Eating late changes your fat tissue and decreases calories burned

New research provides experimental evidence that eating late reduces energy expenditure, increases hunger and alters fatty tissue, 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 eating mantras warn against midnight snacking, few studies have thoroughly investigated the combined impacts of late meals on the three key factors in regulating body weight and therefore risk of heart disease. obesity: the regulation of calorie intake, calorie burning and molecular changes in fatty tissue.

Researchers at Brigham and Women’s Hospital, a founding institution of the Mass General Brigham Health System, found in a recent study that the timing of meals has a significant impact on our energy expenditure, appetite, and molecular pathways in adipose tissue. Their findings were recently published in the journal Cell 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 Sleep and Disorders. circadians. “Previous research by us and others has shown that eating late is associated with an increased risk of obesity, increased body fat and reduced weight loss. We wanted to understand why.

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

A total of 16 people with an overweight or obese body mass index (BMI) were examined by Vujovi, Scheer and their colleagues. Each participant followed two lab protocols: one with a rigidly planned early meal schedule and the other with exactly the same meals, each set about four hours later in the day.

Participants maintained set sleeping and waking times for the last two to three weeks before starting each of the protocols in the lab, and they 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, small frequent blood draws throughout the day, and regularly recorded their hunger and appetite.

To measure how time to eat affected molecular pathways involved in adipogenesis, or how the body stores fat, researchers collected adipose tissue biopsies from a subset of participants during lab tests in the protocols. early and late feeding, to allow comparison of gene expression patterns 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 desire to eat. Specifically, levels of the hormone leptin, which signals satiety, decreased over 24 hours in the late feeding conditions compared to the early feeding conditions. When participants ate later, they also burned calories at a slower rate and showed adipose tissue gene expression toward increased adipogenesis and decreased lipolysis, which promote fat growth. In particular, these results reflect convergent 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. By using a randomized crossover design and tightly controlling behavioral and environmental factors such as physical activity, posture, sleep, and light exposure, researchers were able to detect changes in the various control systems involved in energy balance, a marker of how 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 larger population. Although this study cohort only included five participants, the study was designed to control the menstrual phase, which reduces confounding but makes recruiting women more difficult. Going forward, Scheer and Vujović also want to better understand the effects of the relationship between mealtime and bedtime on energy balance.

“This study shows the impact of late eating compared to early eating. Here, we isolated these effects by controlling for confounding variables such as calorie intake, physical activity, sleep, and exposure to light, but in real life many of these factors may themselves be influenced by mealtimes,” Scheer said. “In larger-scale studies, where tight control of all these factors is not If not, we need to at least consider how other behavioral and environmental variables alter these biological pathways underlying obesity risk. ”

Reference: “Late isocaloric feeding increases hunger, decreases energy expenditure, and alters 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, Martha Garaulet, Matthew J. Brady, and Frank AJL Scheer, October 4 Cell metabolism.
DOI: 10.1016/j.cmet.2022.09.007

The study was funded by the National Institutes of Health, the Spanish Government of Investigation, 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 lecture fees from Bayer HealthCare, Sentara HealthCare, Philips, Vanda Pharmaceuticals, and Pfizer Pharmaceuticals; received consulting fees from the University of Alabama at Birmingham; and served on the board of the Sleep Research Society. Scheer’s interests have been considered and managed by Brigham and Women’s Hospital and Partners HealthCare in accordance with their conflict of interest policies. None of these are related to work in progress. Vujović was compensated for consultancy services provided to the Novartis Institutes for Biomedical Research, also unrelated to ongoing work.