Effect of Sleep Deprivation

"Sleep loss boosts hunger and unhealthy food choices" Review

Could the secret to weight loss actually be lying in your bed...literally? In the recent study conducted by University of Chicago, researchers have found that a lack of sleep actually releases a chemical signal that enhances the pleasure experienced while eating unhealthy food. Here is the writeup on the findings.

Skimping on sleep has long been associated with overeating, poor food choices and weight gain. Now a new study shows how sleep loss initiates this process, amplifying and extending blood levels of a chemical signal that enhances the joy of eating, particularly the guilty pleasures gained from sweet or salty, high-fat snacks.

The findings were published Feb. 29 in the journal SLEEP.

Sleep-deprived participants in this study—all young, healthy volunteers—were unable to resist what the researchers called “highly palatable, rewarding snacks,” meaning cookies, candy and chips, even though they had consumed a meal that supplied 90 percent of their daily caloric needs two hours before. The effects of sleep loss on appetite were most powerful in the late afternoon and early evening, times when snacking has been linked to weight gain.

“We found that sleep restriction boosts a signal that may increase the hedonic aspect of food intake, the pleasure and satisfaction gained from eating,” said Erin Hanlon, a UChicago research associate in endocrinology, diabetes and metabolism. “Sleep restriction seems to augment the endocannabinoid system, the same system targeted by the active ingredient of marijuana, to enhance the desire for food intake.”

This chemical signal is the endocannabinoid 2-arachidonoylglycerol (2-AG). Blood levels of 2-AG are typically low overnight. They slowly rise during the day, peaking in the early afternoon.

When the study subjects were sleep-deprived, however, endocannabinoid levels rose higher and remained elevated through the evening, beyond the typical 12:30 p.m. peak. During that period, sleep-restricted study subjects reported higher scores for hunger and a stronger desire to eat. When given access to snacks, they ate nearly twice as much fat as when they had slept for eight hours.

This increase in circulating endocannabinoid levels, the authors note, “could be a mechanism by which recurrent sleep restriction results in excessive food intake, particularly in the form of snacks, despite minimal increases in energy need.”

“The energy costs of staying awake a few extra hours seem to be modest,” explained Hanlon. “One study has reported that each added hour of wakefulness uses about 17 extra calories. That adds up to about 70 calories for the four hours of lost sleep. But, given the opportunity, the subjects in this study more than made up for it by bingeing on snacks, taking in more than 300 extra calories. Over time, that can cause significant weight gain.”


Obesity and sleep restriction have become extremely common. According to the Centers for Disease Control and Prevention, about a third of Americans get less than seven hours of sleep a night and more than a third of adults in the United States are obese. A 2013 Gallup poll found that U.S. adults sleep an average of 6.8 hours per night. Forty percent of adults report sleeping six hours or less.

Hanlon and colleagues designed the study to help understand how the endocannabinoid system connected short sleep with weight gain. Her team recruited 14 healthy men and women in their 20s as volunteers. The researchers monitored the subjects’ hunger and eating habits in two situations: one four-day stay in the University’s Clinical Research Center, during which they spent 8.5 hours in bed each night (averaging 7.5 hours of sleep), and another four-day stay when they spent only 4.5 hours in bed (4.2 hours asleep).

The participants ate identical meals three times a day—at 9 a.m., 2 p.m. and 7 p.m. Researchers measured levels of the hormone ghrelin, which boosts appetite, and leptin, which signals fullness, in their blood. Previous studies have linked high ghrelin and low leptin levels to reduced sleep time and increased appetite.

For the first time, however, they also measured blood levels of endocannabinoids. After a normal night’s sleep, 2-AG levels were low in the morning. They peaked in the early afternoon, soon after lunchtime, then decreased.

After restricted sleep, however, 2-AG levels rose to levels about 33 percent higher than those seen after normal sleep. They also peaked about 90 minutes later, at 2 p.m., and remained elevated until about 9 p.m.

After the period of restricted sleep, study subjects reported a significant increase in hunger levels. This was prominent soon after their second meal of the day, the time when 2-AG levels were highest. Sleep deprived study subjects expressed greater desire to eat. When asked, they estimated that they could eat much more than they predicted the day after a full night’s sleep.

After the fourth night of restricted sleep, subjects were offered an array of snack foods. Despite having eaten a large meal less than two hours before being offered snacks, subjects in the restricted sleep phase of the study had trouble limiting their snack consumption. They chose foods that provided 50 percent more calories, including twice the amount of fat, as when they were completing the normal sleep phase.

These results support “the novel insight that sleep restriction leads not only to increased caloric intake,” but also to “changes in the hedonic aspects of food consumption,” wrote Frank Scheer of Harvard University’s Brigham and Women’s Hospital, in a commentary. The increase in 2-AG following sleep restriction, he added, “may be part of the mechanism by which people overeat.”

Despite the study’s limitations—small size, short duration and limited sampling frequency—the findings are clearly significant and consistent with the epidemiologic evidence, the authors note. They are also “relevant to normal life conditions.”

This tells us that “if you have a Snickers bar, and you’ve had enough sleep, you can control your natural response,” Hanlon explained. “But if you’re sleep deprived, your hedonic drive for certain foods gets stronger, and your ability to resist them may be impaired. So you are more likely to eat it. Do that again and again, and you pack on the pounds.”

The National Center for Research Resources, the Department of Defense, the Medical College of Wisconsin and the University of Chicago Institute for Translational Medicine supported this research. Additional authors were Kara Stuhr, Elizabeth Doncheck and Cecilia Hillard from the Medical College of Wisconsin, and Esra Tasali, Rachel Leproult, Harriet de Wit and Eve Van Cauter from the University of Chicago.

Is lack of sleep affecting your weight loss? Besides the amount of sleep, have you looked at other factors that affect your weight? Check out the list The 68 Best Ways to Lose Body Fat and More for belly-busting strategies.

Picture Credit: John Sherman Photography - My personal training clients often don't get enough sleep. Does this habit really lead to more unhealthy choices?

Article Credit:
Author: Michael Moody Fitness with excerpt sourced from the article "Sleep loss boosts hunger and unhealthy food choices" written by John Easton on http://news.uchicago.edu/
"Sleep loss boosts hunger and unhealthy food choices" Review
Learn how to lose weight from a personal trainer in Chicago.

The Link Between Staying Up Late And Getting Fat

Considering the constant demands in the lives of my personal training clients in Chicago, it isn't surprising that they're not getting much sleep. Unfortunately, this habit may be the main obstacle to their weight loss success. This article tells you why.


Inside the Sleep and Mood Research Clinic at the University of California, Berkeley, researchers studied how the number of hours a person sleeps may affect their weight. The findings, published in the journal Sleep, reveal how teenagers are especially susceptible to gaining weight when they regularly go to bed late.

For the study, researchers analyzed 3,300 teens’ and adults’ sleep schedules over five years and calculated that for every extra hour that teens stayed awake, they would gain about 2.1 points on their body mass index (BMI). BMI is a scale that’s used to measure a person’s body fat based on their height, weight, and gender, and ranges from underweight (less than 18.5) to morbidly obese (30 or greater). The researchers also found that teens were still susceptible to weight gain if they stayed up late and slept in later the next day. These findings held regardless of the time the teens spent exercising, or on their computers, cell phones, tablets, or other electronic devices. If they stayed up late, they were more likely to gain weight.

A person’s circadian rhythm, also known as their natural sleep cycle, regulates physiological and metabolic functions, and typically shifts to a later sleep cycle when puberty hits. For this reason, developing healthy sleep habits as a teen lays the foundation for a healthier adulthood — with regard to both a healthy sleep pattern and other aspects of wellbeing.

According to the National Sleep Foundation’s 2013 International Bedroom Poll, the amount of sleep the average person logs each night has steadily decreased over the past century. The average American sleeps only six-and-a-half hours a night during a five-day workweek. But while Americans have been skipping their sleep, their waistlines have been getting wider. In the last 30 years alone, obesity rates have quadrupled in adolescents, adding to the 34.9 percent of the country’s adult obesity population.

"Obesity is obviously growing among adolescents and adults, and there's also an epidemic of lack of sleep and later bedtime preference in teens," the study’s lead author Lauren Asarnow, a doctoral candidate at the University of California, Berkeley, told CBS News. "There's been some literature looking at the relationship [between] late bedtimes and weight gain cross-sectionally, but no one's ever looked at what happens long-term."

Scientists are just starting to grasp the extent to which human health depends on the length and quality of rest the body gets. Sleep typically takes up about a third of every person’s day, giving merit to why research on it has been gaining momentum — this began in 1993 when the National Institutes of Health opened up a branch specifically designed to study how sleep affects health on a short and long-term basis.

Teens are also more likely to engage in late night snacking. When the brain is sleep deprived, the prefrontal cortex, which controls impulses and decision making, isn’t working at full capacity, and therefore makes a person far more likely to give into cravings. “These results highlight adolescent bedtimes, not just total sleep time, as a potential target for weight management during the transition to adulthood,” Asarnow said in a press release, adding that teens who go to bed early “set their weight on a healthier course as they emerge into adulthood.”

Source: Asarnow L, et al. Sleep. 2015.

Picture Credit: blog.primalpastures.com

Article Credit:
Author: Samantha Olson at Medical Daily
The Link Between Staying Up Late And Getting Fat
Improving your sleep habits to lose weight while personal training in Chicago.