Plant vs. Animal Protein: Which is Best?
You already understand that protein is important for your health. It supports your muscles, keeps you full after meals, and plays a role in maintaining the tissues in your body. The word protein comes from the word for “primary” in Greek, that’s how incredibly important it is. But, it is a bit confusing to figure out what type of protein is best. Are animal or plant sources optimal for your health?
What is Protein?
Protein is one of three macronutrients where our calories come from. The other two macronutrients are carbohydrates and fat. Protein is made up of building blocks called amino acids. These amino acids link together to make up a large protein molecule.
There are 20 amino acids that are necessary for human health. Of these 20, nine are considered essential amino acids, meaning they must come from the diet. The other 11 are non-essential, as your body can make them on its own. Understanding essential versus non-essential amino acids is important to understand the pros and cons of the different types of high protein food sources.
Pros of Animal Protein
All animal proteins are complete proteins. When a protein is “complete” that means it provides all nine of the essential amino acids we need for optimal health. Eggs, beef, dairy products, poultry, and fish are all excellent sources of all amino acids. This makes it easy to meet your protein needs with little effort.
Animal proteins come with certain essential nutrients such as EPA, DHA, and vitamin B12 that are not found in plant-sources. Animal protein is also a good source of calcium, iron, and zinc which are harder to find and absorb in plant-foods. These are essential nutrients that help keep our brains, bones, and nervous systems healthy.
Cons of Animal Protein
Many animal proteins are high in saturated fat and cholesterol, which has been traditionally believed to increase the risk of heart disease. But, research is not black and white on how saturated fat and cholesterol impact heart disease. In fact, the US Dietary Guidelines released new recommendations that cholesterol does not have to be restricted in the diet because there is no clear link between eating cholesterol and high cholesterol in the blood.1 Additionally, several studies have found that there is no connection between saturated fat intake and heart disease, whereas other studies have found a connection.2,3
Pros of Plant Protein
Plants also contain protein. Plant foods high in protein include beans, nuts, soy, and quinoa. Plants are usually low in saturated fat and contain no cholesterol.
Another benefit of plant-proteins is that they are high in fiber. Fiber has been linked to healthy digestion and may be able to lower cholesterol, reducing risk of heart disease.
Cons of Plant Protein
A con of plant proteins is that most do not contain all nine essential amino acids. Soy is the only exception. But, plant foods can be combined to form a complete protein. For example, beans are low in methionine, but high in lysine. Whereas, rice is high in lysine, but low in methionine. When eaten in combination (it doesn’t even need to be at the same time), they form a complete protein.
Certain plant proteins, such as beans or quinoa, are high in carbohydrates. If you are watching your carbohydrate intake you will need to count them as a protein and starch serving. But, this may not be true for plant-based protein supplements, like IVL’s Plant’ Power Protein which only has 4 grams of carbs per serving.
The Bottom Line about Protein
So, which is best? The answer for most people is probably both, in moderation. Animal protein is highly satiating and provides all the amino acids and many nutrients you need. Plant proteins have little saturated fat, no cholesterol, and are loaded with healthy fiber. Optimally, you should vary your protein sources meal to meal. Not every meal needs to have meat, but you also don’t need to go full vegetarian for optimal health. A combination of animal and plant sources will give you the benefits of both without going overboard.
Yours in health-
Ana Reisdorf, MS, RD
IVL Community Registered Dietitian
- Dietary Guidelines for Americans. Office of Disease Prevention and Health Promotion. https://health.gov/dietaryguidelines/. Updated April 4, 2019. Accessed April 4, 2019.
- Malhotra A, Redberg RF, Meier P. Saturated fat does not clog the arteries: coronary heart disease is a chronic inflammatory condition, the risk of which can be effectively reduced from healthy lifestyle interventions. Br J Sports Med. 2017;51:1111-1112.
- Mozaffarian D, Micha R, Wallace S. Effects on Coronary Heart Disease of Increasing Polyunsaturated Fat in Place of Saturated Fat: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. PLoS Med. 2010;7(3): e1000252.