Time-restricted feeding plus resistance training in active females: a randomized trial.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 31268131 · doi:10.1093/ajcn/nqz126
What was done
Forty resistance-trained females completed 8 weeks of supervised resistance training with supplemental whey protein while randomized to one of three groups: a control diet (feeding window ~13 h/d), time-restricted feeding (TRF, feeding window ~7.5 h/d between 1200 h and 2000 h), or TRF plus 3 g/d beta-hydroxy beta-methylbutyrate (TRFHMB, double-blinded against TRF). Body composition, skeletal muscle hypertrophy, muscular performance, dietary intake, and physiological variables were assessed using intention-to-treat (ITT, n = 40) and per-protocol (PP, n = 24) analyses.
What was found
Energy and protein intake (1.6 g/kg/d) did not differ between groups. Fat-free mass accretion (+2% to 3% relative to baseline) and skeletal muscle hypertrophy were comparable across all groups. Muscular performance improved with no differences between groups, and physiological variables showed no changes. Fat mass changes (CD: +2%; TRF: -2% to -4%; TRFHMB: -4% to -7%) reached statistical significance in PP analysis but not in ITT. Adding HMB did not definitively improve outcomes.
Why it matters
Time-restricted feeding does not compromise resistance training adaptations, such as muscle hypertrophy or strength, in active women when total energy and protein intake are maintained.
Limits
The study had a small sample size and substantial attrition, with 40 participants in ITT dropping to 24 in the PP analysis. Fat loss differences between groups were not statistically significant in the primary ITT framework. Findings are restricted to resistance-trained females over an 8-week duration.
Cited by
- context In an 8-week hypercaloric resistance training study with morning fasted training, participants in the 16:8 time-restricted feeding group experienced greater fatigue and an inability to maintain leg training volume by the end of the intervention compared to standard feeding.