Short-term changes in human metabolism following a 5-h delay of the light-dark and behavioral cycle.

Experimental inversion of circadian and behavioral rhythms by 12 h adversely affects markers of metabolic health. We investigated the effects of a more modest 5-h delay in behavioral cycles. Fourteen participants completed an 8-day in-patient laboratory protocol, with controlled sleep-wake opportunities, light-dark cycles, and diet.

Timing of daily calorie loading affects appetite and hunger responses without changes in energy metabolism in healthy subjects with obesity.

Morning loaded calorie intake in humans has been advocated as a dietary strategy to improve weight loss. This is also supported by animal studies suggesting time of eating can prevent weight gain. However, the underlying mechanisms through which timing of eating could promote weight loss in humans are unclear.

Circadian Rhythms in Resting Metabolic Rate Account for Apparent Daily Rhythms in the Thermic Effect of Food.

Context: Daily variation in the thermic effect of food (TEF) is commonly reported and proposed as a contributing factor to weight gain with late eating. However, underlying circadian variability in resting metabolic rate (RMR) is an overlooked factor when calculating TEF associated with eating at different times of the day.

Objective: This work aimed to determine whether methodological approaches to calculating TEF contribute to the reported phenomena of daily variation in TEF.

Mealtime: A circadian disruptor and determinant of energy balance?

Circadian rhythms play a critical role in the physiological processes involved in energy metabolism and energy balance (EB). A large array of metabolic processes, including the expression of many energy-regulating endocrine hormones, display temporal rhythms that are driven by both the circadian clock and food intake. Mealtime has been shown to be a compelling zeitgeber in peripheral tissue rhythms.

Assessing the influence of fasted and postprandial states on day-to-day variability of appetite and food preferences.

Introduction: Ratings of subjective appetite and food hedonics provide valuable information about energy and macronutrient intake. Ensuring reproducibility of measures of subjective appetite, and food liking and wanting is essential for accurate understanding about their implementation in intervention studies.

Methods: Nineteen participants participated in two separate 10-h test days consisting of 6 test meals.

Measurement duration affects the calculation of whole body protein turnover kinetics but not between-day variability.

Background: Assessment of whole body protein turnover (WBPT) can provide fundamental information about protein kinetics which underpins the conservation of lean tissue. Reliability and methodology studies on the measurement of WBPT are scarce. This study aimed to assess the effects of urine collection duration (9 versus 12 h) and the reproducibility of WBPT with the end product method calculated from ammonia as the end product.

Methodological considerations for meal-induced thermogenesis: measurement duration and reproducibility.

Meal-induced thermogenesis (MIT) research findings have been highly inconsistent, in part, due to the variety of durations and protocols used to measure MIT. In the present study, we aimed to determine the following: (1) the proportion of a 6 h MIT response completed at 3, 4 and 5 h; (2) the associations between the shorter durations and the 6 h measures; (3) whether shorter durations improved the reproducibility of the measurement. MIT was measured in response to a 2410 kJ mixed composition meal in ten individuals (five males and five females) on two occasions.