Many people rave about plant proteins or their ability to intake just as much protein as those who eat animal based protein. So what is true, & where is some evidence? Let’s find out!

First, I do want to establish the fact that I understand if you do not eat meat, I am not coming after you. My approaches are evidence based, not merely opinion driven. 

Meat can be consider an important source when it comes to protein intake. This is for a few key reasons:

First, meat or animal based proteins are considered high quality proteins. Meat contains complete proteins, meaning it provides all nine essential amino acids your body can't make on its own. These amino acids are crucial for building and repairing muscles, tissues, enzymes, and hormones.

According to the data in adult vegetarians (depending on the methods and criteria used) indicate that classic vegetarian diets supply more than adequate protein and amino acids. An insufficient protein intake from vegetarian diets may occur if the diet does not include protein-rich foods such as legumes (the most traditional source) and nuts and seeds. https://pmc.ncbi.nlm.nih.gov/articles/PMC6893534/

Animal-derived proteins, such as those found in meat, are considered complete proteins because they contain all nine essential amino acids necessary for human health. In contrast, many plant-based proteins lack one or more essential amino acids. This completeness makes meat a valuable source for meeting amino acid requirements. https://www.verywellhealth.com/complete-vs-incomplete-proteins-11694285?utm_

Meat proteins are highly digestible and have high bioavailability, meaning the body can efficiently absorb and utilize the amino acids they provide. A review in the Journal of Agricultural and Food Chemistry discusses how animal-based proteins generally exhibit higher digestibility compared to plant-based proteins, which can be affected by anti-nutritional factors and processing methods.https://pubs.acs.org/doi/10.1021/acs.jafc.3c00442?utm_

But, according to Day et al. (2022), plant-based foods typically provide less complete protein nutrition because of lower digestibility and source-specific deficiencies in essential amino acids, compared with animal proteins.

https://www.sciencedirect.com/science/article/abs/pii/S0924224421006774

According to a recent article from 2022 titled “The effect of animal versus plant protein on muscle mass, muscle strength, physical performance and sarcopenia in adults: protocol for a systematic review”, 

Proteins from animal food sources are referred to as high-quality proteins due to the presence of all nine essential amino acids (EAA) in high quantities as well as the greater bioavailability of these EAA. In comparison, plant proteins often have very little of one or several of the EAAs, for example many legumes lack methionine, cysteine and tryptophan. They are also less bioavailable due to the structure of plant proteins and high concentration of compounds that bind protein, for example tannins and phytic acid. https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-022-01951-2

Studies have shown that consumption of meat leads to greater muscle protein synthesis compared to plant-based proteins. For instance, a study published in The American Journal of Clinical Nutrition found that minced beef resulted in more rapid digestion and absorption than beef steak, leading to greater postprandial protein retention in older men. https://www.cambridge.org/core/journals/nutrition-research-reviews/article/protein-digestion-and-absorption-the-influence-of-food-processing/450969B0DF46904613ADD5048F73FAC6?utm_

Beyond protein, meat provides essential micronutrients like iron, zinc, and vitamin B12. The "meat factor" refers to the enhancement of non-heme iron absorption from plant-based foods when consumed with meat. A scoping review in The Journal of Nutrition highlights how components in meat can improve the bioavailability of iron and zinc from plant-based meals. https://pmc.ncbi.nlm.nih.gov/articles/PMC9776636/?utm_

For me, I personally rely on meat within my diet as an important source of protein. But, I integrate plants daily. My goals of muscle growth are heavily reliant on proper protein intake, & there is not enough evidence to sway me away from eating more animal based proteins in comparison to plant proteins. But, like I said, my opinion & anecdotal experience.