins.
Moskovitz suggests combining corn, peas, tomatoes, chickpeas, edamame, kidney beans and onion with some oil and vinegar and serving over 2 cups of spinach for a meal packed with 27 grams of protein. Make a stir-fry with soybean tofu with baby corn, water chestnuts, bok choy, broccoli and teryiaki sauce.
Eating only one food probably won't do any harm in the short term. However, there is no known food that supplies all the needs of human adults on a long-term basis.
Stop Eating Mainly Processed Foods
One of the major dietary changes that have taken place in many countries over the last 30 years has been a shift to consuming more processed foods. Along with processing comes an increase in added sodium, more saturated fat, more sugar, and less fiber.
Vegetables high in protein include lima beans, bean sprouts, green peas, spinach, sweet corn, asparagus, artichokes, brussels sprouts, mushrooms, and broccoli. For more vegetarian and vegan sources of protein see the articles on beans and legumes highest in protein, and grains high in protein, and high protein nuts.
Guava. Guava is one of the most protein-rich fruits around. You'll get a whopping 4.2 grams of the stuff in every cup. This tropical fruit is also high in vitamin C and fiber.
Nut butter is also a source of protein, which is essential for building and repairing muscles. Although peanut butter is not a complete protein — meaning it does not contain all of the essential amino acids the body needs — it does count toward a person's daily protein intake.
Seeds are low-calorie foods that are rich in fiber and heart-healthy Omega-3 fatty acids. Chia seeds are a complete source of protein that contain 2 g of protein per tablespoon.
Grains, such as rice, oats, wheat, rye and corn, can act as complementary proteins for legumes such as lentils. They contain the cysteine and methionine that lentils lack, and lentils provide the lysine that grains do not contain enough of.