Impact of Overnight Fasted State Versus Fed State on Adaptations to Resistance Training: A Randomized Clinical Trial.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 40335157 · doi:10.1123/ijsnem.2024-0215
What was done
Twenty-eight young adults were randomly assigned to a fasted resistance training group (Fast-RT, n = 15) or a fed resistance training group (Fed-RT, n = 13). Both groups performed 12 weeks of resistance training twice weekly, either after an overnight fast or 1 to 2 hours after consuming a carbohydrate-rich meal, paired with isocaloric nutritional guidance. Measurements before and after 12 weeks included dual-energy X-ray absorptiometry for body composition, ultrasonography for quadriceps muscle thickness, one repetition maximum tests for bench press and knee extension, and muscle power in knee extension.
What was found
Both groups showed significant increases over time (p time <= .01) with no significant differences between groups. Quadriceps muscle thickness increased by 1.21 cm in Fast-RT and 1.18 cm in Fed-RT (p Group x Time = .871). Bench press maximum strength increased by 10.53 kg in Fast-RT and 4.89 kg in Fed-RT (p Group x Time = .268). Knee extension maximum strength increased by 28.53 kg in Fast-RT and 29.31 kg in Fed-RT (p Group x Time = .846). Knee extension mean power at 70% 1RM increased by 59.28 W in Fast-RT and 46.21 W in Fed-RT (p Group x Time = .616), while maximal power increased by 100.65 W in Fast-RT and 54.76 W in Fed-RT (p Group x Time = .409).
Why it matters
Performing resistance training in an overnight fasted versus fed state yields comparable strength, power, and hypertrophy adaptations over 12 weeks when dietary intake is isocaloric.
Limits
The sample size was small with 28 participants. The study was conducted only in young adults using a twice-weekly training frequency. Specific numerical results for dual-energy X-ray absorptiometry body composition were omitted from the abstract.