Table 2.
Effects of protein supplementation on changes in lean body mass
| Groups/subgroups | SMD | 95% CI | Number of trials/intervention groups | P‐value | I 2 (%) |
|---|---|---|---|---|---|
| All RCT | 0.22 | 0.15:0.29 | 66/93 | <0.01 | 7 |
| RCT without resistance exercise | 0.21 | ‐0.15:0.58 | 6/6 | 0.38 | 25 |
| RCT with resistance exercise (RE) | 0.22 | 0.14:0.30 | 62/87 | <0.01 | 6.2 |
| <65 years old | 0.25 | 0.16:0.35 | 48/70 | <0.01 | 8.1 |
| ≥65 years old | 0.13 | −0.00:0.28 | 14/17 | 0.06 | 6.2 |
| RCT with RE reporting protein ingestion | 0.19 | 0.11:0.28 | 51/72 | <0.01 | 6.9 |
| RCT with RE ingesting <1.2 g/kg/day | −0.14 | −0.56:0.27 | 4/4 | 0.35 | 0 |
| RCT with RE ingesting 1.2–1.59 g/kg/day | 0.17 | 0.06:0.28 | 24/34 | <0.01 | 0 |
| <65 years old | 0.15 | −0.02:0.31 | 15/23 | 0.07 | 2.8 |
| ≥65 years old | 0.20 | 0.02:0.37 | 9/11 | 0.03 | 0 |
| RCT with RE ingesting ≥1.6 g/kg/day | 0.30 | 0.17:0.43 | 23/34 | <0.01 | 0 |
| <65 years old | 0.30 | 0.17:0.43 | 23/34 | <0.01 | 0 |
| ≥65 years old a | ‐ | ‐ | ‐ | ‐ | ‐ |
|
Meta regression – protein ingestion as a continuous variable (g/kg BW/day) in all RCT reporting protein ingestion |
0.13 | −0.00:0.26 | 55/77 | 0.06 | NA |
| Meta regression – protein ingestion as a continuous variable (g/kg BW/day) in studies using RE | 0.14 | 0.00:0.27 | 51/72 | 0.04 | NA |
BW, body weight; CI, confidence intervals; NA, not applicable; RCT, randomized clinical trials; RE, resistance exercise; SMD, standardized mean deviation.
a
No studies in the dataset.