A new study challenges the conventional wisdom of protein consumption

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You’ve probably heard the conventional wisdom: above a certain threshold (often classified as around 25 grams of protein at one time), the body can no longer synthesize any more protein. Thus, protein should be partitioned to optimize muscle protein synthesis. Combine that synthesis limit with some recommendations for relatively high daily protein intakes, especially for aging athletes, and protein intake can feel like a chore. Brush your teeth, walk the dog and consume protein at predictable intervals.

A new study was published Dec. 19 in the journal Cell Reports Medicine, led by Jorn Trommelen challenges conventional wisdom and may disrupt our thinking about protein consumption. The authors summarize the current state of research:

“Dose-response studies have reported that ingestion of 2025 g of protein is sufficient to maximize post-exercise muscle protein synthesis in healthy young adults. Muscle protein synthesis rate does not increase when more protein is consumed. Higher protein intake did not further increase anabolic signaling, and excess amino acids are assumed to be oxidized.” Therefore, at the moment it is recommended to spread the protein intake evenly throughout the day so that each main meal should have no more than 2025 g of protein.

The authors doubted the limits of protein synthesis when considering other species. While this makes sense based on typical food intake patterns in humans, they said it appears to be at odds with the feeding practices of many animal species in the wild, which consume large amounts of food infrequently. They cite snakes that can consume more than 25% of their body mass in a single meal, resulting in prolonged digestion and protein synthesis over 10 days. And only 5% of this protein is directed to the oxidation of amino acids. I personally think that every study should be required to mention snakes.

Their hypothesis focused on the limitations of previous studies, which in their eyes just needed a longer time horizon or higher doses. According to the researchers, previous studies were limited to 45 grams of protein and lasted 6 hours. Maybe 45 grams isn’t enough to get to the bottom of the protein synthesis issue. As we know from snakes, protein synthesis could theoretically remain high for a significantly longer period of time after consumption. From now on, all I want to do is consume massive amounts of snake science.

RELATED: Signs You May Want to Up Your Protein

New protein research methods

To evaluate the hypothesis, the researchers gave participants a complete resistance training session consisting of five minutes of easy cycling followed by four sets of 10 repetitions of the following exercises:

  • leg press machine,
  • leg extension,
  • latin pull down,
  • and a chest press.

This was a tough routine with the first set at 65% of 1 rep max followed by subsequent sets at 80% of 1 rep max until volitional fatigue. Participants received strong verbal encouragement to push through the barrier of fatigue. You haven’t lived before imagining a post-doc yelling YOU ARE A BEAUTIFUL AND STRONG UNICORN to a research participant doing leg presses.

36 beautiful unicorns (all male, so the horn) received three different protein conditions:

  • placebo
  • 25 grams of milk protein
  • 100 grams of milk protein

The milk protein was from a lactating Holstein cow infused with isotopic markers for tracking. This milk was processed into a protein concentrate, all combined with IV amino acid markers. I couldn’t love this study more than I do now.

The researchers collected 13 blood samples over the next 12 hours, as well as four muscle biopsies. If the researcher were to nudge me that often, they would first have to buy me a drink, preferably containing milk protein from an isotope-infused Holstein cow.

RELATED: 6 Signs Your Protein Intake Is Too Low

Scientific research shows that athletes can synthesize more protein

What science says

Here’s the silver lining: the researchers found that “there is no apparent upper limit to the magnitude and duration of the anabolic response to protein ingestion in vivo in humans.” The 100-gram protein condition resulted in better amino acid availability and muscle protein synthesis, about 30% higher over 12 hours than the 25-gram test. The methodological key was the 12-hour sampling window, which allowed the researchers to see longer-term responses. Although anabolic responses were elevated during the first 4 hours (about 20%), the most significant increase was between 4 and 12 hours (about 40%) As the authors said:

These data support our hypothesis that even very large amounts of dietary protein are efficiently utilized to support postprandial tissue anabolism, but require a longer time period for complete protein breakdown and amino acid absorption to be available for incorporation into tissues.

I am deeply offended whenever someone treats data as a plural word. We get it; you have a PhD but i don’t.

The next discovery focused on the oxidation of amino acids. Work on protein metabolism assumes that amino acids have two fates: (1) they are incorporated into tissues (protein synthesis) or (2) they are broken down (oxidation of amino acids, which can be a sign of excess protein). (Amino acids can too to temporarily add a tissue-free amino acid pool that the authors addressed in other calculations.) Amino acid oxidation did not increase disproportionately at higher protein levels.

Rates of amino acid oxidation were negligible relative to the rate of whole body protein synthesis, although the raw numbers were higher with increased protein intake. In this study, amino acid oxidation does not appear to be a storage room for excess protein where the body can forget about it like an old pair of Hokas.

The authors concluded the article with ambitious statements. They said that dietary recommendations for both health and disease typically recommend an equal distribution of daily protein needs among main meals to support muscle anabolism. These recommendations are based entirely on the belief that the muscle protein synthetic response to ingestion of a single protein bolus is maximal and short-lived. The findings support more flexibility in feeding patterns to enhance muscle anabolism.

CAUSES: The science of carbohydrate and protein supplementation to minimize muscle damage

Implications of protein research

I can’t get over how cool this research is. Click on the study and see the numbers. You know how you get spaghetti, and you know it was made with love by a chef who really, really thinks a lot about pasta? That’s how I feel about those numbers.

Let’s wrap this up with one quote that could show the relevance of observations to our daily lives. According to the authors, we specifically show that consuming a single large amount of protein is followed by a prolonged anabolic response, which would eliminate the need to eat another protein-rich meal in close proximity.

Do you find yourself low on protein? Based on this research, maybe you can do what I sometimes suggest to athletes (but I’d only say publicly today): double up on that scoop of protein every now and then and go about your life without worrying so much about protein timing.

RELATED: What Kind of Protein Should Runners Eat?

Or maybe not. There are still many unanswered questions, and this research will face a lot of critical analysis from experts, especially in relation to previous research. I am far from a nutrition expert and may need some important context, facts, implications or criticism. Above all, breakthroughs like this need to be replicated, and we’re not there yet. In addition, there are many unanswered questions.

How does the use of milk protein affect the findings? What if you put 100 grams against different protein doses, like 33-33-33 or 25-25-25-25? What are the compensatory mechanisms for chronic versus acute protein doses? Are the findings different for different ages? What about activity levels? Is this essential for runners or more so for weightlifters? How does this show up in recovery and adaptation? Does gender matter? Sports or nutrition history?

We were probably just starting a new investigation. For now, I just wanted to draw your attention to a really cool study that challenges conventional wisdom. I can’t wait to see what comes next.

David Roche works with runners of all levels through his coaching service, Some work, all play. She co-hosts MD’s Megan Roche Some work, everyone is playing a podcast about running (and more), and they answer exercise questions in a bonus podcast and science newsletter Patreon page starting at $5 per month.


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