Nutrition Wars: What is the Best Source of Protein?

Before I start receiving threatening letters, I would like to start this piece by making the following statement: The ethical reasons for being a vegetarian or vegan are noble and only a human with karmic moral autonomy would ever attempt to challenge this truth. And since they’d be arguing the arrogance of human superiority or some such nonsense, they’d be a classifiable wanker.

I’m not writing about morals but about science. Regardless of where our diet falls on the spectrum of meat values (somewhere between cannibalism and those people who only eat fruit that has already fallen off trees), I endeavor to provide information that helps us make healthier choices. So what protein source is “best” for us? Are we supposed to load up on protein shakes and egg whites? How much steak does it take to get a good set of guns? The science of measuring protein quality is complicated. Even scientists agree that the measurements depend on many variables, such as intestinal health, that protein quality is difficult to qualify. To understand why, first we must understand the basics of protein.

Essential versus nonessential: We see these terms often in regard to things like “essential fatty acids,” which our bodies cannot manufacture and therefore must obtain from food sources. How much protein is essential? Most peer-reviewed medical research comes to the same conclusion: Athletes require more protein to support performance than those who are not athletic. Beyond that, there is no consensus. Vegetarian and vegan literature will typically recommend 47 grams or more per day, while the CrossFit coach will recommend 1 gram per pound of body weight. How much we need depends on our individual goals and lifestyle.

Regardless of the goals and lifestyle, however, we should strive to consume quality proteins. Here’s a hint: If it involves industrial meat sources, we are not contributing to our health but rather global warming, colorectal cancer, and extensive evidence of animal cruelty. Before we complain about the inflated price of a pack of grass-fed organic beef, we should review our cable TV bills and consider our priorities.

A compilation of scientific research using various methods of quality measurement, from Protein Efficiency Rate (PER) or the widely accepted though somewhat inaccurate Protein Digestibility Corrected Amino Acid Score (PDCAAS), provides the following order:

  1. Casein and whey isolate: For those of us drinking protein shakes, this is great news. For those of us allergic to milk, we’re not thrilled. While whey isolate removes most lactose, the process of isolating or “denaturing” the proteins also removes some peptides that make the protein so valuable.
  2. Soy: Really. As a protein source, soy has not only a complete amino acid profile, but it gets to tout the unparalleled argument of being a dense source of plant protein that also has lipid-lowering effects. Concerns of frequent and high soy consumption have been raised in recent literature in regard to its content of phytoestrogens (hormone-mimicking compounds) and GMO contamination. As far as absorbable protein goes, however, soy is a high-quality source.
  3. Eggs: While eggs offer complete proteins, many athletes supplementing with egg whites (to achieve protein content but avoid excess calories and fat) will find it hard to get a clean source of egg whites.
  4. Beef: Much like other lean meats, beef scores slightly lower than the perfect 1.0 PDCAAS score of whey, soy, and eggs. It comes in at a .92 for its bio-availability and a high PER (which tells us how well it gets converted into muscle tissue).
  5. Plant protein isolates: We see a lot of these in our protein shakes, and like whey, they are commonly denatured. However, the proliferation of these amino acids in ingredient lists means that most companies are excelling at creating effective, high-quality proteins in shake form. That said, these are not whole foods, and most of your nutritionists will argue that whole foods are always preferred.

Conclusion: Whatever our preferred protein source, we should endeavor to achieve variety while considering the other health benefits or risks when consuming protein. If you are a carnivore who eats a lot of protein, be sure to include some plant sources and don’t bother with industrial processed meats. If you are a vegetarian, get some eggs and dairy in there. And if you are a vegan, don’t live on just soy products. //

Ammi Midstokke lives in Sandpoint, where she raises her daughter on a deeply ingrained fear of gluten and an arguably dangerous appetite for adventure. To read more of Ammi’s writing, visit

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