Ranking Proteins

Getting people to eat protein (in general) is a win, and often a hard-won battle.

There are still many lingering fears from the 90s low-fat era that protein, because it contains fat, is going to give you heart disease and hurt your kidneys. The notion of not being able to absorb more than 30g protein in a sitting usually gets thrown in the mix too.  But we often don't know why we believe some of the nutrition lore we repeat; perhaps it makes logical sense to us or our doctor threw out a suggestion about eating less red meat.

Whatever the case, once people start incorporating more protein in their diet, most of the time the results are positive.  They report feeling fuller, more satiated, recovering quicker and feeling energized. Most of us don't rely on rib-eye and schnitzel to meet our protien needs, so most of the practical options end up being perfectly fine in terms of calories, fat and cholesterol content. Chicken breast, cottage cheese, pork loin, protein shakes are all quite lean and low in saturated fat.  So the addition of a few whole eggs, lean steak or chicken thighs is not a cause for alarm. Naturally there are hyperresponders to dietary cholesterol but that can be found out through regular bloodwork.  For most of us, making sensible protein choices, we're just fine.

With some common sense and practicality applied, a wide range of protein options exist for even the most finicky eaters.

Methods of Rank

There are a few different methods used to rank protein, in terms of how it contributes to our absorption and tissue growth. 

Protein Efficiency Ratio is a measurement that is based on feeding rats a test protein and seeing how well it contributes to their growth.  Obviously this one has limitations in terms of it's practicality for humans. 

Bilogical Value is used to determine how much nitrogen from a protein is actually contributing to tissue growth. Better proteins have better protein absorption/utilization and higher amino acid rates.  This has limitations because amino acid absorption is not linear and interactions with other foods would impact the results practically. However it does lend itself to generally doing a good job of ranking essential amino acid content.

Net Protein Utilization is similar to Biological Value but it correlates to protein absorption and not utilization.

Protein Digestibility Corrected Amino Acid Score is newer measure of utilization or absorption.   Out of all the amino acids contained within a protein, this score measures the first limiting amino acid as a percentage of a scientific reference (essentially an agreed-upon ideal for children). This percentage is then corrected by testing the actual protein content in fecal matter to find true absorption.

Protein Solutions

Since the above methods give us good scientific data to rank proteins from ideal to less ideal, they can direct our decision as to which proteins are our staples and which we have occasionally.  Perhaps as simple as ranking animal proteins above soy in terms of quality or choosing which snacks to rely on when you miss a meal are the kinds of suggestions that help the most people.  Eventually though, protein sources have to be considered if someone is after improving their body composition. And there is always the "one guy" who hears protein is better and starts getting triple pepperoni on his pizza. We're probably not going to get ripped on whole milk and brisket so for body-comp focused proteins, I constructed the following cart.

What it measures

This chart measures how much protein is contained within 4 cooked ounces of each source, the energy-density (calorie content) of that 4 ounces and where it ranks on amino acid score and Fullness Factor. Fullness Factor is a term used by Nutrition Data pulled from the current satiety data and focusing on ranking satiety by nutrient content, rather than calorie density.  One practical reason for this is that not all calorie-dense foods are filling, so the actual post-meal satiety is important in ranking how effectively someone feels "full". Fullness Factor compares equal calorie amounts of varying foods compared to a reference food (white bread).

Personally, I prefer people to see that a variety of proteins can make up a quality diet but if we are after calorie-control and satiety that some proteins fare better than others.  

One of the first things to scan for is protein content for 4 ounces. Poultry and beef seem to be the stand-out winners but there are leaner choices with poultry. If you are after the most satiating choices then this correlates very well to the sources with the most protein and fewer calories per serving. This is partially due to be abing to eat larger food volume for the same 4 ounces as well as the satiating effects of insulin stimulated by protein. One very overlooked star on here is cod (or any white fish).  While it may not have as much protein in 4 ounces as chicken or bottom round, it is very low energy density which means you can eat MORE of that food for the same calories as another.  Which sounds more filling, 8 ounces of cod or 3 ounces of brisket?

The amino acid score is measuring how many amino acids come up low for each source.  Beef has more amino acids coming up low than say, eggs or pork. While this isn't a concern because most of us are consuming multiple sources of protein, it certainly helps highlight which ones give us the most bang for our buck, which I have underlined.

Not surprisingly, the highest ranking sources on this table are leaner and less energy-dense.  Even if you aren't solely focused on lowering cholesterol or saturated fats, simply prioritizing sources by protein content, satiety or amino acid score still direct you to many of the same foods.

Maybe this is all a complicated way of saying that full-fat dairy, fatty cuts of meat and slabs of bacon shouldn't be making up the bulk of your protein sources. But you already knew that!