Exploring the impact of meal timing on health and metabolism

Accumulating evidence on the impact of mealtimes on circadian rhythms and metabolism makes it clear that the time we eat can impact our overall health and wellbeing. Special Issue Journal of the Academy of Nutrition (JundThe Elsevier publication Chronnutrition (Chrononutrition) reviews the effects of various fasting regimens and covers safety considerations and practical guidance.

The field of chrononutrition is gaining attention as it explores the relationship between temporal eating patterns, circadian rhythms, and metabolism for optimal health.

Guest Editor Krista Varady, PhD (Department of Kinesiology and Nutrition, University of Illinois at Chicago), specializes in the study of the effectiveness of intermittent fasting for weight loss, weight management, and reducing the risk of metabolic disease in obese adults. With over 15 years of research experience, she is recognized as one of the top researchers in her field.

Dr Varady says: “Intermittent fasting has emerged in recent years as one of the most popular diets for weight loss. This diet can essentially be defined as alternating periods of eating and fasting. This special issue examines the effects of different fasting methods, including time-restricted eating, alternate-day fasting, and the 5:2 diet, on subjects’ weight, risk of cardiometabolic disease, sleep, and exercise capacity. Appropriate safety considerations and practical guidance for the application of the diets are also covered.”

Editor-in-chief JundAdded Linda G. Snetzeler, PhD, RDN, FAND, LD, professor of epidemiology at the University of Iowa: “The findings published in this special issue have important clinical implications. As we address dietary interventions related to chronic disease risk factors, meal timing will become increasingly important.”

This special issue features a novel study, “A Randomized Controlled Trial of Late 8-Hour Time-Restricted Eating in Adolescents with Type 2 Diabetes,” in which researchers investigate the feasibility of eating within an 8-hour window compared with a longer eating window as an intervention strategy for weight loss and glycemic control in adolescents diagnosed with obesity and new-onset type 2 diabetes.

“The study is a first-of-its-kind trial that has shown that 100% of patients with pulmonary circulation suffer from pulmonary circulation problems,” explained lead researcher Alaina P. Vidmer, MD, PhD, of Children’s Hospital Los Angeles and the Keck School of Medicine of the University of Southern California. “The prevalence of type 2 diabetes in adolescents has been steadily increasing, especially in historically marginalized communities. Because many adolescents have later bedtimes and prefer to sleep until later in the morning, early feeding may not align with developmental and social schedules that often shift food intake to later times. We trialed late feeding in our cohort and found that late feeding was safe and tolerable for this subset of adolescents, potentially leading to clinically meaningful weight loss, lower alanine transaminase, and significant calorie reductions. There were no adverse effects on sleep, eating behaviors, or physical activity.”

The other paper, “Sleep health indicators are associated with timing and duration of eating habits in young adults,” details the results of a cross-sectional study of 52 young adults without any chronic diseases or conditions that investigated whether the timing and duration of eating behaviors throughout the day influence sleep health.

“These findings are a step toward a more effective treatment for chronic conditions,” said Dr. Jess A. Gwinn, principal investigator for the Military Nutrition Division of the U.S. Army Research Institute of Environmental Medicine. “Skipping breakfast and eating at night are common eating habits among young people in the United States. Our study found that meal timing was associated with sleep-wake onset and sleep efficiency, highlighting the need for additional research to understand whether manipulating meal timing to align with the sleep-wake cycle can improve sleep health.”

According to the article, “Time-restricted Eating in Community-Dwelling Adults: Correlates of Adherence and Cessation in a Cross-Sectional Online Survey Study,” interventions tailored to individual preferences and circumstances may be beneficial for improving adherence to time-restricted eating. “The study was led by research team leader Dr. Sidney G. O’Connor of the National Institutes of Health’s Department of Behavioral and Social Sciences,” he said. “Adherence to a diet is the strongest predictor of successful weight loss and maintenance; therefore, identifying diet strategies that promote adherence is a priority in the field of behavioral weight management. We considered motivating factors such as weight maintenance, health (rather than weight), improved sleep, and disease prevention as well as contributing factors such as the ability to work from home and the impact of COVID-19.”

Dr Varady concludes:“Many people become frustrated by having to monitor their food intake regularly each day and stop adhering to standard calorie-restricting diets. Intermittent fasting protocols can circumvent this requirement while still achieving weight loss by allowing participants to simply ‘watch the clock’ instead of monitoring calories. Furthermore, intermittent fasting avoids the need to purchase expensive foods and allows individuals to continue eating foods they are familiar with, making it a very accessible dietary regimen, especially for low-resource patient groups. Although fasting regimens are not more effective than other dietary interventions for weight management, by eliminating the need for calorie counting, these protocols offer individuals an alternative, simple way to address obesity.” Although losing weight is important, the most important part of maintaining good nutrition is to include a variety of nutritious foods in your diet, such as fruits, vegetables, and legumes. These foods can be inexpensive and culturally appropriate.“