The Myth That Your Body Can Only Absorb 25g of Protein Per Meal — Busted

The Myth That "Your Body Can Only Absorb 25 Grams of Protein Per Meal" — Busted!

Ever heard advice like this: "Why eat a huge amount of protein in one sitting? Your body can only use about 20-25 grams per meal anyway. The rest just gets wasted."

That's why so many people recommend spreading protein intake evenly across meals instead of loading up on one big portion. But a recent study published in the journal Cell Reports Medicine (2023) by Trommelen et al. proves this assumption is wrong.

Illustration: the journey of protein from food to the bloodstream and into muscle, plus a comparison of the muscle-building response duration between 25g and 100g of protein.

How Was This Study Conducted?

Researchers recruited 36 healthy young men who had just completed a resistance training session. They were randomly split into three groups and given a drink containing one of the following:

• No protein (placebo)
• 25 grams of protein
• 100 grams of protein

What makes this study special is that the milk protein given to participants was "tagged" using special isotopes — essentially tiny tracers that allowed researchers to follow exactly where the amino acids from that protein went inside the body. Were they built into muscle, burned for energy, or did they just pass through? The study tracked this for a full 12 hours, far longer than previous studies, which usually only observed for about 6 hours.

Surprising Results

1. More protein, longer and bigger effects

In the group that consumed 100 grams of protein, amino acid levels in the blood remained elevated even after 12 hours. In the 25-gram group, the effect had already faded after about 5 hours.

2. Muscle building keeps going, with no upper limit

Muscle protein synthesis in the 100-gram group actually increased further during the 4-12 hour period, not just in the first few hours.

3. "Excess" protein isn't wasted

More than 85% of the protein consumed was actually used to build body tissue, not burned off as energy as previously believed. The increase in amino acid oxidation (burning) from a large protein dose turned out to be negligible.

4. Cell signaling doesn't reflect what's actually happening

The chemical signal in muscle cells (commonly used as an indicator of muscle-building activity, known as mTOR) is only active for a short time — less than 4 hours. But the actual muscle-building process continues for up to 12 hours. In other words, if you only look at cell signaling, it seems like the process is "done", when in reality the body is still working hard behind the scenes.

What Does This Mean For Us?

If you eat a large portion in one sitting — say a steak or chicken breast containing 100 grams of protein at once — your body can still make full use of all of it. It just takes longer to digest and absorb.

This means a more flexible eating pattern, including eating fewer but larger meals, or following a restricted eating window (intermittent fasting), won't harm your muscle maintenance, as long as your total daily protein intake is sufficient.

So, What About OMAD (One Meal A Day)?

For a long time, many people have said that OMAD, eating just once a day, is "useless" for those trying to maintain or build muscle mass. The reasoning was always the same: since the body was thought to only "process" 20-25 grams of protein per meal, eating one large meal a day was considered wasteful, with the rest simply going to waste.

But with this study, that assumption needs to be corrected. As it turns out:

• The body can still make use of large amounts of protein (100 grams or more) consumed at once, it just takes longer, up to 12 hours or more.
• More than 85% of the protein consumed is genuinely used to build tissue, not wasted.
• Muscle building actually remains active and even increases during hours 4-12 after eating, far beyond the duration that was previously considered the "anabolic window".

So the conclusion is: OMAD is not a wasted eating pattern, as long as your daily protein needs are genuinely met within that single meal. For example, if your protein requirement is around 100-150 grams per day and you consume all of it in one sitting, your body will still process it efficiently throughout the day, rather than simply discarding the excess.

The key takeaway is that what matters isn't how often you eat, but whether your total daily protein intake is sufficient. If you're comfortable and consistent with OMAD, and that one large meal allows you to hit your daily protein target, your muscles can theoretically still build optimally. On the other hand, if OMAD makes it difficult for you to reach your total daily protein needs (for example, because you feel too full to finish such a large portion), then a more frequent eating pattern might be the more realistic choice.

Important Notes

This study was conducted on healthy young men who had just finished resistance training. The results may not apply exactly the same way to other groups, such as older adults or people who rarely exercise, who generally have a slower bodily response to protein intake.

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Source: Trommelen, J., et al. (2023). The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans. Cell Reports Medicine, 4, 101324.