Sleep and Body Weight: A Close Relationship

“If you weigh too much, maybe you should try sleeping more.”

This commentary in the journal Sleep caught my eye. Flip as it sounds to a person who would sleep more if she could, it points to a relationship between sleep and body weight that should be widely publicized.

Sleep can also affect your ability to keep weight off. As for the relationship between insomnia and body weight, the latest news is surprising. Read on for details:

Insomnia with short sleep increases susceptibility to overweight“If you weigh too much, maybe you should try sleeping more.”

This commentary in the journal Sleep caught my eye. Flip as it sounds to a person who would sleep more if she could, it points to a relationship between sleep and body weight that should be widely publicized.

Sleep can also affect your ability to keep weight off. As for the relationship between insomnia and body weight, the latest news is surprising. Read on for details:

Sleep Deprivation and Weight Gain

It’s established now that sleep deprivation increases feelings of hunger (or interferes with feelings of satiation). Sleep deprivation occurs when sleep is arbitrarily restricted—as it might be during a research project in a sleep lab, when participants’ sleep is restricted to 4 hours a night—or when work or family responsibilities keep you from getting the sleep you need. Either way, the tendency is to eat more. And the more you eat, the more weight you gain.

People who are chronically sleep deprived don’t only tend to put on weight. They also risk developing metabolic syndrome, which is linked to serious medical problems like heart disease and diabetes.

So if the bathroom scale is inching upward every time you weigh yourself, consider not just changes to diet and exercise but also allowing more time for sleep if—and this an important caveat—you’re actually able to get more sleep. A mere 30 minutes more sleep a night can help with weight loss and greatly improve your long-term health.

Short Sleep and Body Weight

People who are short sleepers by nature—those who routinely sleep less (sometimes quite a bit less) than 6 hours a night—are also more susceptible to weight gain and obesity than those whose nights are longer. A study conducted over a period of 13 years showed that every extra hour of sleep duration was associated with a 50% reduction in risk of obesity.

Short sleep is also associated with impaired glucose tolerance and insulin resistance. Thus short sleepers are more at risk for developing diabetes as well.

Sleep Duration Is Not the Whole Story

But routinely shortened sleep is not the only sleep issue associated with weight problems. Research is showing now that sleep quality is related to the ability to lose weight and keep it off.

Unlike sleep duration, which can be objectively measured with polysomnography, sleep quality cannot be assessed objectively. So it’s typically measured with questions similar to these:

  • Do you regularly have trouble sleeping?
  • What’s the overall quality of your sleep?
  • How often do you experience a sense of well-being during the day?

One recent study found that better sleep quality and being a “morning person” correlated with successful weight loss maintenance. Compared with current enrollees in a weight loss program, people who’d lost at least 30 pounds and kept the weight off for at least a year reported significantly better sleep quality and were more often early risers.

In another study, investigators compared people who maintained a loss of at least 10% of their body weight to people who regained their lost weight. Men (but not women) who were successful at shedding pounds and keeping them off reported significantly better sleep quality (but not more sleep) than the weight regainers.

Do Insomniacs Typically Have Weight Problems?

Not necessarily, if results of the latest study can be believed. Researchers in Germany compared the body mass index (BMI) of 233 patients with “severe and chronic insomnia . . . showing objectively impaired sleep quality” to the BMI of 233 age- and gender-matched good sleepers. The results were surprising:

  • BMI, insomniacs: 23.8 kg/m2 (The “normal” BMI range is 18.5 to 24.9.)
  • BMI, good sleepers: 27.1 kg/m2

On average, the chronic insomniacs weighed significantly less than the good sleepers. If confirmed by other research, the result should be somewhat reassuring to those of us concerned about the consequences of insomnia. It would also lend support to the idea that insomnia has less to do with insufficient sleep than with excessive arousal (or hyperarousal) that may affect us 24/7.

Do you find yourself eating more after a couple bad nights?

Is Short Sleep an Inborn Trait?

We’re often warned about getting less than 7 to 8 hours of sleep a night. Short sleepers—variously defined as people who sleep 5 hours and less or less than 6—are more susceptible than normal sleepers to a host of problems: cardiovascular disease, obesity, diabetes, cancer, and dementia. Many people with insomnia fall within that 5- to 6-hour range. Rarely do we get encouraging news about our prospects for a healthy life.

But recent research on genetic mutations tells a different story. Not only does it begin to explain some of the differences in sleep duration among human beings. It also suggests that short sleep may not necessarily have adverse effects on our health and quality of life.

Sleep differences in fraternal twins may occur due to different DNA sequencingWe’re often warned about getting less than 7 to 8 hours of sleep a night. Short sleepers—variously defined as people who sleep 5 hours and less or less than 6—are more susceptible than normal sleepers to a host of problems: cardiovascular disease, obesity, diabetes, cancer, and dementia. Many people with insomnia get just 5 or 6 hours of sleep a night. Rarely do we get encouraging news about our prospects for a healthy life.

But recent research on genetic mutations tells a different story. Not only does it begin to explain some of the differences in sleep duration among human beings. It also suggests that short sleep may not necessarily have adverse effects on our health and quality of life.

Short Sleep but Not Insomnia

One of these studies was published in the journal Science in 2009. In it, investigators were looking at the DNA sequences of people who naturally tended to wake up early. They located a genetic mutation in a mother and daughter who typically slept 6 to 6½ hours a night.

The women’s nights were consistently shorter than the nights of other members of their family, who did not have the mutation and who slept about 8 hours. Yet they woke up feeling well rested in the morning, with no sign of insomnia at night or fatigue during the day.

The mutation occurred in a protein (known as BHLHE41) in which one amino acid was substituted for another. This genetic variant did not interact in the usual way with nearby genes controlling circadian rhythms. So the expectation might be that this variant would have some effect on the timing of sleep, and it did. The mother and daughter were early awakeners. But it also affected the duration of their sleep, predisposing them to shorter sleep.

More Genetic Variants

Then in August 2014 another team of researchers, examining the DNA sequencing in twins and unrelated subjects, announced the discovery of 2 new genetic variants of the same protein, BHLHE41. These researchers were looking for genetic factors in humans that confer resistance to sleep loss. One of the 2 variants they identified had a big impact on both sleep and performance after sleep deprivation.

The carrier of the novel variant was a 27-year-old man whose fraternal twin, also male, did not have the mutation. The sleep-related differences between the twins were fascinating:

  1. The carrier twin slept an average of 5 hours a night—over an hour less than his brother.
  2. Despite his shorter nights, the carrier had a similar amount of nonrapid eye movement sleep (NREM sleep) as his twin. NREM sleep is composed of light sleep and deep sleep, which is associated with restorative processes.
  3. After going 38 hours without any sleep at all, the carrier twin slept 8 hours while his brother slept 9½. Yet an analysis of brainwaves showed that the carrier had higher delta power during NREM sleep, suggesting greater sleep drive.

Response to Sleep Deprivation

The brothers’ response to sleep loss was fascinating, too. After a full night without sleep, they underwent standardized testing every 2 hours to measure their cognitive vulnerability to sleep deprivation.

It wasn’t the more normal sleeper who fared better on the tests. It was the short sleeper—the carrier of the mutation—who had “significantly fewer average lapses of performance” on the tests. Based on these results and results of other studies, the researchers conclude that this novel variant of the BHLHE41 is associated both with short sleep and resistance to the effects of sleep loss.

Whether it also protects people from the health problems linked to short sleep remains to be seen. But regarding obesity, the study is reassuring. The body mass index (BMI) of the noncarrier twin was on the heavy side of “healthy,” but the carrier’s BMI was well within the healthy range.

We hear a lot about the problems associated with short sleep. But occasionally some bit of research comes along showing that our prospects for healthy lives may not be so bad after all.

Eat Right to Sleep Tight

In the late Renaissance, many medical authorities were convinced that digestive processes controlled the duration of sleep. People slept as long as necessary to digest their evening meal.

That proposition fell by the wayside long ago—yet new evidence suggests that the timing of meals does affect our sleep. Particularly in people who are prone to insomnia, eating more regular meals, and eating dinner earlier in the evening, may be important keys to sounder sleep and good health.

Eating irregular meals, and iron-high snacks at night, is harmful to sleep and healthIn the late Renaissance, many medical authorities were convinced that digestive processes controlled the duration of sleep. People slept as long as necessary to digest their evening meal.

That proposition fell by the wayside long ago—yet new evidence suggests that the timing of meals does affect our sleep. Particularly in people prone to insomnia, eating regular meals, and eating dinner earlier in the evening, may be important keys to sounder sleep and good health.

In Sync

Regularity is a familiar theme to people with insomnia. “Go to bed and get up at the same time every day,” we hear again and again.

Good sleepers tend to do this naturally. Their stable, high quality sleep is a sign that their internal circadian rhythms are all synched up. These rhythms are established by the body clock, which hews to a 24-hour cycle with daily exposure to sunlight.

People with insomnia are not so regular about sleep. Over a two-week period, the authors of a study of daily activities and sleep found, insomnia subjects had over an hour of daily variability in when they went to bed and got up in the morning. This variability could throw their internal rhythms out of whack and lead to symptoms of insomnia.

But compared with normal sleepers, the insomniacs were also more variable in when they had meals and snacks. For them, lunch could vary by as many as 3 hours from one day to the next. The timing of their evening snacks had a range of almost 3 hours as well.

A Relationship between Eating and Sleeping         

Sunlight is not the only thing that keeps our circadian rhythms synched up. In addition to the master clock in the brain, which is set by the sun, many peripheral clocks are spread throughout our bodies. Some of them are sensitive to the timing of meals. Eating at odd hours disrupts their rhythm. Circadian rhythms are then thrown out of sync, and this invites insomnia.

“This finding highlights the potential importance of regular mealtimes,” the authors state. “Perhaps incorporating a regular meal schedule into treatment for those with insomnia could help to align the internal clock with a 24-hour light/dark cycle, which would contribute to healthier sleep.”

Avoid Iron-Rich Foods at Night

Another study suggests that eating foods high in iron at night is harmful to health. Not only does it alter circadian rhythms, but it may also increase our vulnerability to obesity, diabetes and other metabolic disorders.

This study was conducted on mice. One of the many peripheral clocks in mice and humans is located in the liver, an organ that regulates blood glucose levels. In this study, scientists found that dietary iron establishes the circadian rhythm of the liver.

Eating iron-rich foods during the daytime is healthy. Metabolic processes that ensue after a meal high in meat, beans, leafy green vegetables or dried fruit are not harmful when they occur in sync with the body’s natural rhythms.

But feeding iron to mice at a time when they would normally be asleep resulted in the clock in the liver going out of sync with the body clock in the brain, and a dysregulation of blood glucose levels. Particularly in shift workers, said investigators in ScienceDaily, eating foods high in iron at night could lead to obesity, diabetes and other metabolic disorders.

So if you’re a poor sleeper or prone to raiding the fridge at midnight, aim for regular meals and lighter midnight snacks.

What foods do you typically eat when you can’t sleep?

 

Sleep Deprived and Gaining Weight

When I’m stressed out, two things happen. One, sleep goes on the lam, and two, I eat to compensate. Last night it was an ice cream cone at Stucchi’s. The night before, I opened a honey jar and had some honey straight up. Move over, Winnie the Pooh!

Sweets and fat are irresistible when I’m feeling sleep deprived, and a new study from UPenn suggests I’m far from abnormal in that regard. The particulars are alarming, so read on.

Eating-Honey2Preparing for a book launch can be stressful, and when I’m stressed out, two things happen. One, sleep goes on the lam, and two, I eat to compensate. Last night it was an ice cream cone at Stucchi’s. The night before, I opened a honey jar and had some honey straight up. Move over, Winnie the Pooh!

Sweets and fat are irresistible when I’m feeling sleep deprived, and a new study from UPenn suggests I’m far from abnormal in that regard. In this study, just five nights of sleep restriction led to a significantly higher intake of calories and weight gain among subjects who were allowed to spend only four hours a night in bed. Short sleep and weight gain apparently go hand in hand.

The particulars are alarming, so read on.

Sleep Restriction Experiment

Researchers monitored 225 subjects—male and female, African American and Caucasian—in a sleep lab for five days. At night, the 27 control subjects could sleep as long as they wished. The other 198 subjects were only allowed to sleep between 4 and 8 a.m. While awake, the subjects spent their time reading, watching TV, and playing video and board games. Exercise was not allowed. Food was available at all times except during testing. Subjects could eat what and when they wanted.

Results

After just five days of sleep restriction,

  • Sleep-restricted subjects gained an average of two pounds, while controls gained a few ounces.
  • Among the sleep-restricted subjects, weight gain was highest among African-American males and lowest among Caucasian females.
  • Sleep-restricted subjects consumed 30 percent more calories than control subjects.
  • Consumption of the extra calories occurred between 10 p.m. and 4 a.m.

The Take-Away

A chronically sleep-deprived lifestyle—particularly one where you have to stay up late at night—sets you up for being overweight. If just five nights of sleep restriction result in a gain of two pounds, what will months and months of short sleep do?

Fortunately my bouts of stress-induced insomnia are rarer than they used to be, so most of the time I’m eating lots of fruit, veggies, fish, and whole grains rather than honey and ice cream. Still, the food cravings I get after just a couple nights of short sleep are so marked that I can’t help but wonder: how much of America’s obesity epidemic is due to poor and insufficient sleep?

What foods are you drawn to when you feel sleep deprived?

The Sleepy Teen Problem

The thinking on teen sleepiness is getting complicated these days. On one hand, there’s reason to believe that American teens should get more sleep than they actually do.

On the other hand, a new review of literature published this month in the journal Sleep suggests the issue of children’s sleep need is far from settled.

sleepy-teenGot a sleepy adolescent who’s up texting at night and then dead to the world in the morning?

It seems like a no-brainer that teenagers who drift through breakfast like zombies should be getting more sleep, right? And the solution is equally obvious: confiscate their cell phones, turn off their computers, enforce a lights-out policy at 10 p.m. How else are they going to get the eight-and-a-half to ten hours recommended by venerable institutions like Harvard University and the National Heart, Lung, and Blood Institute?

But not so fast. The thinking on teen sleepiness is getting complicated these days. On one hand, there’s reason to believe that American teens should get more sleep than they actually do, say researchers at the University of Pennsylvania. Released this week, their findings suggest that increasing sleep duration to 10 hours a night could help cut down on adolescent obesity.

Recommended Sleep Times: Are They Valid?

On the other hand, a new review of literature published this month in the journal Sleep suggests the issue of children’s sleep need is far from settled. Consider, for instance, this fascinating factoid: at any given age, children from Asia sleep

  • 60 to 120 minutes less than children in Europe, and
  • 40 to 60 minutes less than children in the United States.

Not only do Asian children get less sleep, but they also report needing less sleep than their European and American counterparts. What to make of this huge discrepancy? Are children’s sleep needs determined by genetic differences or sociocultural context? Are Asian children catastrophically sleep-deprived?

The upshot of this review is that any recommendations you’ve ever heard about the sleep needs of teenagers are speculative and based on inadequate data, a fact which, in the words of sleep investigator Irwin Feinberg, “embarrasses our field.”

Feinberg, in an accompanying editorial, acknowledges that daytime sleepiness among adolescents is a major public health concern. Yet spending more time in bed may not help.

Changes in the Adolescent Brain

The human brain undergoes a major reorganization during adolescence, says Feinberg, and this reorganization has a dramatic effect on teenagers’ brains at night. Young children get lots of deep sleep. But the proportion of deep sleep children get begins to decline in early adolescence, and this is strongly related to an increase in daytime sleepiness.

Adolescence also brings a steep decline in a lighter stage of sleep characterized by theta brainwaves, says Feinberg, and that this decline correlates even more strongly with the steep rise in sleepiness in children as they move through their teenage years.

But here’s the kicker: the decrease in theta waves and the corresponding rise in sleepiness occur independent of how long teens sleep or how many hours they stay in bed.

So is there a solution for adolescents who can barely get dressed in time to catch the bus? Later starting times at middle and high schools may be part of the answer. As for the rest, it’s wait and see.

If you’ve got a sleepy teenager (or if you ever had one), what ways have you found to combat the problem?

Sleep and Adolescent Obesity

Insufficient Evidence on Children’s Sleep Needs

Sleep Problems and Weight Gain

I get a serious case of the munchies when I’m feeling sleep-deprived. A few short nights is all it takes to propel me to the places where the good stuff is. I break into the chocolate, corn chips, cheese, and salted nuts with the zeal of a wild pig rooting for truffles, and I eat and eat.

insomnia leading to sleep loss ups your chances of obesityI get a serious case of the munchies when I’m feeling sleep-deprived. A few short nights is all it takes to propel me to the places where the good stuff is. I break into the chocolate, corn chips, cheese, and salted nuts with the zeal of a wild pig rooting for truffles, and I eat and eat.

This reaction to feeling short on sleep is not uncommon, I discovered while conducting interviews for my book. Several insomnia sufferers talked of compensating for lack of energy by overeating and indulging in high-fat comfort foods. Pat, whose high-stress job as a lawyer routinely shortened his nights, felt there was a direct relationship between his insomnia and his weight.

“I’m someone who most of my adult life has been heavier than I want to be,” he said. “When you’re always tired, it’s easier to stress out and harder to be disciplined about eating and working out.”

What the Studies Say

Lots of evidence now links short sleep duration to weight gain and the development of metabolic syndrome (which leads to conditions such as heart disease and diabetes). Research affirms a relationship between sleep deprivation and overeating as well. A recent meta-analysis of the literature on lifestyle factors affecting the drive to eat found that alcohol consumption, sleep deprivation and TV watching significantly increased the short-term drive to eat.*

Another new study suggests that the hormonal factors involved in the increased drive to eat following short sleep may be different in men and women.** Researchers found that restricting subjects’ sleep to 4 hours a night for 3 nights led to

  • increased levels of ghrelin in the men but not the women. Ghrelin is a hunger-stimulating hormone produced in the stomach and the pancreas.
  • reduced levels of GLP-1 in the women but not the men. Produced in the intestine, GLP-1 is a satiety hormone whose levels increase with the eating of meals.

So the men’s response to sleep restriction was to have bigger appetites, and the women’s response was to feel less full. But whether you’re ravenous from the get-go or find it hard to stop eating once you’ve begun, the result is often weight gain and all its unwelcome consequences.

The obesity epidemic today gets blamed on dietary, socioeconomic, environmental, and genetic factors, and lack of exercise. I think more effort ought to go toward exploring the relationship between weight gain and short sleep.