Table 5.
Summary of Findings— Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool.
| Outcome | Participants (n) (WP: Placebo) | RCT (n) | WMD (95% CI) | Statistical Significance * | Quality of Evidence (GRADE) | Due to | Comments | ||
|---|---|---|---|---|---|---|---|---|---|
| FFM | Global | 123:123 | 8 | 0.26 (−0.32, −0.83) | None | ⊕⊕◯◯◯ Low | Imprecision | Range of effect possibly underestimated by random statistics and low number of events. | |
| WP type | WPC | 57:57 | 3 | 0.17 (−0.58, 0.92) | None | ⊕⊕◯◯◯ Low | Imprecision | Low sample size. | |
| WPI | 53:51 | 6 | 0.38 (−0.53, 1.30) | ||||||
| Protein percentage (%) | 96–100 | 27:28 | 2 | 0.06 (−0.99, 1.11) | None | ⊕⊕◯◯◯ Low | Risk of bias | Only one study evaluated at low risk, others had consistent failures in randomization and in the selection of the reported result. | |
| 81–95 | 38:39 | 3 | 0.22 (−0.76, 1.19) | ||||||
| 51–80 | 48:51 | 2 | 0.40 (−0.61, 1.41) | ||||||
| Physical activity level | Sporadic or recreational | 44:44 | 2 | 0.21 (−0.76, 1.17) | None | ⊕⊕⊕◯◯ Moderate | Risk of bias | Presence of deviations from the intended interventions and inconsistencies in randomization. | |
| Regular | 71:71 | 5 | 0.26 (−0.32, 0.84) | ||||||
| FM | Global | 123:123 | 8 | −0.96 (−1.37, −0.55) | p < 0.001 | ⊕⊕⊕⊕◯ High | Risk of bias | Only one low-risk study. | |
| WP type | WPC | 57:57 | 3 | −0.63 (−1.19, −0.06) | p = 0.030 | ⊕⊕⊕⊕◯ High | Risk of bias | Only one low-risk study. | |
| WPI | 110:108 | 5 | −0.66 (−1.13, −0.20) | None | |||||
| Protein percentage (%) | 96–100 | 27:28 | 2 | −0.23 (−0.97, 0.50) | None | ⊕⊕⊕◯◯ Moderate | Imprecision | Range of effect possibly underestimated by random statistics and low number of events. | |
| 81–95 | 38:39 | 3 | −0.89 (−1.83, 0.06) | None | |||||
| 51–80 | 48:51 | 2 | −1.53 (−2.13, −0.93) | p < 0.001 | |||||
| Global | 113:118 | 7 | −0.99 (−1.41, −0.57) | - | ⊕◯◯◯◯ Very low | Indirect evidence | Metaregression not performed by the low number of studies (Figure 5b). | ||
| Physical activity level | Sporadic or recreational | 44:44 | 2 | −0.92 (−1.87, 0.03) | None | ⊕⊕⊕◯◯ Moderate | Risk of bias | Measure flaw (participants were not under the same restrictions to practice physical activity outside the study). | |
| Regular | 71:71 | 5 | −0.95 (−1.70, −0.19) | p = 0.014 | |||||
* None: value of p > 0.05. FFM: fat-free mass. FM fat mass. WP: whey protein. WPI: whey protein isolated. WPC: whey protein concentrate.