REF-154 · Zhou et al., 2023 · International Journal of Sport Nutrition and Exercise Metabolism, Vol. · Paper
Effects of Timing and Types of Protein Supplementation on Improving Muscle Mass, Strength, and Physical Performance in Adults Undergoing Resistance Training: A Network Meta-Analysis
Scale
116 RCTs, n=4711 participants, 11 timing strategies, 14 protein types; databases PubMed, Web of Science, Cochrane Library, SPORTDiscus searched to May 1, 2023.
Key Results
1. Timing (vs placebo, moderate certainty):
| Outcome | Most effective timing | Effect (abstract) |
|---|---|---|
| Fat-free mass | After exercise | MD +0.54 kg (95% CI 0.10, 0.99) |
| Skeletal muscle mass | After exercise | MD +0.34 kg (95% CI 0.10, 0.58) |
| Handgrip strength | At night | MD +2.85 kg (95% CI 0.49, 5.22) |
| Leg press strength | At night | MD +12.12 kg (95% CI 3.26, 20.99) |
Authors' conclusion: pre/post-exercise and night are the key recommended times to increase muscle mass and strength, respectively.
2. Protein type (moderate certainty):
Milk proteins (milk, whey protein, yogurt, casein, bovine colostrum), red meat and mixed protein were effective for gains in both muscle mass and strength.
Milk proteins are the preferred supplement type for improving muscle mass and strength (authors' conclusion).
3. Physical performance: no timing and no protein type significantly improved physical performance (timed up-and-go, 6-min walk, gait speed).
Practical Application
Network meta-analysis of 116 RCTs (n=4711) in adults doing resistance training: protein after exercise gave the largest gain in muscle mass (fat-free mass +0.54 kg, skeletal muscle +0.34 kg vs placebo), protein at night the largest gain in strength (handgrip +2.85 kg, leg press +12.12 kg); milk proteins, red meat and mixed protein worked for both mass and strength; no timing or type improved functional performance tests (moderate certainty). For a strength-training athlete: protein around the session for mass, protein before sleep for strength, milk-based sources first.
Not from this paper; the base's own practice: whey after the session and casein or milk protein before sleep, with the daily total from REF-151; per-serving amounts and meal counts are not given in this abstract.
Inference, not tested: the night-strength effect is consistent with the overnight MPS data in REF-155; the effect sizes here are small in absolute terms and were measured in resistance-training adults, not endurance athletes.
Do not expect a functional-performance change from timing or type alone (abstract: none of the performance tests improved).
Limitations
Adults undergoing resistance training, mixed ages and training status; not endurance athletes.
Performance outcomes were clinical/functional tests (timed up-and-go, 6-min walk, gait speed), not sport performance.
Network comparisons are largely indirect; the authors call for RCTs directly comparing timings and types.
Moderate certainty throughout.
How this entry was checked and changed
Why this level
(highest)
Content correction 2026-09-27
"Collagen and whey top-ranked for fat-free mass" and "collagen 10-15 g/day for connective tissue" -> not in the abstract (abstract names milk proteins, red meat and mixed protein); deleted.
"30 g whey within 1-2 h", "40 g casein 30 min before bed", "4-5 meals × 25-40 g" -> not in the abstract; relabelled as the base's own practice without amounts.
Added the abstract's effect sizes (MD +0.54/+0.34 kg mass; +2.85/+12.12 kg strength) and the null result for physical performance.
Sport "cycling, strength" -> strength (resistance-training trials).