Obesity is already a massive problem in America, no pun intended. The Centers for Disease Control and Prevention reports that over 40 percent of U.S. adults are obese and that this contributes to the growing rash of diabetes, cancer and other chronic conditions among the population.
Unfortunately, late-night snacking is only making the obesity problem worse. It’s not just the extra calories that after-hours snacking brings to the widening of America. Boston’s Brigham and Women’s Hospital reports that this eating habit increases a person’s hunger, decreases the calorie burn and alters an individual’s fat tissues.
Sage wisdom, of course, has long advised against late-night nibbles. The Boston-based research, however, is significant because it is one of the few studies to examine the exact impact of when a person eats on their fat composition.
“We wanted to test the mechanisms that may explain why late eating increases obesity risk,” reported senior author Frank A. J. L. Scheer, Director of the Medical Chronobiology Program at Brigham. “Previous research by us and others had shown that late eating is associated with increased obesity risk and body fat and impaired weight loss success. We wanted to understand why.”
The study examined whether timing matters when everything else is consistent, first author Nina Vujovic added. “And we found that eating four hours later makes a significant difference for our hunger levels, the way we burn calories after we eat, and the way we store fat,” she reported.
The research team studied 16 patients with a body mass index (BMI) in the overweight or obese range. Each participant followed two laboratory protocols: one with a strictly scheduled early meals and the other with the same meals about four hours later in the day. The participants regularly documented their hunger and appetite and provided frequent small blood samples throughout the day. They also had their body temperature and energy expenditure measured. In addition, researchers collected biopsies of adipose tissue from participants to measure how eating time affected molecular pathways involved in adipogenesis–how the body stores fat.
Results revealed that eating later had profound effects on hunger and appetite-regulating hormones leptin and ghrelin, which influence a person’s drive to eat. When participants munched later, they also burned calories slower. They exhibited increased adipogenesis and decreased lipolysis, which promotes fat growth.
The findings supported the notion that eating later may promote obesity and why this occurs.
“This study shows the impact of late versus early eating. Here, we isolated these effects by controlling for confounding variables like caloric intake, physical activity, sleep, and light exposure. But in real life, many of these factors may themselves be influenced by meal timing,” said Scheer. “In larger scale studies, where tight control of all these factors is not feasible, we must at least consider how other behavioral and environmental variables alter these biological pathways underlying obesity risk. ”