New research suggests that an extra hour of sleep every night could help sleep-deprived people who are overweight eat 270 fewer calories per day without even trying. Participants in the new study were not asked to restrict calories and did not even know that calorie intake was being measured for the trial, as it was done by analysis of urine samples the participants thought were being collected to measure other things. That translates to nearly nine pounds of weight loss over a year, according to the researchers behind the study, published February 7 in the journal JAMA Internal Medicine. “A decrease of 270 calories a day is tremendous. This is clinically important, and it’s also highly significant for people on weight loss programs,” says the lead author of the study, Esra Tasali, MD, an associate professor of medicine and the director of the Sleep Research Center at the University of Chicago. This study is not the first to connect sleep with eating patterns. Despite a growing body of evidence suggesting, like this new study, that adequate sleep helps people stick to a healthy diet (in terms of quantity and quality of calories consumed), sleep still doesn’t tend to be part of weight loss conversations — even those that happen between doctors and their patients. But that’s changing, says James Rowley, MD, a professor of critical care and sleep medicine at Wayne State University in Detroit. “For many years, sleep just was not considered part of the ‘equation’ so to speak,” he says. Now there is growing recognition that sleep needs to be considered as an important component of cardiovascular health, metabolic health, and exercise and eating, he explains. “It’s clear that adequate sleep is important for overall health.” He says he’s already started to recommend more sleep to aid in weight loss and weight maintenance in his own practice. And he says that this new research is an important piece of the puzzle, reinforcing the effect improved sleep quantity can have on calorie consumption.
A Single Sleep Counseling Intervention Helped People Sleep Longer
For the study, Dr. Tasali recruited 80 adults who were classified as overweight with a body mass index between 25 and 29.9. The group, with an average age of about 30, reported they regularly slept fewer than 6.5 hours per night. After two weeks of monitoring study participants’ sleep habits at home via wrist sensors, Tasali and her team divided the group into two categories: a control arm that continued with their regular sleep routine, and a study arm, which received a single one-on-one sleep counseling intervention. During the session, Tasali helped the study participants carve out a personalized sleep plan to work in an hour of extra sleep each night. Both groups then slept at home for another two weeks with wrist actigraphs recording their sleeping patterns. Seventy percent of those who received sleep counseling had full-time or part-time jobs; and for most, changing their sleep habits meant getting into bed earlier each night. Putting away phones, laptops, and other electronic devices before bedtime was another big factor that helped people in this group get that extra hour of sleep each night, Tasali says. The data showed that those who got the counseling improved their sleep, getting an extra one hour and 12 minutes more per night. They also ended up eating 270 fewer calories per day on average, with some participants recording up to 500 fewer calories consumed. Calorie intake was measured by urine samples using the doubly labeled water method, the gold-standard method of measuring energy expenditure. Among the control group, caloric intake increased by about 115 calories per day on average. About 270 to 300 calories is the equivalent of a McDonald’s cheeseburger — or a little bit less than the calories in four large eggs. It’s worth noting that at the onset, none of the study participants were actively trying to lose weight. They ate, on average, 2,655 calories per day. To make sure they weren’t influenced during the study, they were told the research was about collecting information about sleep habits and metabolism.
Longer Studies Are Needed, Researchers Say
Tasali says the findings are important for a few reasons: The research was done in a real-world setting, and not in a sleep lab, with participants maintaining their normal eating habits and sleeping in their own beds. The results were also objective, and free from self-reporting — wrist sensors recorded sleep duration, and the urine-based tests measured caloric intake. The study has its caveats, though. For starters, the duration was only two weeks. It also excluded people with sleep disorders, like sleep apnea, and those who work night shifts or rotating shift work. It’s unclear if people who are already getting enough sleep would see the same benefit. “We don’t know to what extent the habits would have been continued beyond two weeks. Longer-term studies are needed, and with more diverse populations, but it’s our general hypothesis that this intervention would apply to populations with various baseline weights and sleep duration,” she says.
The New Findings Build on Previous Evidence Linking Sleep With Eating Patterns
The extra sleep isn’t just about having one less hour to snack, according to Marie Pierre St-Onge, PhD, an associate professor of nutritional medicine and the director of the Sleep Center of Excellence at Columbia University Irving Medical Center in New York City. She says the study adds to a growing body of research that suggests sleep plays a major role in appetite, satiety, and hunger cues. Dr. St-Onge’s previous research, which she says is one of the largest studies on sleep restriction, found that people running on just four hours of sleep per night eat more the next day — to the tune of an extra 300 calories. That result is similar to the findings in the study from Tasali’s group, St-Onge says. “It’s possible that these same mechanisms are just going in reverse with sleep extension.” Other evidence suggests that sleep deprivation increases levels of ghrelin, nicknamed the “hunger hormone” because it increases food intake; and other research has shown that lack of sleep decreases levels of leptin, which is a hunger-suppressing hormone. Previous research Tasali worked on, published in the journal Obesity in January 2016 also found that sleep-deprived people had increased levels of ghrelin. Sleep-deprived people also tend to crave salty, sweet, fat-dense food, St-Onge says. The reward centers of the brain light up in response to junk food, according to previous findings. Together, this previous research and this new study bolster the notion that sleeping well should be part of a weight loss or weight maintenance plan. “If you’re trying to lose weight, it would be a bad idea to be sleep deprived,” St-Onge says. “You need to make sure you’re well rested so you can make good decisions in all aspects of your life, including what kinds of food you eat.” Tasali says she and her team hope their work will help get this message out. “We believe — hopefully — our study could be a game changer for our battle with the obesity epidemic in our society. It’s really about using sufficient sleep as a simple tool that can be really successful,” Tasali says.
