There are suggestions that large evening meals are associated with greater BMI. This study reviewed systematically the association between evening energy intake and weight in adults and aimed to determine whether reducing evening intake achieves weight loss. Databases searched were MEDLINE, PubMed, Cinahl, Web of Science, Cochrane Library of Clinical Trials, EMBASE and SCOPUS. Eligible observational studies investigated the relationship between BMI and evening energy intake. Eligible intervention trials compared weight change between groups where the proportion of evening intake was manipulated. Evening intake was defined as energy consumed during a certain time – for example 18.00–21.00 hours – or self-defined meal slots – that is ‘dinner’. The search yielded 121 full texts that were reviewed for eligibility by two independent reviewers. In all, ten observational studies and eight clinical trials were included in the systematic review with four and five included in the meta-analyses, respectively. Four observational studies showed a positive association between large evening intake and BMI, five showed no association and one showed an inverse relationship. The meta-analysis of observational studies showed a non-significant trend between BMI and evening intake (P=0·06). The meta-analysis of intervention trials showed no difference in weight change between small and large dinner groups (−0·89 kg; 95 % CI −2·52, 0·75, P=0·29). This analysis was limited by significant heterogeneity, and many trials had an unknown or high risk of bias. Recommendations to reduce evening intake for weight loss cannot be substantiated by clinical evidence, and more well-controlled intervention trials are needed.

Circadian rhythms act to optimise many aspects of our biology and thereby ensure that physiological processes are occurring at the most appropriate time. The importance of this temporal control is demonstrated by the strong associations between circadian disruption, morbidity and disease pathology. There is now a wealth of evidence linking the circadian timing system to metabolic physiology and nutrition. Relationships between these processes are often reciprocal, such that the circadian system drives temporal changes in metabolic pathways and changes in metabolic/nutritional status alter core molecular components of circadian rhythms. Examples of metabolic rhythms include daily changes in glucose homeostasis, insulin sensitivity and postprandial response. Time of day alters lipid and glucose profiles following individual meals whereas, over a longer time scale, meal timing regulates adiposity and body weight; these changes may occur via the ability of timed feeding to synchronise local circadian rhythms in metabolically active tissues. Much of the work in this research field has utilised animal and cellular model systems. Although these studies are highly informative and persuasive, there is a largely unmet need to translate basic biological data to humans. The results of such translational studies may open up possibilities for using timed dietary manipulations to help restore circadian synchrony and downstream physiology. Given the large number of individuals with disrupted rhythms due to, for example, shift work, jet-lag, sleep disorders and blindness, such dietary manipulations could provide widespread improvements in health and also economic performance.

ABSTRACT

Objective: The goal of the study was to assess the efficacy of sertraline in the treatment of the night eating syndrome (NES). Method: Thirty-four outpatients diagnosed with NES were randomly assigned to receive either sertraline (n = 17) or placebo (n = 17) in an 8-week, double-blind, flexible-dose (50–200 mg/day) study. We used the mixed effects linear regression model to analyze change in the primary outcome measure, the Clinical Global Impression of Improvement Scale (CGI-I). Secondary outcomes included changes in the Night Eating Symptom Scale (NESS), the number of nocturnal awakenings and ingestions, total daily calorie intake after the evening meal, Clinical Global Impression of Severity Scale (CGI-S), Quality of Life Enjoyment and Satisfaction Scale (Q-LES), and weight. Results: Sertraline was associated with statistically significantly greater improvements than placebo in the CGI-I scale. As determined by a CGI-I score of ≤2 (much or very much improved), 12 subjects in the sertraline group (71%) were classified as responders versus only 3 in the placebo group (18%). There were also significant improvements in the NESS, CGI-S scales, Q-LES, frequency of nocturnal ingestions and awakenings, and calorie intake after supper. Overweight and obese subjects in the sertraline group (n = 14) lost a significant amount of weight by week 8 (mean = −2.9, SD = 3.8 kg) compared to those in the placebo arm (n = 13) (mean = −0.3, SD = 2.7 kg). Conclusions: In this 8-week trial, sertraline was effective in the treatment of NES and was well tolerated.