(What is the best source of protein?)

We love a good old food-related debate here. But we also love taking a scientific approach to any wellness trend or healthcare claim. This time we are adding some fuel to the protein question. While both animal-based and plant-based foods can provide protein, there is a long-standing parley on what is the optimal source of protein: meat or plants?

First things first: protein is an essential nutrient for the human body, serving as a building block for muscles, bones, cartilage, skin, and blood. It is composed of amino acids, which are classified as essential or nonessential based on whether the body can produce them or not.


Meat is a complete source of protein, meaning it contains all of these essential amino acids in the amounts that the body requires. Animal protein is also a source of heme iron, which is more easily absorbed by the body compared to the non-heme iron found in plant sources. Heme iron is important for the body's production of red blood cells, and a deficiency in heme iron can lead to anemia. Animal-based proteins also offer a rich source of vitamins, minerals, and micronutrients like iron, zinc, vitamin B12, and omega-3 fatty acids. However, it is crucial to consider the quality and source of animal protein and make sure you know where your meat comes from and what the animal was fed with.


On the other hand, plant-based protein sources provide a variety of essential vitamins, minerals, and fiber. They are also generally lower in saturated fat and cholesterol than animal sources, which can help reduce the risk of heart disease and other chronic illnesses. While plant-based protein sources may not contain all of the essential amino acids in the same proportions as animal sources, a balanced diet can easily provide the necessary set.

One common misconception is that plant-based proteins are inferior to animal proteins due to their lower protein quality. However, this has been challenged by recent research. A 2019 study published in The American Journal of Clinical Nutrition found that

"plant-based protein can support muscle mass and strength to the same extent as animal-based protein".

Another study published in The Journal of Nutrition in 2020 found that a high-protein plant-based diet can improve body composition and lower cholesterol levels. Moreover, studies also suggest that plant-based protein diets may lower the risk of chronic diseases, including cardiovascular conditions, obesity, autoimmune diseases and certain types of cancer.

It is important to note that not all plant-based protein sources are equal. Some plant sources, such as soybeans, quinoa, and buckwheat, are considered complete proteins because they contain all of the essential amino acids. Other sources, such as beans, nuts, and grains, can be combined to provide a complete protein profile.


In addition to amino acids and heme iron, the debate on optimal protein sources also extends to the impact on the environment and animal welfare. Animal agriculture is a significant contributor to greenhouse gas emissions and land use, while plant-based diets have been shown to have a lower environmental impact. Additionally, the treatment of animals in the meat industry has been a topic of concern for many consumers.

Ultimately, the debate on optimal protein sources is very personal. Both animal and plant-based sources can provide the necessary protein and nutrients for a healthy diet, and the choice often comes down to your preference, health concerns, and environmental and ethical considerations. At the end of the day, It is important to focus on consuming a varied, whole-food, balanced diet, regardless of the protein source.



  1. Campbell, T.C. and Campbell, T.M., 2006. The China Study: Startling Implications for Diet, Weight Loss and Long-Term Health. BenBella Books.
  2. Craig, W.J., 2009. Health effects of vegan diets. The American Journal of Clinical Nutrition, 89(5), pp.1627S-1633S.
  3. Craig, W.J. and Mangels, A.R., 2009. Position of the American Dietetic Association: vegetarian diets. Journal of the American Dietetic Association, 109(7), pp.1266-1282.
  4. Dinu, M., Abbate, R., Gensini, G.F. and Casini, A., 2017. Vegetarian, vegan diets and multiple health outcomes: a systematic review with meta-analysis of observational studies. Critical Reviews in Food Science and Nutrition, 57(17), pp.3640-3649.
  5. Lippi, G., Cervellin, G. and Mattiuzzi, C., 2016. Meat consumption and cancer risk: a critical review of published meta-analyses. Critical Reviews in Oncology/Hematology, 97, pp.1-14.
  6. Naja, F. and Hwalla, N., 2017. Impact of vegetarianism on food intake, anthropometry, and serum biomarkers of insulin resistance and inflammation. Journal of the American College of Nutrition, 36(4), pp.259-266.
  7. Rizzo, N.S., Sabaté, J., Jaceldo-Siegl, K., Fraser, G.E. and 2013. Vegetarian dietary patterns are associated with a lower risk of metabolic syndrome: the adventist health study 2. Diabetes Care, 36(8), pp.2267-2275.
  8. Tang, G.W.K., 2017. The effectiveness of plant-based diets in reducing the risk of cardiovascular disease. American Journal of Lifestyle Medicine, 11(3), pp.216-227.
  9. Tuso, P.J., Ismail, M.H., Ha, B.P. and Bartolotto, C., 2013. Nutritional update for physicians: plant-based diets. The Permanente Journal, 17(2), pp.61-66.
  10. UN Food and Agriculture Organization (FAO). (2019). The Future of Food and Agriculture–Trends and Challenges. Retrieved from


Image: Serine amino acid by Antonio Romero

Previous post
(Is there a link between hormones and digestion?)
Next post
(Foods to avoid if you have hormonal acne)