Macro partitioning
Whey protein supplementation (concentrated, hydrolyzed, or isolated) significantly reduces fat mass compared to isocaloric carbohydrate placebos in healthy adults undergoing resistance training, but does not significantly increase fat-free mass.
If you are doing resistance training, switching from a carbohydrate-based post-workout drink to whey protein may help you lose a small amount of fat mass over ~2 months. Do not expect this to build muscle mass; the study found no significant difference in fat-free mass gains between whey and placebo groups.
The weighted mean difference (WMD) was statistically significant for FM loss (WMD = −0.96, 95% CI = −1.37, −0.55, p < 0.001)... There was no significant effect on FFM in any of the scenarios investigated (p > 0.05).
Why this rating
Meta-analysis of RCTs, but the authors note 'low methodological quality' and 'low risk of bias' in only one study.
Source
Comparative Meta-Analysis of the Effect of Concentrated, Hydrolyzed, and Isolated Whey Protein Supplementation on Body Composition of Physical Activity Practitioners
Luis Henrique Almeida Castro et al. · Nutrients · 2019
DOI 10.3390/nu11092047
More from this paper
- Concentrated Whey Protein (WPC) with 51-80% protein content is specifically effective for fat mass loss, whereas Hydrolyzed (WPH) and Isolated (WPI) forms did not show statistically significant fat loss effects in subgroup analyses.Moderate
- Whey protein supplementation significantly reduces fat mass only in 'regular physical activity practitioners' and not in 'sporadic' practitioners or 'athletes' in subgroup analyses.Moderate
Related findings · Macro partitioning
- Total daily protein intake of 1.6 g/kg/day is sufficient for maximizing resistance training-induced muscle gains, with an upper confidence interval of 2.2 g/kg/day.Strong
- Resistance exercise training combined with sufficient dietary protein intake acts synergistically to maximize skeletal muscle hypertrophy, with protein intake saturating around 1.6 g/kg/day for general populations and potentially requiring 2.0-2.2 g/kg/day for resistance-trained individuals.Strong
- Trans fats should be completely eliminated from the diet, as they increase LDL cholesterol, decrease HDL cholesterol, and are directly associated with increased coronary risk.Strong
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