REF:
https://www.facebook.com/groups/PNCe...2938314936530/
[Tip of the Day - PROTEIN NEEDS & FAT STORAGE]
There's been a lot of chatter recently about how much protein humans can absorb in a meal, benefit from in a day, eat without dying, etc. As well as some seeming confusion on how the human body actually stores excess calories.
So, my aim today is to clear up some of this confusion, and hopefully help you better help your own clients and patients.
Let's start with the protein needs and usage.
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First, there isn't one known limit of protein intake at a meal whereby extra protein becomes "wasted", "useless" or "stored as fat".
Fact is, the best data we have on protein intake are long-term, chronic-intake studies that determine hard outcomes (e.g. actual muscle gained, fat lost, or health outcomes).
Much of this discussion around a set amount of protein at a given meal is based on acute, short-term studies looking at soft end points (e.g. measures of protein synthesis, protein breakdown, or nitrogen balance).
These are important studies, but acute outcomes don't always translate to chronic outcomes. So, these pathway studies and their ilk must be put in context with what we see in longer-term chronic studies.
And when looking at the combined data, here is what see.
Recently, Alan Aragon and Brad Schoenfeld published a paper reviewing the evidence of protein intake on a per-meal basis as it relates to increasing muscle mass. What they found was the evidence currently states that to maximize musular growth in humans requires about 0.4-0.55g of protein per kg of bodyweight per meal. Assuming about 4 meals per day. Thus providing 1.6-2.2g/kg of total protein intake daily.
(Here's the paper for those interested:
https://jissn.biomedcentral.com/arti...970-018-0215-1)
Of course, this paper was strictly about muscle gain. When it comes to fat loss, protein intake often needs to be even higher (particularly in advanced individuals to maximally retain lean mass). Therefore, per-meal intake would have to be higher, as simply spreading out intake over more meals has it's own tradeoffs.
Examine.com recently had a fantastic write-up looking at protein needs in varying situations for varying folks. Indeed, they show protein needs for active individuals looking to lose body fat at 2.2-3.3g/kg! These intakes would be nearly impossible to achieve with these theoretical 20, 30 or 40g per meal limits.
(To put this into perspective, as an 87kg individual I would need up to 287g of protein daily to maximize lean mass retention while losing body fat. If even 40g was my per-meal limit, this would require me to eat 7 meals per day [which sounds incredibly impractical].)
(Here's Examine's post:
https://examine.com/nutrition/how-mu...ein-do-i-need/)
Yet, let's look at the protein needs of the "average" American adults who are sedentary and looking to lose body fat (according to the literature and Examine post, they need 1.2-1.5g/kg of protein per day).
The average American adult female is just under 170lbs, or 77kg.
The average American adult male is about 196lbs, or 89kg.
This would put their protein needs at 92-116g daily for the woman, and 107-134g daily for the man.
If you divide this by 4 daily meals, that would be 23-29g per meal for the woman, and 27-34g per meal for the man.
In that regard, the commonly cited 30g per meal would actually be a good target for a good chunk of the adult American population.
However, to claim it is some "max" where the rest will be "wasted" is where it truly misses the mark. Beyond also lacking context and not being appropriate for a wider range of individuals.
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To wrap this up I quickly wanted to point a few items on how humans store excess calories.
The idea that excess protein will be converted into fat (mostly) misrepresents what really happens in caloric excess. It can happen under extreme circumstances, but the body would rather not store protein as fat if it has other options (because it is incredibly inefficient). And it almost always had other options.
When in caloric excess the body typically prefers to store excess calories from dietary fat, because it is the most efficient. There's only about a 3% or so caloric loss to do so.
The next option would be carbs, but this also only happens to any significant degree when fat intake is incredibly low (<10% of calories) and/or carb intake is inordinately high (e.g. >700g of carbs daily). This is called de novo lipogenesis, and it typically only makes up a small portion of human fat storage (like 1-2% or so). This is mainly because it is far less efficient to do so, with a 20-30% caloric loss when converting carbs to fats.
When in caloric excess the body much prefers to simply store the excess calories by storing more dietary fat, and oxidizing the dietary carbs and protein.
(Interestingly, having a higher intake of protein does make it harder for the body to store excess calories as fat -
https://jissn.biomedcentral.com/artâ...550-2783-11-19)