Two weeks of early time-restricted feeding (eTRF) improves skeletal muscle insulin and anabolic sensitivity in healthy men

Abstract

Background Altering the temporal distribution of energy intake (EI) and introducing periods of intermittent fasting (IF) exert important metabolic effects. Restricting EI to earlier in the day [early time-restricted feeding (eTRF)] is a novel type of IF. Objectives We assessed the chronic effects of eTRF compared with an energy-matched control on whole-body and skeletal muscle insulin and anabolic sensitivity. Methods Sixteen healthy males (aged 23 ± 1 y; BMI 24.0 ± 0.6 kg·m−2) were assigned to 2 groups that underwent either 2 wk of eTRF (n = 8) or control/caloric restriction (CON:CR; n = 8) diet. The eTRF diet was consumed ad libitum and the intervention was conducted before the CON:CR, in which the diet was provided to match the reduction in EI and body weight observed in eTRF. During eTRF, daily EI was restricted to between 08:00 and 16:00, which prolonged the overnight fast by ∼5 h. The metabolic responses to a carbohydrate/protein drink were assessed pre- and post-interventions following a 12-h overnight fast. Results When compared with CON:CR, eTRF improved whole-body insulin sensitivity [between-group difference (95% CI): 1.89 (0.18, 3.60); P = 0.03; η2p = 0.29] and skeletal muscle uptake of glucose [between-group difference (95% CI): 4266 (261, 8270) μmol·min−1·kg−1·180 min; P = 0.04; η2p = 0.31] and branched-chain amino acids (BCAAs) [between-group difference (95% CI): 266 (77, 455) nmol·min−1·kg−1·180 min; P = 0.01; η2p = 0.44]. eTRF caused a reduction in EI (∼400 kcal·d−1) and weight loss (−1.04 ± 0.25 kg; P = 0.01) that was matched in CON:CR (−1.24 ± 0.35 kg; P = 0.01). Conclusions Under free-living conditions, eTRF improves whole-body insulin sensitivity and increases skeletal muscle glucose and BCAA uptake. The metabolic benefits of eTRF are independent of its effects on weight loss and represent chronic adaptations rather than the effect of the last bout of overnight fast. This trial was registered at clinicaltrials.gov as NCT03969745.

A randomized controlled trial to isolate the effects of fasting and energy restriction on weight loss and metabolic health in lean adults

“…In addition, one recent study has even reported that diet-induced reductions in fat-free mass can be offset by only slightly increasing the daily fasting period from 18 to 20 hours (27). It therefore appears that losses of fat-free mass are possible even with less protracted periods of limited nutrient delivery than implemented in the present study, and so, further research is needed to examine the potential for a more sustained catabolic state to result in atrophy of lean soft tissue mass or to improve anabolic sensitivity (16).…”

“…For example, early time-restricted feeding (fasting from 1500 h daily) in men with prediabetes improved their insulin sensitivity within 5 weeks without losing weight, simply by extending their usual overnight fast to 18 hours (15). This effect on insulin sensitivity has since been confirmed in healthy young adults after only 2 weeks of fasting for 16 hours from 1600 h each day (16) and after 8 weeks of simply restricting typical daily meals to an 11-hour period ending at 1900 h (17). The other common form of intermittent fasting that routinely involves such protracted postabsorptive periods is complete alternate-day fasting (no energy intake whatsoever during fasting days), yet almost no research has examined fasting periods that span an entire day.…”

Effects of Feeding Time on Markers of Muscle Metabolic Flexibility Following Acute Aerobic Exercise in Trained Mice Undergoing Time Restricted Feeding

“…In our study, TRF had no effect on body weight over the 8-week period; however, hindlimb muscle mass was smaller in both fasting groups. Some groups have shown a maintenance of muscle mass during TRF, but most of these studies combine the fasting with resistance exercise [ 21 , 22 , 23 , 24 ], whereas we utilized endurance exercise which may have a less potent anabolic effect on the muscle. Interestingly, it has been shown that TRF decreased IGF-1 and testosterone levels [ 24 ].…”

Chrono-Nutrition Has Potential in Preventing Age-Related Muscle Loss and Dysfunction

“…The TRF induced between 0800 and 1400 improved the 24-h glucose levels and increased the expression of the anti-aging gene SIRT1 and the autophagy gene LC3A in the blood compared with the TRF induced between 0800 and 2000 (Jamshed et al, 2019). In terms of skeletal muscle function, 2 weeks of TRF induced between 0800 and 1600 improves insulin and anabolic responses in the skeletal muscle of healthy young men (Jones et al, 2020). Indeed, TRF increased the skeletal muscle uptake of glucose and branchedchain amino acids (BCAAs) (Jones et al, 2020).…”

“…In terms of skeletal muscle function, 2 weeks of TRF induced between 0800 and 1600 improves insulin and anabolic responses in the skeletal muscle of healthy young men (Jones et al, 2020). Indeed, TRF increased the skeletal muscle uptake of glucose and branchedchain amino acids (BCAAs) (Jones et al, 2020). The effects of TRF in men who are overweight/obese have been elucidated using the circadian transcriptome of skeletal muscle (Lundell et al, 2020).…”