This exploratory study investigated the effects of early v. delayed time-restricted eating (TRE) plus caloric restriction (CR) on body weight, body composition and cardiometabolic parameters in adults with overweight and obesity. Adults (20–40 years) were randomised to one of three groups for 8 weeks: early time-restricted eating (eTRE; 08.00–16.00) plus CR, delayed time-restricted eating (dTRE; 12.00–20.00) plus CR or only CR (CR; 08.00–20.00). All groups were prescribed a 25 % energy deficit relative to daily energy requirements. Thirteen participants completed the study in the eTRE and CR groups and eleven in the dTRE group (n 37). After the interventions, there was no significant difference between the three groups for any of the outcomes. Compared with baseline, significant decreases were observed in the body weight (eTRE group: −4·2 kg; 95 % CI, −5·6, −2·7; dTRE group: −4·8 kg; 95 % CI, −5·9, −3·7; CR: −4·0 kg; 95 % CI, −5·9, −2·1), fat mass (eTRE group: −2·9 kg; 95 % CI, −3·9, −1·9; dTRE group: −3·6 kg; 95 % CI, −4·6, −2·5; CR: −3·1 kg; 95 % CI, −4·3, −1·8) and fasting glucose levels (eTRE group: −4 mg/dl; 95 % CI, −8, −1; dTRE group: −2 mg/dl; 95 % CI, −8, 3; CR: −3 mg/dl; 95 % CI, −8, 2). In a free-living setting, TRE with a energetic deficit, regardless of the time of day, promotes similar benefits in weight loss, body composition and cardiometabolic parameters. However, given the exploratory nature of our study, further investigation is needed to confirm these findings.

Physical inactivity–gene interactions result in changes in gene expression, leading to phenotypic changes in the skeletal muscle cell. A subpopulation of those genes that show changes in expression during physical inactivity are candidates for the environment–gene interactions that cross a threshold of biological significance such that overt clinical disease occurs. AMP kinase, GLUT4 and myosin heavy chain IIx are proposed as candidates for physical inactivity-modulated genes that have an altered function that may trigger a crossing of a threshold to disease. Future experiments will be needed to test the validity of the ideas presented.

Current recommendations for energy requirements in the elderly are based on assumed levels of physical activity relative to BMR (1.5 x BMR). The main aim of the present study was to establish whether these recommendations might be applicable to a randomly-selected group of free-living elderly men (all over 75 years of age). BMR was measured by indirect calorimetry and total energy expenditure (TEE) by the doubly-labelled-water technique. Further aims included evaluating the applicability of a variety of BMR prediction equations and whether assessed quality of life reflected any measured indices of energy expenditure. The mean value for daily energy requirement was found to be 1.5 x BMR (89 J/kg per min) but with substantial inter-individual variation (SD 0-2 x BMR; 14 J/kg per min). The bias between measured TEE and TEE estimated (1.5 x BMR) from the various BMR predictions varied according to which equation was used (-10-+ 8% of the mean) with substantial 95 YO limits of agreement (28-30%of the mean). TEE and physical activity plus thermogenesis (TEE -BMR) were positively related to activities of daily living, but no relationships were apparent between these and perceived quality of life. It is concluded that, despite considerable inter-individual variability, national recommendations for energy requirements of elderly people are applicable to this randomly-selected group of free-living men over 75 years of age but that substantial variation exists when attempts are made to estimate TEE from measurements or predictions of BMR.