Eating Late Changes Your Fat Tissue and Decreases Calories Burned

New research provides experimental evidence that eating late reduces energy expenditure, increases hunger and changes adipose tissue, all of which may increase the risk of obesity.

About 42% of adults in the United States are obese, which increases the risk of developing chronic diseases, such as diabetes, cancer and other conditions. While popular healthy diet mantras caution against midnight snacking, few studies have thoroughly studied the combined impacts of late dining on the three key factors in regulating body weight and thus obesity risk: regulation of calorie intake, calorie burning, and molecular changes in fat tissue.

researchers in Brigham and Women’s Hospital, a founding institution of the Mass General Brigham Health System, found in a recent study that meal timing has a major impact on our energy expenditure, appetite, and molecular pathways in adipose tissue. His findings were recently published in the journal Cellular metabolism.

“We wanted to test the mechanisms that may explain why eating late increases the risk of obesity,” explained lead author Frank AJL Scheer, Ph.D., Director of the Medical Chronobiology Program in Brigham’s Division of Circadian and Sleep Disorders. “Previous research by us and others had shown that eating late is associated with increased risk of obesity, higher body fat, and lower weight loss success. We wanted to understand why.”

“In this study, we asked, ‘Does the time we eat matter when everything else is held constant?'” said first author Nina Vujović, Ph.D., a researcher in the Medical Chronobiology Program in the Division of Sleep and Health. of Brigham. Circadian disorders. “And we found that eating four hours later makes a significant difference in our hunger levels, the way we burn calories after eating, and the way we store fat.”

Vujovi, Scheer and their colleagues examined a total of 16 people with a body mass index (BMI) in the range of overweight or obesity. Each participant completed two laboratory protocols: one with a rigidly planned early meal schedule and the other with the exact same meals, each set for about four hours later in the day.

Participants maintained fixed sleep-wake schedules for the last two to three weeks before starting each of the protocols in the lab, and closely followed similar diets and meal times at home for the last three days before entering the lab. . In the lab, the participants underwent regular monitoring of body temperature and energy expenditure, frequent collection of small blood samples throughout the day, and regularly recorded their hunger and appetite.

To measure how timing of eating affected molecular pathways involved in adipogenesis, or how the body stores fat, the researchers collected adipose tissue biopsies from a subset of participants during laboratory tests in the early and late feeding protocols, to allow comparison of gene expression patterns/levels between these two feeding conditions.

The results revealed that eating later had profound effects on hunger and the appetite-regulating hormones leptin and ghrelin, which influence our drive to eat. Specifically, levels of the hormone leptin, which indicates satiety, were reduced over 24 hours in the late-fed condition compared to the early-fed conditions. When the participants ate later, they also burned calories at a slower rate and exhibited adipose tissue gene expression toward increased adipogenesis and decreased lipolysis, which promotes fat growth. Notably, these findings convey converging physiological and molecular mechanisms underlying the correlation between eating late and increased risk of obesity.

Vujović explains that these findings are not only consistent with a large body of research suggesting that eating later may increase the likelihood of developing obesity, but they shed new light on how this might occur. Using a randomized crossover study and strict control of environmental and behavioral factors, such as physical activity, posture, sleep, and light exposure, the researchers were able to detect changes in the different control systems involved in energy balance, a marker of how well our bodies use the food we eat.

In future studies, Scheer’s team aims to recruit more women to increase the generalizability of their findings to a broader population. Although this study cohort included only five female participants, the study was set up to control for menstrual phase, reducing confounding but making it difficult to recruit women. Going forward, Scheer and Vujović are also interested in better understanding the effects of the relationship between mealtime and bedtime on energy balance.

“This study shows the impact of eating late versus eating early. Here, we isolate these effects by controlling for confounding variables such as caloric intake, physical activity, sleep, and light exposure, but in real life, many of these factors can be influenced by meal timing,” he said. Scheer. “In larger-scale studies, where strict control of all these factors is not feasible, we should at least consider how other behavioral and environmental variables alter these biological pathways that underlie obesity risk. ”

Reference: “Late Isocaloric Feeding Increases Hunger, Decreases Energy Expenditure, and Modifies Metabolic Pathways in Overweight and Obese Adults” by Nina Vujović, Matthew J. Piron, Jingyi Qian, Sarah L. Chellappa, Arlet Nedeltcheva, David Barr , Su Wei Heng , Kayla Kerlin, Suhina Srivastav, Wei Wang, Brent Shoji, Marta Garaulet, Matthew J. Brady, and Frank AJL Scheer, October 4, 2022, Cellular metabolism.
DOI: 10.1016/j.cmet.2022.09.007

The study has been funded by the National Institutes of Health, the Research Government of Spain, the Autonomous Community of the Region of Murcia through the Seneca Foundation and the American Diabetes Association.

During the execution of this project, Scheer received speaking fees from Bayer HealthCare, Sentara HealthCare, Philips, Vanda Pharmaceuticals, and Pfizer Pharmaceuticals; he received consulting fees from the University of Alabama at Birmingham; and served on the Board of Directors of the Sleep Research Society. Scheer’s interests were reviewed and managed by Brigham and Women’s Hospital and Partners HealthCare in accordance with Scheer’s conflict of interest policies. None of these are related to the current job. Vujović has been compensated for consulting services provided to the Novartis Biomedical Research Institutes, which are also unrelated to the current job.