The Impact of Time of Day on Energy Expenditure: Implications for Long-Term Energy Balance

Abstract

There is evidence to indicate that the central biological clock (i.e., our endogenous circadian system) plays a role in physiological processes in the body that impact energy regulation and metabolism. Cross-sectional data suggest that energy consumption later in the day and during the night is associated with weight gain. These findings have led to speculation that when, as well as what, we eat may be important for maintaining energy balance. Emerging literature suggests that prioritising energy intake to earlier during the day may help with body weight maintenance. Evidence from tightly controlled acute experimental studies indicates a disparity in the body’s ability to utilise (expend) energy equally across the day and night. Energy expenditure both at rest (resting metabolic rate) and after eating (thermic effect of food) is typically more efficient earlier during the day. In this review, we discuss the key evidence for a circadian pattern in energy utilisation and balance, which depends on meal timing. Whilst there is limited evidence that simply prioritising energy intake to earlier in the day is an effective strategy for weight loss, we highlight the potential benefits of considering the role of meal timing for improving metabolic health and energy balance. This review demonstrates that to advance our understanding of the contribution of the endogenous circadian system toward energy balance, targeted studies that utilise appropriate methodologies are required that focus on meal timing and frequency.

Chrononutrition during Pregnancy: A Review on Maternal Night-Time Eating

“…These findings are consistent with a meta-analysis of observational studies in adults, reporting an association between greater night-time energy intake and higher BMI [15]. Given that night time is a period with delayed gastric emptying [69], decreased thermic effect of food and reduced resting metabolic rate [70], consuming a large amount of energy during this period may be detrimental to metabolic processes during pregnancy by dysregulating circadian rhythms, disrupting hormone secretion and altering gut microbiome [2,71].…”

The Assessment of Daily Energy Expenditure of Commercial Saturation Divers Using Doubly Labelled Water

“…The participants’ body composition in the current study could not be measured, and further work should consider the influence of a diver’s body composition on the energy cost during a diving operation. In addition, those partaking in rotating shift patterns may also experience changes to their RMR and DEE as energy metabolism is subject to diurnal variation ( Shaw et al, 2019 ). This study’s sample size was insufficient to discern any differences between divers on different shift patterns, but future research and nutritional guidelines for saturation divers should consider this.…”

Stress Characterization is a more Reliable Approach for the Assessment of Metabolism than Blood Glucose Value

“…It is also evident that in repetitive stress attacks, the glycogen reserves of stressed organs are repeatedly depleted, and replenishment is ensured by adequately tailored nutrition and rest periods realized in inter-stress intervals. Importantly, the idea of post-exercise hypoglycaemia and hyperinsulinaemia is a well-documented phenomenon in which the replenishing mechanism exists regardless of food intake [2,13,18]. During inter-stress rest periods, glycogen and fat stores are replenished, and the cytosolic and mitochondrial ultrastructure required for the higher metabolic performance is regenerated or even further built-up.…”

“…The primary and second messenger characteristics of the inter-stress period basically differ from that of the stress reaction. Both are characterised by glucose mobilization, but in the anabolic nutritive state, insulin plays a fundamental role, while in acute stress metabolism of maximal metabolic performance, the main mediators are adrenaline, cortisol, glucagon and adenosine monophosphateactivated protein kinase; however, the role of a limited amount of insulin in achieving allostasis must also be emphasized [2,6,13,16,18].…”

“…As a result, acetyl coenzyme A molecules of free fatty acid origin are overproduced and cannot be completely metabolized during terminal oxidation and oxidative phosphorylation; therefore, toxic fatty acids accumulate, resulting in lipotoxicity [1,2]. The mitochondrial uncoupling phenomenon is also characteristic of this metabolic state: heat production increases at the expense of adenosine triphosphate synthesis, and this occurrence is a marker of inefficient metabolic processes [6,7,16,18]. These chronic stress phenomena inevitably lead to the development of reduced inducible metabolic reserve capacity, ultimately resulting in a decrease in the resting creatine phosphate/adenosine triphosphate ratio.…”