Christopher Gardner Profile picture
Stanford Nutrition Scientist since 1993. Human nutrition. Food systems. Stealth nutrition. Father of 4 boys. Husband of @DrMichelsonPhD

Mar 27, 2022, 13 tweets

PROTEIN MATH GAME

I believe most people who have access to a reasonably diverse diet get ⬆️⬆️ protein than the RDA, especially athletes.

Do you?

Simple math

How much do you weigh?
Doubly-labeled water
% Protein in diet

@mackinprof – please check my math

Wanna play?

Let's start with the % of protein in your diet.
Do you have any idea what that might be?
You don't need to know to play.
If you know great,
If not, have some fun and guess.

Yesterday @ScepticalDoctor provided screen shot below (source?)
Meat eaters ~16%
Vegetarians ~13%
Vegans ~12.5%

@MrBigNoodle noted this:
pubmed.ncbi.nlm.nih.gov/23988511/
with higher amounts (although, in grams).

I find few examples in published lit. of ave’s outside the 15-20% range

Next, please estimate what you to believe your daily caloric intake to be....
....in terms of percent of energy or calories

In the field of nutrition, it is well known that study participants tend to under-report their caloric intake.
Ask @KevinH_PhD

Gold standard for assessing this is doubly-labeled water.

See below for what are considered actual energy intakes for adults maintaining their weight

In general, I assume the ave adult consumes ~2,500 kcal day (< for women, > for men), & gets ~16% protein.

16% of 2,500 kcal is 100 g protein, or ~double the RDA

And now I'm broadening to include athletes who focus more on protein, and eat ⬆️ calories.

Find yourself below.

Now let's add in weight.
Obviously larger people eat more calories and have higher total needs.

I got that for you. Try to find yourself below.

Now, who is below the RDA in this map?

The only cell below the RDA is the 225 lb person who only gets 75g protein/day.

75 g protein X 4 Kcal/g = 300 Kcal

That would be
10% protein in a 3,000 Kcal day
12% protein for 2,500 Kcal
15% protein for 2,000 Kcal

I assume very few 225lb people get <75g protein/day

The only group getting "just" the RDA are those weighing in at 200 lbs who "only" eat 75 g.

That person would have to be eating less than 2,000 kcal/day & maintaining their weight, or getting <15% protein in their diet, to be below 75 g protein.

I'm skeptical that can be done.

Let's move on to the athletes. I believe one of the recommendations for athletes is 1.2-1.6 g/day.

Here are the cells achieving that range (green).
This would be without supplements, and without protein bars and shakes, just food.

And beyond....

I'll call on @mackinprof for guidance on concerns for protein intakes >2.0 g/kg/day. I believe there are some data suggesting reason for concern about impaired performance above this level. Correct?

Here they are, in gray. I would suggest this is easy to achieve.

Example of elite/extreme athletes, caloric intake, & protein intake.

@TRotto53 was the TA for my Human Nutrition class at Stanford back in 2015 and 2016. He was also on the Stanford football team that went to the Rose Bowl in 2016.

At that Kcal level, easy to go >2.0 g/kg/day

Back to @ScepticalDoctor & vegans.

Let's say they only get 12.5% protein (I assume higher, but let's go with that).

& they are maintaining weight, at least 2,000 kcal (doubly-labeled water)

2,000 X 12.5% = 62.5 g protein

~150 lbs (68 kg)

=0.92 g/kg
>RDA
>>EAR

Protein math

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