Protein Needs: Animal Protein vs. Plant Protein

Our protein needs are generally around 10 to 20% of daily energy intake, although individual requirements vary based on age, body size, activity level, and health status. All proteins, whether animal or vegetable, are made up of amino acids. Some amino acids are essential because the body cannot synthesize them in sufficient amounts and must obtain them from food. The nutritional quality of a protein depends on its amino acid profile, digestibility, and ability to provide the essential amino acids the body needs.

For a broader understanding of how protein fits into a balanced diet, see our guide to nutrients in your diet.

Animal Protein vs. Plant Protein

Animal proteins are generally rich in essential amino acids and are often highly digestible. Some animal foods, such as meat and eggs, also provide highly bioavailable forms of nutrients such as iron and vitamin B12. However, the health effects of animal protein depend on the food source and overall dietary pattern. High consumption of processed meats, for example, may be associated with certain health risks.

Vegetable proteins can have lower levels of one or more essential amino acids, depending on the food. Cereals and legumes, for example, have complementary amino acid profiles. Combining a variety of plant foods throughout the day can help provide a broad range of essential amino acids.

Traditional combinations include wheat and chickpeas in North Africa, rice and lentils in India, rice and soy in Japan, rice and red beans in South America, and oats and peas in Europe.

A balanced diet also includes carbohydrates, which are an important source of energy. Learn more about the benefits of carbohydrates and their role in a healthy eating pattern.

Legumes

Legumes—including beans, lentils, split peas, chickpeas, and broad beans—are rich in protein, fiber, B vitamins, and minerals. Depending on the variety, cooked legumes can provide a useful amount of plant-based protein as part of a balanced diet.

Some people experience bloating and gas after eating legumes. Soaking dried beans and lentils before cooking, cooking them thoroughly, introducing them gradually, and chewing food well may help improve digestive comfort.

Vegetable Proteins

Soy

Soy occupies a special place among legumes because it provides a relatively high amount of protein with a useful amino acid profile. Soy foods can also provide healthy fats, fiber, vitamins, and minerals.

Common non-fermented soy foods include soy flour, soy milk, tofu, and soy sprouts. Fermented soy foods include shoyu, tamari, tempeh, miso, and natto. Fermentation can alter the flavor, texture, and digestibility of soy foods.

The Cereals

Choosing whole or minimally processed cereals can provide protein along with fiber, minerals, and B vitamins. Depending on the variety, cereals generally contain around 8 to 10% protein by weight before cooking.

Examples include wheat, spelt, barley, oats, rice, fonio, corn, and millet. Seitan, for example, is a concentrated wheat-gluten protein food.

Cereals can be combined with legumes to create meals with complementary amino acid profiles.

Vegetables and Fruits

Although most vegetables and fruits are not especially high in protein, they contribute important vitamins, minerals, fiber, and other beneficial plant compounds to the diet.

Tubers and root vegetables such as potatoes, yams, Jerusalem artichokes, and cassava can contribute nutrients and energy as part of a balanced meal. Mushrooms also provide small amounts of protein, with the amount varying by variety.

Chestnuts and bananas provide relatively little protein but can contribute carbohydrates, minerals, vitamins, and fiber. Bananas are available as dessert varieties as well as cooking bananas such as plantains.

Risks of Deficiencies

A varied diet can help reduce the risk of nutrient deficiencies. Zinc, for example, is found in animal foods such as eggs, but plant sources include wheat germ, sesame seeds, legumes, and some mushrooms.

Calcium can also be obtained from a variety of foods, including dairy products, calcium-fortified foods, tofu made with calcium salts, and some green leafy vegetables.

Iron deserves particular attention, especially for people following predominantly plant-based diets. Legumes, seeds, nuts, whole grains, and some vegetables contain iron, although plant-based non-heme iron is absorbed differently from the heme iron found in animal foods. Consuming vitamin C-rich foods alongside plant sources of iron can improve non-heme iron absorption. For example, fresh parsley, lemon, or a leafy salad can be paired with a meal containing rice and lentils.

A balanced diet should also consider the quality and quantity of carbohydrates and added sugars. For more information, see our guide to the health effects of white sugar.

Conclusion

Millions of people around the world eat little or no meat, fish, or eggs for economic, health, environmental, cultural, or ethical reasons. Whatever the motivation, plant proteins can be an important part of a nutritious diet.

Legumes, soy foods, whole grains, nuts, seeds, and other plant foods can provide protein while also contributing fiber, vitamins, minerals, and other nutrients. Eating a varied diet is generally more important than relying on a single protein source.

People with specific nutritional needs, medical conditions, pregnancy, or concerns about possible deficiencies may benefit from discussing their diet with a qualified healthcare professional or registered dietitian.