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The scoop on protein

Introduction

So, there’s a lot of confusion and food fear mongering among protein sources (like all foods). “Meat is unhealthy!” “Too much protein is bad for your kidneys!” “You can’t get enough protein to build muscle from a vegan diet!” Bro, what?! Is all this true? Well, I’ll sort out a few topics for you here! What it is, how much you need, can vegans/vegetarians achieve adequate protein and some great lean sources!

Quick review: What is protein?

Hey! No disrespect, I know you know what protein is but let’s quickly review it:

  • Proteins are essential molecules or nutrients for life; they are large complex molecules found in the cells of all living things.
  • The first thing that might pop up in your head when it comes to the necessity for protein by humans might be muscle mass, but they go wayyyyyy beyond that; they are of critical importance for the structure of ALL tissues in the body.
  • They have an important function in metabolism, immunity, fluid balance, and nutrient transport.
  • Proteins are made up of amino acids.
  • 9 essential amino acids MUST be gotten from the diet (the body cannot produce them). This is 9 out of 20 known amino acids of which the body can produce the other 11 from the essential 9.


What makes a protein source “good”?

What the hell is good protein anyway? First of all, I don’t even like using moral terms when describing food. Why? Context and nuance. What is good for you may not be good for another, and vice-versa. That said, some people may be mistaken about what’s good for them. For example, I had a client who thought beans, rice, and peanut butter were “good” protein sources. Hey, they were right! But not when you’re aiming for 180g of protein a day on 2400 calories and those are your only 3 sources. You’ll likely overshoot your calories and nauseate yourself with peanut butter before you hit your target. So, what would be good for him in this case? He wasn’t vegan but he also wasn’t a huge meat eater so he opted for whey and tofu.

“Good” protein

The more appropriate term for labeling proteins would be complete and incomplete. Incomplete DOES NOT MEAN BAD. I’ll talk on that later for my vegetarian/vegan people (#VeganLife4Eva).

Incomplete (low quality) protein

An incomplete protein is missing one of the 9 essential amino acids in sufficient quantities (e.g. Legumes, nuts, grains & seeds). A diet that lacks any of those 9 essential amino acids in sufficient quantities will preclude (prevent) protein synthesis[*] [†].

Complete protein

Complete proteins have all 9 essential amino acids in sufficient quantities. The best sources would be animal products such as egg whites, meat, poultry, fish, and milk. “No plant sources?” you ask. Soy is the real MVP here (#GoVegans). Popular soy products such as soy milk, tofu, tempeh, miso, and edamame are all complete sources of protein and perfectly vegan/vegetarian friendly. Chances are you’re already getting in enough complete proteins to stay alive. But for muscle gains… We’ll see.

Digestibility
Another important factor in protein quality is digestibility, or how well the body can digest a protein. Protein quality and digestibility can be calculated using a chemical score or PDCAAS but that isn’t practical for everyday diet planning.[‡] Proteins with higher digestibility are more complete. Animal protein sources such as meat and dairy products are highly digestible, as are many soy products; we can absorb more than 90% of these proteins. Legumes are also highly digestible (about 70% to 80%). Grains and many vegetable proteins are less digestible (60% to 90%).4

Something else to consider in protein digestibility is the way it is cooked. For example, egg proteins are 90% digestible when cooked as compared to 50% when eaten raw (yeah, I cringed too, who does that?)1.

What about vegetarians? Can they get high-quality protein?

“We MUST consume meat or dairy products to achieve a complete protein diet…” says the arrogant guy who has probably turned off more women than people turn off YouTube adds (yeah, don’t be that guy 😐).

Remember that one client with the peanut butter, rice, and beans? Beans are low in 2 amino acids (methionine and cysteine) but have adequate amounts of 2 others (isoleucine and lysine). Rice is low in 2 that beans have enough of but contains sufficient amounts of the 2 beans lacks. Couple those bad boys up and you’ve got yourself a banging source of complete protein! Combining protein sources to achieve a complete source of protein is called mutual supplementation (Figure 1 for example) and beans and rice would be called complementary foods.[§] To benefit from mutual supplementation, it would be prudent to eat your complimentary foods during the same day, not necessarily at every meal.4

Figure 1 Complementary food combinations.

How much protein do you need?

The general recommendation by the institute of medicine

The Institute of Medicine has set the recommended daily intake (RDI) for protein at 0.8 grams of protein per kg of body weight per day (0.8 g/kg/d), estimated to cover the requirements of 97.5% of the population. The recommended daily allowance (RDA) for sedentary people matches this recommendation. Within the indicated dosage, no kidney problems have been shown in healthy individuals; however, people with kidney disease should reduce their protein consumption as guided by a clinician.2 These recommendations are thought inadequate for the athletic and geriatric populations for optimal health, but I’m not here to talk about old people.

0.8 g/kg/d? Can you make gains on that!?

In the past, we were ignorant to believe that 0.8 g/kg body weight was enough for everyone to be optimal. Thanks to science, we know that this isn’t the case at all.3 Why do athletes/active individuals need more protein? Well…

  • Regular exercise increases the transport of oxygen to body tissues, requiring changes in the oxygen-carrying capacity of the blood. To carry more oxygen, we need to produce more of the protein that carries oxygen in the blood (i.e., hemoglobin).
  • During intense exercise, we use a small amount of protein directly for energy. We also use protein to make glucose to maintain adequate blood glucose levels and to prevent hypoglycemia (low blood sugar) during exercise.
  • Regular exercise stimulates tissue growth and causes tissue damage, which must be repaired by additional proteins.

Strength athletes (such as bodybuilders and weightlifters) need 1.8 to 2 times more protein than the current RDA, and endurance athletes (such as distance runners and triathletes) need 1.5 to 1.75 times more protein than the current RDA.4

Selected recommendations from ISSN position stand on protein & exercise3

As I said, 0.8 g/kg/d isn’t going to cut it for most athletes. So here are some recommendations by the experts on the research:

  1. For muscle building or maintenance 1.4–2.0 g protein/kg body weight/day (g/kg/d) for most exercising individuals.
    1. New evidence suggests that higher protein intakes (>3.0 g/kg/d) may have positive effects on body composition in resistance-trained individuals (i.e., promote loss of fat mass).
  2. Optimal protein intake per serving for athletes to maximize muscle protein synthesis is 0.25 g of a high-quality protein per kg of body weight, or an absolute dose of 20-40 g.[**]
    1. Independent doses of protein per meal should aim to contain 700–3000 mg of leucine and/or a higher relative leucine content, in addition to a balanced array of the essential amino acids (EAAs).
    1. These protein doses should ideally be evenly distributed, every 3–4 hours, across the day.
  3. Benefits can be derived from pre and post-workout protein intake but individual tolerance would be a likely determinant of the optimal period for protein ingestion as the anabolic effects of protein ingestion are long-lasting (>24 hours).

How much is high protein? And is too much a problem?

The acceptable macronutrient distribution range (AMDR) set by the Institute of Medicine is 10– 35% of total energy intake, intakes that are at the latter spectrum are considered high protein diets.2 And guess what? There’s little evidence that a healthy individual with functioning kidneys has suffered from a high protein diet. Let’s end that stigma. High protein diets may actually have the potential to be beneficial in some ways (it keeps appetite at bay, promotes an increase in lean body mass, anabolic signaling & thermogenesis).5 Further research to confirm all this is necessary, however, I’ve eaten 1.5-2.0 g per lb of protein for months with no issues (doesn’t mean that you should).

What are some high-quality & lean sources of protein?

There is a lot to choose from! Here I’ve listed just a few great lean sources of protein (since the regular versions should already be well known).4

Protein SourceCalories
(kilocalorie;kcal)
Protein (grams;g)Fat (grams;g)Serving
White fleshed fish85–13020-253100-gram
Plain Greek yogurt54101100-gram
Beans, Peas & Lentils1408-121100-gram
White meat (chicken, turkey)165303.5100-gram
Low fat cottage cheese8110.52.3100-gram
Lite Tofu548.31.7100-gram
95% Lean Beef171266.5100-gram
Powdered peanut butter462
42
46.2 511.5 1.5100-gram
2 tbsp
Low-fat milk42
102
3.4 8.21
2.4
100-gram
1 Cup
Pork Loin143263.5100-gram
Shrimp99211100-gram
Egg white48
16
10 3.30 0100-gram
1 Egg (large)
Bison17925.58.6100-gram
Casein Supplement36572.73100-gram
Whey4156210100-gram
Figure 2 Summary of lean protein sources and their approximate nutrient and calorie measures.

That’s it for this blog! Don’t forget to subscribe for updates on future posts!

References

1.         Evenepoel, P. et al. Digestibility of Cooked and Raw Egg Protein in Humans as Assessed by Stable Isotope Techniques. J. Nutr. 128, 1716–1722 (1998).

2.        Phillips, S. M. Dietary protein for athletes: From requirements to metabolic advantage. Appl. Physiol. Nutr. Metab. 31, 647–654 (2006).

3.        Jäger, R. et al. International Society of Sports Nutrition Position Stand: Protein and exercise. J. Int. Soc. Sports Nutr. 14, 1–25 (2017).

4.        L.Thompson, J. & Melinda M.Manore, L. A. V. The science of nutrition. Pearson Education, Inc. (2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings, 2017).

5.        Cuenca-Sánchez, M., Navas-Carrillo, D. & Orenes-Piñero, E. Controversies Surrounding High-Protein Diet Intake: Satiating Effect and Kidney and Bone Health. Adv. Nutr. 6, 260–266 (2015).


[*] The process by which the body makes proteins using amino acids. This occurs in the ribosomes of the cell.

[†] Another limiting factor of protein synthesis is energy (calories), hence the inefficiency of hypocaloric diets for muscle gain.

[‡][‡] The protein digestibility corrected amino acid score (PDCAAS) is what is used to measure protein quality in labs by using the chemical score and a correction factor for digestibility to calculate a value for protein quality. A chemical score can also be used to measure protein quality by a relative measure of the amount of the limiting amino acid in one food to the amount of the same amino acid in another.

[§] Mutual supplementation is the process of combining two or more incomplete protein sources to make a complete protein, and the two foods involved are called complementary foods; these foods provide complementary proteins that, when combined, provide all nine essential amino acids.

[**] They also noted that optimal protein intake per serving for athletes to maximize MPS are ambiguous and depend on age and recent resistance exercise stimuli.

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