Mythbusting Protein!

Yesterday, we asked you for your policy on protein consumption. The distribution of responses was as follows:

• A marginal majority (about 55%) voted for “Protein is very important, but we can eat too much of it”
• A large minority (about 35%) voted for “We need lots of protein; the more, the better!”
• A handful (about 4%) voted for “We should go as light on protein as possible”
• A handful (6%) voted for “If we don’t eat protein, our body will create it from other foods”

So, what does the science say?

If we don’t eat protein, our body will create it from other foods: True or False?

Contingently True on an absurd technicality, but for all practical purposes False.

Our body requires 20 amino acids (the building blocks of protein), 9 of which it can’t synthesize and absolutely must get from food. Normally, we get those amino acids from protein in our diet, and we can also supplement them by buying amino acid supplements.

Specifically, we require (per kg of bodyweight) a daily average of:

1. Histidine: 10 mg
2. Isoleucine: 20 mg
3. Leucine: 39 mg
4. Lysine: 30 mg
5. Methionine: 10.4 mg
6. Phenylalanine*: 25 mg
7. Threonine: 15 mg
8. Tryptophan: 4 mg
9. Valine: 26 mg

*combined with the non-essential amino acid tyrosine

Source: Protein and Amino Acid Requirements In Human Nutrition: WHO Technical Report

However, to get the requisite amino acid amounts, without consuming actual protein, would require gargantuan amounts of supplementation (bearing in mind bioavailability will never be 100%, so you’ll always need to take more than it seems), using supplements that will have been made by breaking down proteins anyway.

So unless you live in a laboratory and have access to endless amounts of all of the required amino acids (you can’t miss even one; you will die), and are willing to do that for the sake of proving a point, then you do really need to eat protein.

Your body cannot, for example, simply break down sugar and use it to make the protein you need.

On another technical note… Do bear in mind that many foods that we don’t necessarily think of as being sources of protein, are sources of protein.

Grains and grain products, for example, all contain protein; we just don’t think of them as that because their macronutritional profile is heavily weighted towards carbohydrates.

For that matter, even celery contains protein. How much, you may ask? Almost none! But if something has DNA, it has protein. Which means all plants and animals (at least in their unrefined forms).

So again, to even try to live without protein would very much require living in a laboratory.

We can eat too much protein: True or False?

True. First on an easy technicality; anything in excess is toxic. Even water, or oxygen. But also, in practical terms, there is such a thing as too much protein. The bar is quite high, though:

❝Based on short-term nitrogen balance studies, the Recommended Dietary Allowance of protein for a healthy adult with minimal physical activity is currently 0.8 g protein per kg bodyweight per day❞

❝To meet the functional needs such as promoting skeletal-muscle protein accretion and physical strength, dietary intake of 1.0, 1.3, and 1.6 g protein per kg bodyweight per day is recommended for individuals with minimal, moderate, and intense physical activity, respectively❞

❝Long-term consumption of protein at 2 g per kg bodyweight per day is safe for healthy adults, and the tolerable upper limit is 3.5 g per kg bodyweight per day for well-adapted subjects❞

❝Chronic high protein intake (>2 g per kg bodyweight per day for adults) may result in digestive, renal, and vascular abnormalities and should be avoided❞

Source: Dietary protein intake and human health

To put this into perspective, if you weigh about 160lbs (about 72kg), this would mean eating more than 144g protein per day, which grabbing a calculator means about 560g of lean beef, or 20oz, or 1¼lb.

If you’re eating quarter-pounder burgers though, that’s not usually so lean, so you’d need to eat more than nine quarter-pounder burgers per day to get too much protein.

High protein intake damages the kidneys: True or False?

True if you have kidney damage already; False if you are healthy. See for example:

• Effects of dietary protein restriction on the progression of advanced renal disease in the modification of diet in renal disease study
• A high protein diet has no harmful effects: a one-year crossover study in healthy male athletes

High protein intake increases cancer risk: True or False?

True or False depending on the source of the protein, so functionally false:

• Eating protein from red meat sources has been associated with higher risk for many cancers
• Eating protein from other sources has been associated with lower risk for many cancers

Source: Red Meat Consumption and Mortality Results From 2 Prospective Cohort Studies

High protein intake increase risk of heart disease: True or False?

True or False depending on the source of the protein, so, functionally false:

• Eating protein from red meat sources has been associated with higher risk of heart disease
• Eating protein from other sources has been associated with lower risk of heart disease

Source: Major Dietary Protein Sources and Risk of Coronary Heart Disease in Women

In summary…

Getting a good amount of good quality protein is important to health.

One can get too much, but one would have to go to extremes to do so.

The source of protein matters:

• Red meat is associated with many health risks, but that’s not necessarily the protein’s fault.
• Getting plenty of protein from (ideally: unprocessed) sources such as poultry, fish, and/or plants, is critical to good health.
• Consuming “whole proteins” (that contain all 9 amino acids that we can’t synthesize) are best.

Learn more: Complete proteins vs. incomplete proteins (explanation and examples)