Choosing between animal and plant protein sources depends on several factors, including your individual nutrition goals, dietary preferences, and the cultural or ethical values that shape your eating habits.
Understanding the differences between these protein sources, including their nutritional benefits and potential drawbacks, can help you make informed choices that align with both your health objectives and lifestyle preferences.
Nutritional Value
Animal and plant protein sources are both nutritious.
Animal Protein
Animal protein sources contain nutrients that are either less available or not available in plant sources. This includes having a full complement of essential amino acids for muscle growth and development.1 A term used for this is complete protein, although this may be an outdated concept.2
Animal protein sources also provide zinc, iron, vitamin B12, selenium, and phosphorus.3 Some vitamins and minerals, such as iron, zinc, vitamin A, and vitamin D, are easier for the body to absorb and use when they are obtained from animal protein sources.3
Animal protein is also considered nutrient-dense, meaning it contains a high level of vitamins and minerals per number of calories.4
However, not all animal sources of protein are nutrient-dense. Highly processed meats, such as hot dogs, bacon, and deli meat, may be high in fat, sodium, nitrates, and nitrites. These meats are associated with worse health outcomes, such as obesity, heart disease, diabetes, and certain cancers.4
Plant Protein
Plant protein sources also contain important nutrients, but you would have to consume much more of these foods than animal products to get the same amount of protein. For instance, some plant sources contain calcium, but it may be difficult to eat enough of these foods to get the recommended amount of calcium.4
Dietary fiber is found in plants but not animals. Its health benefits include:5
- Improved gut health
- Prevention and treatment of constipation
- Protection against the development of colon and rectal cancer
- Reduced risk of heart disease
- Reduced risk of mortality
- Supporting metabolic health (including insulin sensitivity)
Plant protein sources also have the benefit of being lower in saturated fat than animal sources.65
Digestibility
Several factors affect the digestibility of food, including:
- How it’s processed
- How it’s stored
- How it’s cooked
However, animal protein sources are generally more digestible than plant protein sources.3 Meat, fish, cheese, and milk are considered highly digestible.7
Plant protein sources, which also contain fiber, are only partially digested or not digested by the body. Fiber passes through the digestive system, giving stool bulk and making it softer.
Environmental Impact
Animal and plant protein sources have different environmental impacts. While animals are useful food sources, meat production negatively impacts the environment, including water and land resources, more than plant sources.4
Commercial meat substitutes (such as Impossible Burger, Beyond Meat, and Tofurky) may have less environmental impact than animal protein sources.4 However, the use of substitutes has not yet become widespread.
Populations that eat a lot of meat, including the United States, could lower the environmental impact by reducing their meat consumption. Choosing animal proteins produced with more sustainable practices is also a way to lessen the environmental effect of meat protein.4
Potential Concerns
Some animal protein sources may carry risks. These include:1
- Obesity
- Metabolic dysfunction-associated steatotic liver disease (MASLD, formerly known as nonalcoholic fatty liver disease, or NAFLD)
- Type 2 diabetes
Some research shows that replacing 5% of animal protein sources with plant protein over 15 years decreases the risk of type 2 diabetes.
Guidelines for Saturated Fat
The Dietary Guidelines for Americans 2020-2025 (DGA) recommends limiting saturated fat intake to less than 10% of daily calories.
Reducing animal protein sources in the diet and replacing them with plant-based proteins might lower the risk of those outlined above.1
A vegan eating plan, which doesn’t include animal protein, might increase the risk of deficiency in:9
- Vitamin B12
- Zinc
- Iron
Which Is Better for Weight Loss?
Studies have shown that high-protein diets, in general, are helpful for weight loss.1
No matter where the protein comes from—animal or plant—a high-protein diet can produce satiety (a satisfied feeling of fullness) since some proteins are slow to digest.
Overall, there is a lack of research comparing the effects of animal vs. plant proteins on weight loss.1
Rich Protein Sources
For people looking to increase their protein intake, a variety of foods can be chosen.
Animal sources of protein include:
- Beef
- Chicken
- Cottage cheese
- Eggs
- Greek yogurt
- Milk
- Salmon
- Shellfish (clams, oysters, scallops, shrimp)
- Soy (soy milk, tempeh, tofu)
- Tuna
- Turkey
Plant sources of protein include:
- Beans (black, cannellini, chickpea, kidney, navy)
- Green peas
- Nuts and nut butter (almond, peanut, walnut)
- Oats and oatmeal
- Quinoa
- Seeds (chia, hemp, pumpkin, sesame, sunflower)
Summary
Protein is essential to human health and may come from animal or plant sources. Choosing which ones to prioritize in an eating plan is a matter of personal choice and availability. Long-term health outcomes may also be affected by protein choices. More studies are needed to understand the differences between animal and plant proteins and how they affect individuals.
Tresca is a writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16
9 Sources
-
Anjom-Shoae J, Feinle-Bisset C, Horowitz M. Impacts of dietary animal and plant protein on weight and glycemic control in health, obesity and type 2 diabetes: friend or foe? Front Endocrinol (Lausanne). 2024;15:1412182. doi:10.3389/fendo.2024.1412182
-
Mariotti F, Gardner CD. Dietary protein and amino acids in vegetarian diets—a review. Nutrients. 2019;11(11):2661. doi:10.3390/nu11112661
-
Sheffield S, Fiorotto ML, Davis TA. Nutritional importance of animal-sourced foods in a healthy diet. Front Nutr. 2024;11:1424912. doi:10.3389/fnut.2024.1424912
-
Beal T, Gardner CD, Herrero M, et al. Friend or foe? The role of animal-source foods in healthy and environmentally sustainable diets. J Nutr. 2023;153(2):409-425. doi:10.1016/j.tjnut.2022.10.016
-
Barber TM, Kabisch S, Pfeiffer AFH, Weickert MO. The health benefits of dietary fibre. Nutrients. 2020;12(10):3209. doi:10.3390/nu12103209
-
Hertzler SR, Lieblein-Boff JC, Weiler M, Allgeier C. Plant proteins: assessing their nutritional quality and effects on health and physical function. Nutrients. 2020;12(12):3704. doi:10.3390/nu12123704
-
Ajomiwe N, Boland M, Phongthai S, et al. Protein nutrition: understanding structure, digestibility, and bioavailability for optimal health. Foods. 2024;13(11):1771. doi:10.3390/foods13111771
-
U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition. December 2020.
-
Ferrari L, Panaite SA, Bertazzo A, Visioli F. Animal- and plant-based protein sources: a scoping review of human health outcomes and environmental impact. Nutrients. 2022;14(23):5115. doi:10.3390/nu14235115
