By John Salak –
Late-night munching is a habit that so many people embrace, whether it involves grabbing some midnight cookies, chips or a second slice of that blueberry pie that is just sitting on the counter begging to the gobbled.
It may seem like a good idea at the time, but it’s not, and a recent study by Brigham and Women’s Hospital proves it. The study claims decreased energy expenditure, increased hunger, and changes in fat tissue, increasing obesity risk.
Since more than 40 percent of U.S. adults are obese, which contributes to diseases like diabetes and cancer, learning to fight the urge to munch late is pretty important.
Brigham and Women’s Hospital isn’t the first group or person to warn against these ill-timed snacks. But until now, there was no scientific backing on why this may occur, which fueled the reason for conducting this latest research.
“We wanted to test the mechanisms that may explain why late eating increases obesity risk,” explained senior author Frank A. J. L. Scheer. “Previous research by us and others had shown that late eating is associated with increased obesity risk, body fat, and impaired weight loss success. We wanted to understand why.”
The research also wanted to examine if other factors came into play for late-night eating. “In this study, we asked, ‘Does the time that we eat matter when everything else is kept consistent?’” noted first author Nina Vujovic. “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.”
The research focused on studying 16 patients with a body mass index (BMI) in the overweight or obese range. Each participant completed two laboratory protocols: one with strictly scheduled early meals and the other with the same meals about four hours later in the day.
The initial process was direct enough. However, measuring how eating time affected how the body stores face required investigators to collect biopsies of adipose tissue from a subset of participants during laboratory testing in both the early and late eating protocols. It allowed them to compare gene expression patterns between the two eating conditions.
Results revealed that eating later had profound effects on hunger and appetite-regulating hormones leptin and ghrelin, which influences an individual’s eating drives. Participants who ate later also burned calories slower. They exhibited increased adipogenesis and decreased lipolysis, which promotes fat growth.
“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. In real life, many of these factors may themselves be influenced by meal timing,” said Scheer.
Eliminating late eating for individuals involved in traditional routines may seem logical. It is important for shift workers, whose jobs require them to have late-night routines and have meals at unusual hours.
The NIH/National Heart, Lung and Blood Institute reports that eating only during the daytime might prevent the higher glucose levels now linked with nocturnal work life.
The findings could lead to novel behavioral interventions aimed at improving the health of shift workers—grocery stockers, hotel workers, truck drivers, and first responders, among others—who past studies show may be at an increased risk for diabetes, heart disease and obesity.
“This is a rigorous and highly controlled laboratory study that demonstrates a potential intervention for the adverse metabolic effects associated with shift work, which is a known public health concern,” reported Marishka Brown, director of the NHLBI’s National Center on Sleep Disorders Research.
The study examined 19 healthy young participants randomly assigned to a 14-day controlled laboratory protocol involving simulated night work conditions with one of two meal schedules. Researchers then evaluated the effects of these meal schedules on their internal circadian rhythms, which regulate the sleep-wake cycle and other bodily functions, including metabolism.
The researchers found that nighttime eating boosted glucose levels by 6.4 percent, which increases the risk of diabetes. Those who ate only daytime meals showed no significant increase in glucose.
“This is the first study in humans to demonstrate the use of meal timing as a countermeasure against the combined negative effects of impaired glucose tolerance and disrupted alignment of circadian rhythms resulting from simulated night work,” reported study leader Frank A.J.L. Scheer.
“This study reinforces the notion that when you eat matters for determining health outcomes such as blood sugar levels, which are relevant for night workers as they typically eat at night while on shift,” noted the study co-leader Sarah L. Chellappa.