Eating a plant-based diet, such as the Mediterranean diet, has been shown to reduce the risk of heart disease, metabolic syndrome, diabetes, certain cancers. In people over the age of 50, eating more plant protein can decrease the risk of frailty while improving mental and physical function.

According to Harvard Health, a plant-based diet doesn't have to exclude meat, fish, or poultry but focuses on foods primarily from plants. This includes not only fruits and vegetables, but also nuts, seeds, oils, whole grains, legumes, and beans.

Experts say we should aim for 0.8 grams of protein per kilogram of body weight. Multiply your weight in pounds by 0.36 to find the amount of daily protein your body requires. If you weigh 150 pounds, you need 54 grams of protein daily, says Everyday Health.

Here are 7 sources of plant-based protein to diversify your options:

• Lentils. Lentils and other legumes such as beans, nuts and seeds, are wonderful sources of protein with about 9 grams per cup. They are also rich in fiber, vitamins, minerals and antioxidant-rich polyphenols that fight cancer and diabetes. Use lentils in soups and salads or combined with rice and veggies for a power-packed bowl.

• Chickpeas. These tasty legumes are also called garbanzo beans and offer 7.5 grams of protein in a half-cup serving. Toast or roast them with a little curry spice for a tasty snack or blend them with plain, non-fat yogurt to make hummus.

• Tofu. Soy is the main ingredient of tofu that has 9 grams of protein for a 3-ounce serving. Since soy contains all nine essential amino acids, it's a wonderful alternative to meat as a protein source. Use tofu in stir-fries along with an assortment of healthy vegetables.

• Nuts. Although all types of nuts offer protein, almonds have the most protein per serving, about 6 grams per serving of 20 almonds. Nuts are also a good source of unsaturated fats which can lower cholesterol levels, says Everyday Health.

• Quinoa. According to Real Simple, quinoa is a source of complete vegetable protein because it contains all essential amino acids, offering 6 grams of protein per quarter-cup serving. Quinoa also contains fewer carbohydrates and more protein in comparison to other grains. Quinoa is high in magnesium, phosphorus, manganese, and folic acid. Use it in salads or as a substitute for rice or pasta.

• Black beans. Economical and healthy beans, including black, kidney or navy beans, offer about 7.5 grams of protein for a half-cup serving. They are also rich in fiber, folate, magnesium, and iron. Add beans to salads, soups, or stews. If you are buying cooked beans in a can, look for the low-sodium varieties.

• Peanut butter. This old lunch box standby has 7 grams of protein in each two-tablespoon serving. Peanut butter does have lots of calories — about 90 per tablespoon – so watch your serving sizes and enjoy it with apple slices or on whole wheat bread with fresh-fruit preserves.