TY - JOUR
T1 - Time-restricted feeding plus resistance training in active females
T2 - A randomized trial
AU - Tinsley, Grant M.
AU - Moore, M. Lane
AU - Graybeal, Austin J.
AU - Paoli, Antonio
AU - Kim, Youngdeok
AU - Gonzales, Joaquin U.
AU - Harry, John R.
AU - Vandusseldorp, Trisha A.
AU - Kennedy, Devin N.
AU - Cruz, Megan R.
N1 - Funding Information:
Supported by MTI Biotech Inc. and Texas Tech University. In-kind donations were received from MTI Biotech Inc. (HMB and placebo capsule supplements) and Dymatize Enterprises (whey protein supplements). These entities did not play a role in the overall design or execution of the study, the analysis and interpretation of the data, or the presentation of the results found in this article.
Publisher Copyright:
Copyright © American Society for Nutrition 2019.
PY - 2019/9/1
Y1 - 2019/9/1
N2 - A very limited amount of research has examined intermittent fasting (IF) programs, such as time-restricted feeding (TRF), in active populations. Objective: Our objective was to examine the effects of TRF, with or without β-hydroxy β-methylbutyrate (HMB) supplementation, during resistance training (RT). Methods: This study employed a randomized, placebo-controlled, reduced factorial design and was double-blind with respect to supplementation in TRF groups. Resistance-trained females were randomly assigned to a control diet (CD), TRF, or TRF plus 3 g/d HMB (TRFHMB). TRF groups consumed all calories between 1200 h and 2000 h, whereas the CD group ate regularly from breakfast until the end of the day. All groups completed 8 wk of supervised RT and consumed supplemental whey protein. Body composition, muscular performance, dietary intake, physical activity, and physiological variables were assessed. Data were analyzed prior to unblinding using mixed models and both intention-to-treat (ITT) and per protocol (PP) frameworks. Results: Forty participants were included in ITT, and 24 were included in PP. Energy and protein intake (1.6 g/kg/d) did not differ between groups despite different feeding durations (TRF and TRFHMB: ∼7.5 h/d; CD: ∼13 h/d). Comparable fat-free mass (FFM) accretion (+2% to 3% relative to baseline) and skeletal muscle hypertrophy occurred in all groups. Differential effects on fat mass (CD: +2%; TRF: -2% to -4%; TRFHMB: -4% to -7%) were statistically significant in the PP analysis, but not ITT. Muscular performance improved without differences between groups. No changes in physiological variables occurred in any group, and minimal side effects were reported. Conclusions: IF, in the form of TRF, did not attenuate RT adaptations in resistance-trained females. Similar FFM accretion, skeletal muscle hypertrophy, and muscular performance improvements can be achieved with dramatically different feeding programs that contain similar energy and protein content during RT. Supplemental HMB during fasting periods of TRF did not definitively improve outcomes. This study was prospectively registered at clinicaltrials.gov as NCT03404271.
AB - A very limited amount of research has examined intermittent fasting (IF) programs, such as time-restricted feeding (TRF), in active populations. Objective: Our objective was to examine the effects of TRF, with or without β-hydroxy β-methylbutyrate (HMB) supplementation, during resistance training (RT). Methods: This study employed a randomized, placebo-controlled, reduced factorial design and was double-blind with respect to supplementation in TRF groups. Resistance-trained females were randomly assigned to a control diet (CD), TRF, or TRF plus 3 g/d HMB (TRFHMB). TRF groups consumed all calories between 1200 h and 2000 h, whereas the CD group ate regularly from breakfast until the end of the day. All groups completed 8 wk of supervised RT and consumed supplemental whey protein. Body composition, muscular performance, dietary intake, physical activity, and physiological variables were assessed. Data were analyzed prior to unblinding using mixed models and both intention-to-treat (ITT) and per protocol (PP) frameworks. Results: Forty participants were included in ITT, and 24 were included in PP. Energy and protein intake (1.6 g/kg/d) did not differ between groups despite different feeding durations (TRF and TRFHMB: ∼7.5 h/d; CD: ∼13 h/d). Comparable fat-free mass (FFM) accretion (+2% to 3% relative to baseline) and skeletal muscle hypertrophy occurred in all groups. Differential effects on fat mass (CD: +2%; TRF: -2% to -4%; TRFHMB: -4% to -7%) were statistically significant in the PP analysis, but not ITT. Muscular performance improved without differences between groups. No changes in physiological variables occurred in any group, and minimal side effects were reported. Conclusions: IF, in the form of TRF, did not attenuate RT adaptations in resistance-trained females. Similar FFM accretion, skeletal muscle hypertrophy, and muscular performance improvements can be achieved with dramatically different feeding programs that contain similar energy and protein content during RT. Supplemental HMB during fasting periods of TRF did not definitively improve outcomes. This study was prospectively registered at clinicaltrials.gov as NCT03404271.
KW - body composition
KW - energy restriction
KW - fat loss
KW - intermittent energy restriction
KW - intermittent fasting
KW - muscle mass
KW - muscular strength
KW - protein
KW - resistance exercise
KW - weight training
UR - http://www.scopus.com/inward/record.url?scp=85071627721&partnerID=8YFLogxK
U2 - 10.1093/ajcn/nqz126
DO - 10.1093/ajcn/nqz126
M3 - Article
C2 - 31268131
AN - SCOPUS:85071627721
VL - 110
SP - 628
EP - 640
JO - American Journal of Clinical Nutrition
JF - American Journal of Clinical Nutrition
SN - 0002-9165
IS - 3
ER -