Importance of Protein
Proteins from food sources play a major role in the proper growth and maintenance of the human body. The paradox is that although foods with high protein are inexpensive and easily available, a disproportionately high number of people are protein deficient. An understanding of the highest protein content food is therefore essential for healthy living.
The highest protein content food groups are grains, vegetables, fruits, nuts and seeds, meat, and egg and poultry products.
The US Food and Drug Administration (FDA) label food as “High Protein” if it contains greater than 10 grams of high quality protein per serving.
High Protein Grains:
Grains rich in protein include barley, brown rice, buckwheat, millet, oatmeal, rye, wheat germ, wheat and wild rice.
Vegetables with the highest protein content include artichokes, beets, broccoli, Brussels sprouts, cabbage, cauliflower, cucumbers, eggplant, green peas, green pepper, kale, lettuce, mushrooms, mustard greens, onions, potatoes, spinach, tomatoes, turnip greens, watercress, yams and zucchini.
Apples, bananas, cantaloupe, grapes, grapefruit, honeydew melon, oranges, papaya, peaches, pears, pineapple, strawberries, tangerines and watermelon rank amongst the highest protein content fruits.
Most nuts and seeds such as almonds, cashews, filberts, hemp seeds, peanuts, walnuts, pumpkin seeds, sesame seeds, and sunflower seeds have high protein content.
Meat & Dairy:
Most meat products have high protein, especially chicken, pork and beef and most fish fillets, shrimp and tuna. The highest protein content food are egg and dairy products, including eggs, milk, soy milk, peanut butter, yoghurt, cottage cheese and the like.
How to determine protein content of a food
One apparent way to determine the protein content of a food is to look at the percentage of total protein in relation to the rest of the macronutrients like carbohydrates and fats, fiber, water and vitamin and mineral content present in the food.
The protein content of a raw egg weighing 50 grams is approximately 12 percent of its total weight. Chicken breast, on the other hand has 23% of its total weight covered by protein content, whereas raw tuna steak has 23.4% of its total weight composed of protein content. Foods like soy protein isolate have as high as 80% of its weight covered by proteins.
The quantity of protein inside a food is however of secondary importance. The decisive factor is the quality of proteins inherent in the food, or rather the quantity of proteins inside in the food that is digestible by humans.
Among all the foods rich in protein, those that contain casein, whey and soy are of the most benefit, for these substances enhance the absorption of proteins to the human body.
In recent years, dietitians and nutritionists have recognized the Protein Digestibility-Corrected Amino Acid Score (PDAAS) as the most accurate measurement of overall protein digestibility in foods.
PDAAS uses a 0-1 point scale, with 1.0 being the most digestible protein and zero being the least, which roughly translates into a percentage of protein digested.
Eggs have a PDAAS of 1.0 implying that the human body absorbs 100% of the protein found in eggs. Beef has a PDAAS of 0.92 implying that the human body absorbs 92% of the protein found in beef. Wheat gluten on the other hand has a PDAAS of 0.25, implying that the human body absorbs only 25% of the protein in wheat gluten.
Plant sources of protein such as wheat gluten, vegetable proteins and nut proteins usually have low PDAAS whereas milk, eggs, whey and soybeans have a PDAAS of 1.0.
An egg weighing 50 grams would contain 6 grams of protein, all of which the human body would absorb. The same quantity of beans might contain 12 grams of protein, but the human body would actually absorb only 25% of the protein, or 3 grams. Thus, although beans apparently have higher protein content, the highest protein content food useful for humans is eggs.
While meat and vegetables might contain more quantity of proteins per serving, egg and milk contain the maximum quantity of “quality” protein absorbed by the human body per gram.
USDA Nutrient Database for Standard Reference, Release 15: www.nal.usda.gov/fnic/foodcomp/Data/SR15/sr15.html
Physicians Committee for Responsible Medicine: https://www.pcrm.org/health