The most concentrated forms of protein in the human diet are animal-based foods like fish, meat, eggs and dairy products. Some of the most popular protein sources for athletes include lean steak, venison, skinless chicken or turkey breast, ostrich, tuna, eggs, and cottage cheese or yogurt.

On average, beef steak contains about 23 grams of protein per 3-ounce serving, while the same amount of pork provides 26 grams of protein, and chicken provides about 24 grams. Meat normally contains all nine of the essential amino acids our bodies need to get from food.

Fruits, vegetables, grains, nuts, and seeds contain significant amounts of protein, but individually usually lack one or more of the nine essential amino acids. Experienced vegans and vegetarians make a practice of combining these incomplete protein sources to form complete proteins.'s article "Simple Guide to Choosing Complementary Proteins" can show you the most common ways to build complete proteins from plant-based sources

However, as long as you eat a diet that contains a wide range of vegetable proteins, you probably don't need to worry about creating complementary proteins at every meal. High-quality vegetarian protein sources include quinoa, buckwheat, hempseed, chia seed, soy, Ezekiel bread, mycoprotein (Quorn), rice and beans, seitan, spirulina, many grains or nuts, hummus and pita and, last but far from least, the good old peanut butter sandwich. Even green vegetables like broccoli and asparagus offer a decent amount of protein.

Many vegetarians and vegans also use plant-based protein powders to help ensure they're getting adequate amounts of essential amino acids, and protein in general. However, for them, it may be beneficial to occasionally use blended vegetarian protein sources, such as a powder that contains both pea protein with a rice protein, to cover all their amino acid needs.