Here’s something I’ve often though about - what is the best protein source? I will be considering a few factors, namely what is good for both your body and your wallet. I’ve determined 63 (yes 63) potential protein sources. For the full list and results, you can view the data in excel or as a pdf
For all the foods listed, I looked them up on the Walmart website (with a few exceptions on Amazon). I then took the following data:
- Total cost ($)
- Total size (g)
- Calories
- Serving size (g)
- Protein (g)
- Fat (g)
- Carbs (g)
- Fiber (g)
With this information, I then calculated:
- Cost per pound ($)
- Calculated calories
- Number of servings
- Protein %
- Fat %
- Carb %
- Cost per g of protein ($)
Note that the calculated calories was determined as (4 * grams of protein) + (9 * grams of fat) + (4 * grams of carbs). In most cases, the calculated calories were very similar to what was reported on the label. However, in the case of higher fiber items (beans), the calories differed quite a bit. For my calculations, I stuck to what was reported on the label.
Protein %, Fat %, and Carb % are simply the percentage of calories in each food that come from each of the 3 main macronutrients. Ideally, they add up to 100, but due to rounding errors on the nutrition label, most of the time it’s either a little bit under or a little bit over.
As I am looking for what is the best lean protein source, the best food will have a high protein %, with low fat % and carb %. That way, you’re getting more protein for your dollar instead of carbs and fat, which can always be added to whatever you eat.
However, this will only get us the cheapest way to get grams of protein, irrespective of other macronutrients and calories. Looking at just price and grams of protein, the best source would seem to be dried pinto beans; however beans are predominantly carbs, with a protein % of only 28%. Yes, they are a good source of plant based protein that you should be eating as a side, but they are not a strong contented as your sole source of protein. You would have to eat a lot of beans (aka calories and carbs) to hit your protein goals, and everyone else will not appreciate your toxic fumes.
Additionally, not all protein is created equally. Some sources (animal source foods like meat, dairy, and fish) are much more bioavailable in the body compared to others (plant source foods like grains, beans, and vegetables). On the other hand, plant source foods tend to be cheaper than animal source foods.
Vital wheat gluten is a very cheap source of protein as well (on a grams of protein basis), but it is absorbed terribly by the body. You can expect to only get about half the grams of protein from wheat from whats reported on the nutrition facts label, as opposed to animal sourced foods.
To combat this, I also noted down the the quality of the protein of each of the listed foods, which you can read about here. Essentially, it’s a measure of how well each protein source is digested, with a score of 1 (or higher) being the best. There are 2 different (but similar scores):
- DIAAS: Digestible Indispensable Amino Acid Score
- PDCAAS: Protein Digestibility Corrected Amino Acid Score
I noted down both values of each food, and simply took the average of them to use for my analysis. Some foods only had a score in 1 category though, which in that case just the 1 score was used.
Sorting by the protein quality, we see that vital wheat gluten ends up at the bottom, meaning it should not be your main protein source. Peanut butter (rip), rice, and beans, quinoa also had low scores.
At the top of the list in protein quality, we see all animal source foods: pork loin, followed closely by dairy products (protein powder, yogurt, cottage cheese), eggs, meats (chicken, beef, and turkey), and fish
However, this measure doesn’t include cost at all, and assumes you have limited money. So let’s combine these results together; what is the cheapest source of protein that is the most easily digestible in the small intestine?
I came up with a protein score, which is simply (Protein % * Cost per g of Protein) / Protein Quality. This is the formula I determined to give us the overall best source of protein. If you can think of a better way to quantify this, please let me know.
Time to tally up the results; let’s start with the bottom five:
- 63: Sweet Potatoes - 0.34
- 62: Fresh String Beans - 0.57
- 61: Canned String Beans - 0.69
- 60: Fresh Spinach - 0.87
- 59: Yellow potatoes - 0.88
Finally, the moment you’ve been waiting for, here are the top five performers:
- 5: Pork Loin - 22.57
- 4: Boneless Skinless Chicken Breast - 28.18
- 3: Unflavored Casein Protein Powder - 28.64
- 2: Unflavored Whey Protein Powder - 30.09
- 1: Canned Tuna - 30.49
Yes, you read that right; canned tuna is the cheapest high quality protein source. I love canned tuna, and have been a big fan of it for a while. It’s so easy to incorportate into just about anything. I most often eat tuna on top of a salad; just crack open a can, drain, and add to your food. It’s a very cheap and easy protein source that’s shelf stable and requires no preparation. It can also be found in every grocery store, and probably bought in bulk.
It should be noted that due to the mercury content of tuna, it is not advised to eat tuna too frequently, especially if you are pregnant. You can read about it from the FDA, Medical News Today, or Healthline, but the general consensus is that light tuna contains less mercury than albacore tuna, and it is totally safe to eat if you don’t consume it every day (I try not to eat tuna more than once a week).
It has been shown that consumption of selenium can help protected against mercury exposure. You can read that research paper on Science Direct, or some high selenium foods on Healthline. Brazil nuts are extremely high in selenium, so maybe just have a couple of those with your tuna. But don’t eat too much because you don’t want to overdose on selenium either lol.