Paradigm Shift in Protein Recommendations? Does Protein Timing Matter?

As you may know, protein has important roles in health and performance.

Optimal protein intake can:

• Enhance muscle retention during calorie deficits and age related muscle loss, repair after activity, building muscle tissue, and support satiety and energy distribution.

• Maintain important lean tissue during fat loss.

• Supports repair, recovery, and adaptation for the athlete.

• Support longevity and reduce age-related muscle loss for older individuals.

So what happened?

Evenly distributing protein intake is commonly advised in sports nutrition practices, as well as for older individuals to mitigate age related muscle loss. A recent study that is gaining attention questions previously held beliefs.

Although the paper itself is highly detailed, the fundamental premise of the study entailed a 12-hour investigation comparing the effects of consuming 0g, 25g, or 100g of milk protein following a 60-minute full-body resistance exercise routine in healthy, untrained men. It is important to highlight that milk protein comprises 80% slow-release casein and 20% whey, which is slower digesting than a whey protein drink.

The primary findings were a dose-dependent increase in protein synthesis without seeing an upper limit in the 12-hour time frame. In addition, amino acids, which protein is made of, had negligible levels of oxidation (used as energy) in the larger dose. The authors' findings show that the magnitude and duration of muscle building are not as restricted as previously thought in humans. Below is an image of circulating amino acids 0g Vs 25g Vs 100g of protein over zero to twelve hours.

Total amino acid circulation over the 12 hours for each group (0g, 25g 100g)

So what does the study show?

While the 25g dose was mainly digested and absorbed after the 6-hour mark, the 100g protein was still being digested at the end of the 12 hours as seen in the image above. The study provides input on the nuances of protien strategies and can help explain why some studies have shown athletes consuming all there protein within a smaller window while also exercising have achieved the same increases in muscle mass than those not following a time restricted protocol.

While we know that how daily protein intake is distributed is much less important than consuming enough overall protein throughout the day in the first place. But that doesn't necessaarily mean protein distribution doesn’t matter at all. Further research is needed to elucidate whether an even distribution of daily protein intake decreases the breakdown of muscle proteins, as well as if even distribution improves health outcomes in older adults, such as ensuring a better preservation of muscle mass and physical function, resulting in a reduced risk of adverse health outcomes and sarcopenia.

Portein distribution assumptions vs reality. (Credit Pic Jorn Trommelen)

Other research on protein distribution

Another recent study (Mallinson et al. 2023) that was published near the same time as the above, compared the post-exercise protein signalling of 15g, 30g, and 60g of whey protein over 24 hours, opting for two resistance training bouts 4 hours apart, which found the 30g dose at all times points maximised muscle protein synthesis. In contradiction to Trommelen study, it found that muscle protein synthesis was maximum with the 30g dose at all time points and 60g did not increase muscle protein synthesis compared to 30g dose.

A large literature review (Hudson et al. 2020) found that an even distribution- typically recommendeof 30g of protein per meal—typically recommended by practitioners —mise protein signalling. Agregaard 2023 also found whole body protein breakdown in healthy elderly individuals was higher in uneven protein distribution (arppoximtely 15% 15% 60%) than compared to an even distribution (approximitely 30% 30% 30%) after about 5 hours and 8 hours, and area under the curve of the post prandial meal at 11 hours. While there were no differences in muscle protein sysnthesis rates.

Lastly, despite the lack of long-term studies, Yasuda et al. (2020) found that over 12 weeks, evenly distributed protein had a larger effect size on lean mass gain (2.5kg increase) compared to skewed protein intake (1.8kg increase; skewed had lower and high doses of protein at varying times of the day).

So what now?

So does protein timing matter? Is the timing of protein consumption important? The recent study has revealed intriguing results, indicating that protein strategies may offer more flexibility than commonly believed. Consuming larger meals less frequently could prove to be an effective approach, especially if it aligns better with our daily routines. While the overall intake of protein remains crucial, I advise active individuals and older adults to consume protein at least 3–4 times a day, with intervals of approximately 3–5 hours between each meal, aiming for 0.4–0.6 grams of protein per kilogram of body weight (adjusting based on activity levels for those who are physically active) to optimise their dietary strategies.

It's a well designed, highly detailed study, and raises great questions that need to be answered. Further research needs to explore various protein types and doses or protein, and long-term adaptations. Varied outcomes may also be observed among trained, untrained, and older individuals. 

How to work out daily Guidelines.

While protein requirements vary depending on activity levels. Sedentary individuals generally require a lower protein intake compared to those involved in endurance or intermittent sports. The American College of Sports Medicine (ACSM) recommends a minimum daily protein intake of 0.8 grams per kilogram of body weight for sedentary adults. However, for individuals engaged in endurance sports, the recommended intake can range from 1.2 to 1.6 grams per kilogram of body weight, depending on the intensity and duration of training. Intermittent sports, such as strength training, often involve higher-intensity workouts and may require even higher protein intakes. The ACSM suggests a range of 1.4 to 2.0 grams per kilogram of body weight for those participating in intermittent sports. While these recommendations are general guidelines, and individual needs may vary based on factors such

Protein requirements may also be higher based on several factors beyond activity levels. Older individuals, illness, injury, and being in a calorie deficit may require increased protein needs. As people age, their muscle mass may decline, necessitating increased protein intake to maintain muscle health. During illness or injury, the body requires more nutrients, including protein, for recovery. Finally, individuals aiming to build muscle or lose fat may need increased protein to support their goals and minimise the risk of losses in lean tissue.

Table: Protein recommendations per kg of bodyweight relative to activity levels.

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