Author(s): YAVETZ, R., LAHAV, Y., STERNFELD, R., GEPNER, Y., Institution: TEL AVIV UNIVERSITY, Country: ISRAEL, Abstract-ID: 1382

INTRODUCTION:
Resistance training (RT) and time-restricted eating (TRE) are established lifestyle modalities for enhancing body composition. Yet, their combined effect has yet to be determined. This study aimed to determine the effects of RT with either TRE or normal diet (ND) on fat mass (FM) and fat-free mass (FFM) in obese men with metabolic syndrome (MetS).
METHODS:
In this randomized controlled trial, 32 obese men with MetS (aged 49.1±5.8y, BMI 31.0±4.0kg/m2, body fat 33.7±4.6%) were randomly assigned to TRE of 8 hours of eating and 16 hours of fasting (n=16) or ND (n=16) for ten weeks. Both groups consumed an isocaloric diet and underwent the same supervised whole-body RT three times per week. Body composition changes were assessed using dual-energy X-ray absorptiometry (DXA) scans pre- and post-intervention. A 2-way repeated measures ANOVA evaluated the within- and between-group differences and interaction.
RESULTS:
After 10 weeks of intervention, body weight significantly decreased for the TRE group (-1±1.4 kg, p=0.02) and slightly increased (0.3±1.8 kg) for the ND group. Both dietary interventions decrease FM (TRE: -2.3±1.2 kg, ND: -2.2±1.7 kg, p<0.001 for both), with no significant differences between the groups. Although both groups showed a considerable improvement in FFM (TRE: 1.3±1.1 kg, p=0.001, ND: 2.5±0.9 p=0.001), the increase was more substantial in the ND group (p=0.003), indicating a differential effect of diet on muscle mass gains in combination with RT.
CONCLUSION:
Both TRE and ND, along with RT, improve body composition in obese men with MetS, but ND was more effective in enhancing FFM. This suggests that meal timing and duration can influence muscle mass.