Ok, so this series got a little out of control; what can I tell you, I have a lot to say on the topic of dietary protein as a function of having written The Protein Book.
I’ve covered a lot of information ranging from the somewhat technical/theoretical (speed of digestion) to very practical (micro-nutrient content, fatty acid content) in an attempt to answer the question what are good sources of protein?
In this final part, I want to cover a few other issues that go into answering that question (that didn’t require a full-blown article of their own) and then I’ll finish by presenting a summary table where I’ll attempt to put everything from this entire series into a comparable perspective.
In What Are Good Sources of Protein – Introduction, I included a short list of other important factors such as effects on appetite and blood sugar that I already addressed in previous parts of this series so I won’t touch on them here. The issues I do want to touch on are availability, the actual protein content, and cost.
It should be obvious that whether or not a given protein source is good or not doesn’t matter if someone can’t get it. The ease of availability of a given protein in a given location is clearly an issue but not one I can speak to except in the most general of terms. What I have access to in the US has no bearing on what someone overseas can or cannot get; in fact I’m quite sure I’ve left out certain whole food protein sources simply due to being located in the US. What someone might have access to in Norway might not be available here and vice versa.
This may seem like an odd category in a series about protein but the simple fact is that all food containing protein don’t only contain protein. As discussed in What Are Good Sources of Protein – Dietary Fat Content, I made it clear that many ‘protein foods’ can contain a significant amount of dietary fat although this can vary massively. In a related fashion, some protein sources also contain carbohydrates. Depending on the goal of course, finding sources that contain a lot of protein compared to their total caloric intake may be one variable that goes into the question of what are good sources of protein.
Basically, what I’m talking about here is how much protein a given whole food provides relative to either the serving size or the total caloric content of that food. If a food provides an enormous amount of protein without providing excessive calories,that food has a high protein content; if it doesn’t, it has a low protein content.
Obviously, this is relevant from a caloric intake standpoint; a protein food containing a lot of carbohydrate and/or fat will have more calories than one that doesn’t. While studies are repeatedly finding that high-protein diets have many benefits, if trying to raise protein content leads to increased caloric intake, that’s not necessarily a good thing.
Looking at specific diets, many ‘high-protein’ diets are also meant to be low in carbohydrates. This means selecting protein sources that don’t contain too many tag along carbohydrate sources or the protein source itself ruins the diet. Similarly, athletes on high-protein but low-fat diets need to choose protein sources without a lot of tag along fats in them. You get the idea.
Now, protein sources based on meat (beef, chicken, pork, fish, eggs) contain, at most, trace amounts of carbohydrates. The exception might be if you ate them fresh after a kill (before the muscle glycogen degrades) but I doubt that describes many people. Individuals trying to raise protein while limiting carbohydrates tend to focus on such foods for that reason.
As discussed in What Are Good Sources of Protein – Dietary Fat Content, the fat content of such foods can vary massively from nearly none (skinless chicken breast) to very high (fatty red meat) and that can be a consideration depending on the situation.
I’d note that, typically, meat protein will contain about 7 grams of protein per ounce. So a 3 oz piece of meat (about the size of a deck of cards) will generally have about 21-24 grams of dietary protein. The protein content of other foods depends on the food.
Dairy products generally always contain some carbohydrates although the amounts can vary. A typical 8 oz. serving of dairy will typically contain about 12 grams of carbohydrates. Cheese is an exception and is typically much lower in carbohydrate containing only small amounts. As noted in the last article, the fat content of dairy can vary significantly from essentially zero in fat-free dairy to moderate levels in full-fat foods.
Beans and nuts, for their caloric content, tend to be lower in terms of protein content due to the presence of tag-along carbs or fats; it’s also nearly impossible to find such foods that don’t have the other macro-nutrients. Beans generally contain a good bit of carbohydrate (along with a chunk of fiber), nuts contain a good bit of dietary fat. That is to say, while many animal based foods can provide essentially pure protein (with no carbs or fats), vegetable source proteins rarely can do this.
Vegetarians or individuals who obtain a lot of protein from vegetable sources who are trying to increase their protein intake via these foods invariably end up getting a lot of ‘extra’ calories from the other macros. This makes following high-protein/low-carb diets with such foods nearly impossible.
Typically, protein powders provide nearly pure protein with only trace carbs. And with the exception of the whole-egg protein powder I mentioned in the last article, few contain more than a gram or two of dietary fat under most circumstances. While I generally prefer that diets be based around whole foods (for a variety of reasons), protein powders can provide a very concentrated source of protein for individuals running into problems with other whole food protein sources.
An issue not often appreciated in answering the question of what is a good source of protein is the cost. Now, unfortunately, this is an issue that tends to be nearly impossible for me to address in any useful way because food costs vary massively. What I’m paying in the United States will vary greatly from town to town and I have absolutely no feel or perspective on what someone overseas will pay. Issues of availability, etc. will affect local food prices and I can’t cover this except in general.
What is often useful is to sit down and calculate out the effective cost per gram of protein for a given whole food protein source. Basically, you add up the total protein and divide that by the cost of that food to determine how much you’re paying per gram of protein.
For example, let’s say you can buy an average can of tuna fish (which typically has about 32 grams of protein) for 50 cents. And let’s say you can buy a cup of yogurt (8 grams of protein) for the same 50 cents. Finally, let’s say we can buy a pound of meat (which will contain about 120 grams of protein) for $4.50 (450 cents) per pound. We can compare each:
- Tuna: 50 cents / 32 grams of protein = 1.8 cents per gram of protein.
- Yogurt: 50 cents / 8 grams of protein = 6.25 cents per gram of protein
- Red meat: 450 cents / 120 grams of protein = 3.75 cents per gram
Obviously the tuna fish is the cheapest, the red meat is second and the yogurt is the least cost-effective. Of course, that cost would be weighed against everything else in this series: issues of quality, other nutrients, etc. Even being more expensive, the dairy might be a better choice for someone wanting a mix of casein/whey along with the dairy calcium that seems to improve body composition.
I’d note that, depending on where you are in the world, protein powders are often far less expensive than whole foods. This is especially true in the United States but is often less so in other countries where shipping jacks up the costs of the powders massively. In any case, with a few simple calculations, you can determine the cost effectiveness of various types of protein.
And, Finally, the Wrap-Up
As noted, I’ve covered a tremendous amount of information in this series. Digestibility, Speed of Digestion, Protein Quality, Amino Acid Profile, Micro-nutrient Content and Fatty Acid Content. In this final article, I’ve looked at three additional factors including availability, protein content, and cost. In the chart below, I’m going to try to summarize everything I’ve talked about to provide readers with an overview of all of those topics. For what should be obvious reasons I haven’t included either cost or availability. This should help to finally answer the question What are good sources of protein?
|Food||Protein Content||Digestibility||Speed||Quality||Important AA*||Micro-nutrients||Fat Content||Fatty Acids|
|Beef||High||High||Slow||High||N/A||Iron, Zinc, B12||Variable||N/A|
|Chicken||High||High||Slow||High||N/A||Iron, Zinc, B12||Variable||N/A|
|Fish||High||High||Slow||High||Taurine?||B12||Variable||W-3 fish oils|
|Whole Egg||Moderate||High||Slow||High||N/A||Iron, Zinc, B12
If you eat a lot
|Whey powder||High||High||Fast||High||23-25% BCAA||Calcium||Low||N/A|
|Casein Powder||High||High||Slow||High||20% BCAA||Calcium||Low||N/A|
A couple of comments on the above chart. N/A simply means that there is nothing particularly noteworthy about a given food in a given category. For example, as I discussed in What Are Good Sources of Protein – Amino Acid Profile, the amino acid profile of most foods is more than sufficient to meet human requirements. As noted above, casein and whey are interesting due to their high content of the BCAA; some sources of soy isolates also contain significant amounts of BCAA and glutamine.
I didn’t talk about the phytoestrogen issue regarding soy protein; this is something I’ll address later on the site. I’ll only say now that the issue of phytoestrogen content is more complex than ‘they are good’ or ‘they are bad’. Again, this isn’t the place.
And that wraps it up. I suspect that some readers were hoping for a nice easy list comparing ‘good’ and ‘bad’ protein sources; unfortunately, the real world tends to be a lot more complex than that. Issues of speed of digestion, digestibility, amino acid profile and micro-nutrient content all goes into determining what is a good source of protein under a given context. The best protein for someone on a low-fat diet attempting to deal with high blood cholesterol is not the same best protein for an athlete looking to maximize adaptation to training.
In general, low fat animal products tend to provide the best quality, highest digestibility, and greatest micronutrient content compared to vegetable source foods; I’m clearly a big fan of dairy proteins for reasons outlined throughout this series. Low-fat meats, dairy, etc. all provide excellent sources of high-quality protein.
Vegetable source proteins also have their own benefits, the fats in nuts are excellent, the fiber content of beans is important to protein nutrition; that’s along with being a decent source of quality protein. Nuts seem to blunt appetite and might be useful for individuals involved in active fat loss. In combination with other high quality sources, vegetable source proteins can add both protein and other important nutrients to the diet.
Of course, protein powders have been used extensively in the athletic world and have even become part of the general nutrition and dieting lexicon. Whey and casein tend to be the ones most focused on but soy proteins are high quality and may raise anti-oxidant status in the body; the phytostrogen issue is too detailed to cover here but I will cover that in a later article.
In any case, hopefully in this series, I’ve covered most of the issues of great importance regarding the topic and given readers sufficient information to make protein choices for their own specific contexts. As noted throughout the series, more detailed information can be found in The Protein Book.
And hopefully, once and for all, this series has answered the question What are good sources of protein?