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?

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?