Per meal, and when.
Two ideas dominate this topic: that there's a ceiling on how much protein a single meal can use, and that there's a window after training when it counts double. Both contain something true, and both are usually overstated.
The per-meal figure
The common recommendation is 0.4 g per kg of body weight per meal, across three to four meals. For a 75 kg person that's about 30 g per meal, four times a day — which conveniently lands near 120 g total.
This comes from studies measuring muscle protein synthesis after a single dose. In young adults, the response rises with dose up to roughly 20–25 g and then flattens; adding more doesn't push it much higher. That flattening is where the "you can only absorb 30 g of protein at a time" claim comes from.
That claim is wrong as stated. You absorb essentially all the protein you eat. What plateaus is one specific measurement — the rate of muscle protein synthesis in the hours after a meal — not absorption, and not usefulness.
The distinction matters. Protein above the plateau still gets digested, still enters your amino acid pool, and still does the many other jobs protein does: enzymes, hormones, immune function, skin, hair, gut lining. It is not wasted; it's just not going disproportionately into new muscle.
The ceiling is softer than it sounds
Several things push the useful per-meal dose above 25 g:
- Whole foods behave differently from isolated protein. Much of the early research used whey, which digests fast. A steak with vegetables releases amino acids over a much longer period, extending the response.
- Bigger people need more. The dose scales with lean mass. 25 g is a solid meal for a 60 kg person and a modest one for a 100 kg person.
- Older adults need more per meal, not just per day. Anabolic resistance means the same dose produces a weaker response, and research suggests something closer to 35–40 g is needed to properly trigger it after about 60.
- The ceiling may not exist as described. A 2023 study by Trommelen and colleagues gave participants 100 g of protein in one sitting and tracked it over 12 hours. The body kept using it — synthesis stayed elevated far longer than the earlier short-window studies could detect. The earlier work wasn't wrong; it just stopped measuring too early.
Does the anabolic window exist?
The claim was that you had roughly 30–60 minutes after training to consume protein or forfeit much of the benefit. It made post-workout shakes feel urgent, which suited the people selling them.
The current picture, argued most influentially by Aragon and Schoenfeld, is that the window is far wider than claimed — measured in hours, not minutes — and that total daily protein intake dominates the outcome. When studies control for total intake, timing effects mostly disappear.
The nuance worth keeping: if you trained fasted, you've gone a long time without amino acids and eating reasonably soon is sensible. If you had a normal meal two hours before, you're still digesting it and there's no urgency at all.
Practical version: eat protein within a few hours of training. That's it. Sprinting home to a shake is not doing anything a normal dinner wouldn't.
Does spreading it out actually help?
Evenly distributed protein — four meals of 35 g rather than 10 g, 20 g and 90 g — does appear modestly better for muscle protein synthesis. It's a real effect, and it's small.
It's also worth noticing where the practical benefit really comes from. Most people's protein is heavily back-loaded: minimal at breakfast, moderate at lunch, most of it at dinner. Fixing that usually doesn't just redistribute intake — it increases it, because a 10 g breakfast becomes a 35 g breakfast and nothing else shrinks to compensate.
So the advice is worth following. Just be clear that the main win is probably the extra total protein, not the distribution itself.
Protein before bed
Casein — the slow-digesting protein in dairy — taken before sleep does raise overnight muscle protein synthesis in controlled studies. This one holds up reasonably well.
Whether it changes anything for you depends on whether you're already hitting your daily target. If you are, a bedtime portion is a small optimisation. If you're 40 g short every day, it's a convenient way to close the gap — and the gap is the thing that mattered.
What happens to protein you don't need
Nothing dramatic. Excess amino acids are broken down; the nitrogen is converted to urea and excreted in urine, and the remainder is used for energy or, in a calorie surplus, eventually stored as fat.
Protein is an inefficient way to gain fat — the conversion is costly and around 20–30% of its energy is spent on digestion. But "protein doesn't count toward calories" is false. In a large enough surplus, it contributes like anything else.
What to actually do
- Hit your daily total. This is 90% of the outcome. Everything below is refinement.
- Split it across three or four meals at roughly 0.4 g/kg each — for most people, 30–40 g a meal.
- Fix breakfast first. It's almost always the weakest meal, and it's the cheapest to improve.
- Eat protein within a few hours of training. No stopwatch required.
- Consider dairy before bed if you're already consistent and want a marginal gain.
If you're doing the first two, you've captured nearly all of the available benefit. The rest is tuning at the edges.
See where your day is lopsided
PRO.TEIN logs each entry against a meal, so the pattern shows up on its own — usually as a breakfast that isn't pulling its weight.
Where these numbers come from
Drawing on: Morton, Schoenfeld and colleagues for per-meal dosing and the resistance-training literature; Aragon & Schoenfeld's review of nutrient timing for the anabolic window; Trommelen et al. (2023), Cell Reports Medicine, for the 100 g single-dose study; and the PROT-AGE group for per-meal recommendations in older adults.
This is general information, not medical advice. If you have kidney or liver disease, diabetes, are pregnant or breastfeeding, or are managing any medical condition, speak to a doctor or registered dietitian before changing your diet.