More protein = more muscles

Taking more protein post workout leads to more protein synthesis

Author

Neil Baugh
January 10, 2024

TLDR: Eating more protein post workout gives your body more to work with even after 25g, debunking a popular myth.

Welcome back to Science Simplified! I’m excited to keep sending out cool studies and looking forward to a good year.

Big Takeaways

  1. There’s a longstanding idea that we can only effectively use ~25g of protein after a workout. Anything more than that becomes waste.

  2. This theory has been used to pitch eating smaller, more frequent meals to space out your protein intake.

  3. This paper disagrees and found that taking up to 100g leads to more protein synthesis and amino acid availability.

How the protein we eat becomes proteins our body can use. Credit: J Trommelen and L van Loon, Cell Medicine, 2023

The Problem

The fitness industry is full of pseudoscience and well-meaning but bad advice. Today, we’ll walk through one example of it that’s had me going for a while now and a recent paper that refutes it.

I’ve always heard that we can only effectively use ~25g of protein at a time post-workout. The idea is that any extra protein is broken down and becomes waste. Meaning, eating/drinking more than that won’t provide any benefit and is basically just wasting food.

When you think about it, this doesn’t make a ton of sense from a common sense perspective. What about all the random animals that eat huge meals then wait obnoxiously long times before eating again? What about all the intermittent fasting people who’ve popped up in the last few years?

Despite it not making sense, I truly believed there was a 25g protein limit for a long time. It’s something I read/heard when I started working out and have just held onto it since then. It’s hard to change your mind on things you’ve believed for a long time, even if it’s random info gained on equally random blog sites as a teenager.

The Solution

This week’s scientists wanted to Myth-Buster the 25g rule and did so by simply comparing what happened after people took either 25 or 100g of protein post-workout.

They produced milk-derived proteins that they could track through the body as they were digested. This let them see if the proteins were degraded, available in the blood, or incorporated into muscle over time.

To test if taking in more protein made a difference, they had people workout and then gave them either 0, 25, or 100g of protein and measured what happened to the proteins over the next 12 hours.

The protein we eat is broken down into its amino acid building blocks and then used to make new proteins by our bodies. Unsurprisingly, the people that drank more protein had higher amino acid concentrations for the entire 12 hour study.

The amount of consumed amino acids that are incorporated into muscle.
Credit: J Trommelen and L van Loon, Cell Medicine, 2023

The 100g protein group incorporated more of the amino acids into their skeletal muscle than the 25g group by a wide margin (the filled circles above). This shows that the more protein you consume, the more your body is able to use.

They also show that taking more protein leads to a small increase in protein degradation, but not enough to outweigh the benefits. They go through a detailed analysis of amino acid profiles, gene expression, and metabolic pathways if you’re interested.

To sum it all up, consuming more protein post workout results in more amino acids available for your body to use, at least up to 100g. Looks like I’m going to start drinking massive protein shakes again, throwback to the highschool days.

The lead scientist on this project apparently doesn’t think it’ll make a difference but never let too much thinking get in the way of your gains!!!

Here’s a post by the lead author going through the paper. I love when scientists break down their work like this and have found a lot of great papers this way (including this one).

See you next week for more science,

Neil

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