Many different foods contain protein. Meat, fish, eggs and dairy are animal-based protein sources. Plant-derived proteins include soy products, beans, grains, nuts, seeds and some vegetables. Fruits don't contribute significant protein to your diet, but they do add valuable fiber, vitamins and phytochenicals. For optimal nutrition, you should consume a variety of fresh fruits and vegetables, lean proteins, whole grains, beans, nuts, seeds, and dairy products or equivalents.
Meat and Fish
Most forms of animal flesh have significant amounts of protein. Chicken and beef may contain 18 to 35 grams of protein per 100 grams. Fish have approximately 15 to 20 grams of protein per 100 grams, and many fish also contain heart-healthy omega-3 fatty acids. Although meats have substantial amounts of protein, they also can be high in saturated fats. Choose skinless poultry and limit red meats to a few servings of lean cuts a week for a healthy diet.
Eggs and Dairy
Eggs and dairy are other sources of animal protein, but unlike meat are consumed by lacto-ovo vegetarians who may have ethical or religious concerns about killing animals for food. A large egg contains 6 grams of protein and 70 calories, but as each egg has 185 milligrams of cholesterol, you should limit egg consumption if your health care provider has suggested that you limit dietary cholesterol. One cup of milk supplies 8 grams of protein, and a cup of yogurt, 9 to 12 grams.
Soy products are very good sources of nonanimal protein, containing no cholesterol or saturated fat. A serving of soybeans, tempeh, textured vegetable protein or tofu contains from 11 to 25 grams of protein. Most grocery stores sell soy substitutes for animal products, including soy milk, soy burgers, soy chicken and even soy ice cream.
Beans, Grains and Vegetables
Beans, grains and vegetables are the main protein sources in many cuisines. Even vegans can meet their daily needs for protein from a diet completely without animal products. One cup of lentils, kidney, pinto or black beans contains 12 to 18 grams of protein. Grain-based dishes such as pasta, couscous, rice and bread average 5 to 8 grams of protein. Such vegetables as potatoes, broccoli or mushrooms add 2 to 5 grams a cup of additional protein to your meal.
Fruits can contain between 1/2 gram and 4 grams of protein per cup. One cup of avocado, for example, has 3 grams of protein; one medium tomato has 1 gram of protein, and half of a grapefruit has about 1 gram. Although fruits are not major protein sources, they supply many important vitamins and minerals and substantial amounts of fiber. Although a diet consisting exclusively of fruit would probably be protein deficient, fresh fruits and vegetables should constitute at least half your daily food intake, according to the U.S. Department of Agriculture guidelines.