Protein is an essential macronutrient, however, the RDA for protein is a lot lower than people think. It’s only 0.8g per kg and even that has been considered to be higher than needed. For an average male, the RDA for protein is about 56g of protein and for average female, it is about 46g.
The meta-analysis looking into the protein requirements of athletes looking to gain muscle mass has found a range of 1.0-1.6g per kg lean body weight. There hasn’t been much benefit found for gaining muscle mass past 1.6g per kg mark.
In North America, people are getting 2-3 times the RDA for protein. Even vegans who don’t eat animal products have been shown to be getting way more protein than needed. High protein diets have been associated with many health problems, which I’ll touch on in future posts. What I want to point out right now is the fact that:
We don’t need as much protein as people think.
The only people benefiting from high protein diets are the ones selling high protein foods (meat and dairy industry and protein supplement companies).
Source of protein also matters. Animal protein sources tend to be high in saturated fats and have dietary cholesterol, heme-iron (highly inflammatory) and L-Carnitine (which converts to TMAO in your body), while having no fiber. Plant-based protein comes as a package packed along with fiber, vitamins, minerals, antioxidants and phytochemicals while being devoid of cholesterol and very low in saturated fat. Furthermore, animal protein itself also increases risk for insulin resistance, ageing, and IGF-1 stimulation which can induce cancer growth, and increases higher acidic load to your kidneys due to different amino acid profile compared to plant protein.
High animal protein has been found to be positively associated with cardiovascular mortality. Whereas, plant protein intake has been found to be inversely associated with all-cause and cardiovascular mortality. Substitution of plant protein for animal protein has been found to be associated with lower mortality, suggesting the importance of protein source.
Plant-based protein sources include:
Legumes (Beans, lentils, chickpeas, tofu, tempeh, peanut butter, etc.)
Whole grains (Quinoa, brown rice, millet, barley, buckwheat, etc.)
Nuts and seeds
Even vegetables have protein in varying levels
Robert W Morton et al. A Systematic Review, Meta-Analysis and Meta-Regression of the Effect of Protein Supplementation on Resistance Training-Induced Gains in Muscle Mass and Strength in Healthy Adults. Br J Sports Med. 2018 Mar; 52(6):376-384.
Song M, Fung TT, Hu FB, Willett WC, Longo VD, Chan AT, Giovannucci EL. Association of Animal and Plant Protein Intake With All-Cause and Cause-Specific Mortality. JAMA Intern Med. 2016 Oct 1;176(10):1453-1463.
Huang J, Liao LM, Weinstein SJ, Sinha R, Graubard BI, Albanes D. Association Between Plant and Animal Protein Intake and Overall and Cause-Specific Mortality. JAMA Intern Med. 2020 Sep 1;180(9):1173-1184.