How to interpret research part III: Protein

MrRippedZilla

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Today is another example of study design flaws, found in the body of the paper, nullifying the apparent take home message contained in the abstract. Let's begin:


Daytime pattern of post-exercise protein intake affects whole-body protein turnover in resistance-trained males


Full paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3514209/

Abstract:
Background
The pattern of protein intake following exercise may impact whole-body protein turnover and net protein retention. We determined the effects of different protein feeding strategies on protein metabolism in resistance-trained young men.
Methods
Participants were randomly assigned to ingest either 80g of whey protein as 8x10g every 1.5h (PULSE; n=8), 4x20g every 3h (intermediate, INT; n=7), or 2x40g every 6h (BOLUS; n=8) after an acute bout of bilateral knee extension exercise (4x10 repetitions at 80% maximal strength). Whole-body protein turnover (Q), synthesis (S), breakdown (B), and net balance (NB) were measured throughout 12h of recovery by a bolus ingestion of [15N]glycine with urinary [15N]ammonia enrichment as the collected end-product.
Results
PULSE Q rates were greater than BOLUS (~19%, P<0.05) with a trend towards being greater than INT (~9%, P=0.08). Rates of S were 32% and 19% greater and rates of B were 51% and 57% greater for PULSE as compared to INT and BOLUS, respectively (P<0.05), with no difference between INT and BOLUS. There were no statistical differences in NB between groups (P=0.23); however, magnitude-based inferential statistics revealed likely small (mean effect±90%CI; 0.59±0.87) and moderate (0.80±0.91) increases in NB for PULSE and INT compared to BOLUS and possible small increase (0.42±1.00) for INT vs. PULSE.
Conclusion
We conclude that the pattern of ingested protein, and not only the total daily amount, can impact whole-body protein metabolism. Individuals aiming to maximize NB would likely benefit from repeated ingestion of moderate amounts of protein (~20g) at regular intervals (~3h) throughout the day.


What the abstract is suggesting...

Consuming 20g of protein every 3 hours is the best way to maximize protein balance, and therefore long term gains, in experienced lifters.


What you'd know only if you read the full paper...

We do indeed have trained lifters (described as participating in high intensity training 4-6xweek) to eliminate the newbie effect and the diet was standardized for 3 days prior to testing. That's where the good stuff ends, its a methodological shit show from this point forward.

This study only assessed markers 12hrs post-wo
This means you cannot apply its findings to the long term because, as we have seen repeatedly, acute effects do not translate to long term effects when it comes to muscle hypertrophy (here you'll find an excellent example of this).

They only used 80g of protein, which amounts to about 0.9g/kg.
So not only to the results apply only to an acute setting (meaningless in reality), they also only apply in the face of sub-optimal protein intake (meaningless for most trainees).
I am convinced that the authors purposely chose such a low dose because they knew damn well that protein frequency becomes more important in the face of a sub-optimal intake. In other words, it would be easier for the results to be "significant" and give them as authors some brownie points. Why do I say this? Easy answer.
In the introduction to the paper, within the first sentence in fact, the authors referenced 2 papers that stated the protein needs of experienced trainees to be 1.2-1.7g/kg (here) or 1.8-2.7g/kg (this paper was actually authored by Stuart Phillips, one of the authors of the current study too!) - goes to show that they knew damn well that the protein intake was going to be sub-optimal going in.
There is absolutely no justification for such a massive difference in protein intake (33-300% less than what it should be) unless the authors did not intend for the results to have any real life relevance (mental masturbation only). In which case, they shouldn't be making bold, bullshit, conclusions in the ****ing abstract. Is this an example of bias in order to achieve a particular outcome? Yes, yes it is.

They used nitrogen-flux to measure protein balance, which is a very rough estimate to say the least.
Nitrogen-flux isn't capable of distinguishing between nitrogen turnover in muscle vs other tissues. I find it amusing that the authors accept this limitation by stating that "A limitation of whole-body tracer methodologies is the inability to delineate tissue-specific changes in protein metabolism" and yet aren't willing to admit their bias when it comes to the bullshit protein intake.

Finally, they only gave whey protein for 12hrs post-wo, further nullify the relevance of the results.
I'm not aware of anyone who only consumes whey protein post workout and nor should you since, IMO, a mixed meal would've made the small differences between the conditions in this study even smaller. This is important since the small differences they did find when it came to protein balance weren't significant to begin with.


Summary

This study is not evidence for consuming 20g of protein every 3 hours, despite the fact that MANY abstract readers have taken it to be just that.
Assuming your awake for 16hrs of the day, this study will likely have you consume a sub-optimal amount of protein since we're talking maybe 100-120g every day as a max. And when it comes to what matters for gains, overall protein intake beats protein frequency every single time.

If your an experienced trainee consuming an adequate amount of protein per day, you won't see much of a difference between 3 vs 6 meals per day so don't worry too much about it.

Finally, another lesson in not relying on the abstract for the full story. Get your hands on the full paper, I'll help where I can, and be able to interpret the results within the relevant, or in this case irrelevant, context :)
 
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Gibsonator

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I would shrivel up to nothing taking in 120 g protein/day. nice write up bro
 

MrRippedZilla

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In before you can only process xx amount of grams of protein in one sitting and all hell breaks loose.

I'll probably need to address that nonsense at some point too. TL;DR - evolution did not design us to be protein wasting machines.
 

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