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  • "Does Lack of Sleep Cause You to Gain Weight?"

  • Is there a connection between sleep and weight gain or weight loss?

  • These next two videos will help answer that question.

  • Population studies have found short sleep duration

  • has been associated with obesity in both children and adults.

  • Observational studies can never prove cause-and-effect, though.

  • Maybe the obesity is leading to sleep loss

  • instead of the other way around.

  • Obesity can cause arthritis, acid reflux, and apnea,

  • all of which can interfere with sleep.

  • The relationship between obesity and sleep apnea,

  • where your breathing repeatedly stops and starts

  • throughout the night, may be explained by increased

  • tongue fatfat deposited inside the base of the tongue

  • that may contribute to obstructing your airway

  • when you sleep on your back.

  • The reverse causation explanation of the link between

  • obesity and inadequate sleep is bolstered by the finding

  • that weight loss interventions can improve daytime sleepiness.

  • Potential confounding factors also abound.

  • For example, people with lower socioeconomic status

  • often work less desirable hours such as rotating or overnight shifts,

  • or may live in noisier neighborhoods

  • with poorer air quality, more crime.

  • The link between inadequate sleep and obesity persists

  • after controlling for these kinds of factors,

  • but you can’t control for everything.

  • You can’t know for sure if sleep deprivation leads to weight gain

  • until you,...put it to the test.

  • Have people pull an all-nighter and they get hungrier

  • and choose larger portions.

  • Randomize people to shave even just a few hours of sleep off every night

  • and they start eating an average of 677 calories more a day

  • compared to the normal sleep control group.

  • Although individual responses vary widely,

  • anywhere from eating 813 calories less per day

  • to as many as 1,437 calories more,

  • on average, studies found sleep deprivation led people to overeat

  • by about 180 to 560 calories a day.

  • Restrict people’s sleep and they also start craving unhealthier choices

  • more snacks, more foods that are fatty and sugary.

  • Stick people in a brain scanner after staying awake all night,

  • or after few nights of four-hour sleep, and their reward pathways

  • light up brighter in response to high calorie foods.

  • Sleep deprivation bumps the levels of the chief endocannabinoid

  • in the body, the natural chemical we synthesize that binds

  • to the same receptors as the active ingredient in marijuana.

  • This may help explain the nighttime nibbling.

  • On the calories outside of the equation, some short sleepers

  • may take the extra time to exercise;

  • others will be so sleepy they exercise less.

  • The extra wakefulness may raise calorie expenditure

  • up to about 100 calories a day, but if sleep-deprived individuals

  • are overeating hundreds of calories, over time

  • sleep deprivation may end up putting thewidein wide awake.

  • With insufficient sleep inadvertently leading to such

  • higher calorie intake, it’s no surprise that 4 out of 5 studies

  • involving as few as 2–5 nights of sleep restriction

  • found an increase in body weight.

  • In other words, if you sleep less, you may gain more

  • OK, but here’s where it gets crazy.

  • Even if you control calorie intake, you still lose more fat

  • when you get more sleep.

  • Overweight subjects who normally got between

  • 6.5 to 8.5 hours of sleep a night were randomized to two weeks

  • of either 8.5 hours of sleep a night or 5.5 hours of sleep

  • on the same calorie- controlled diet.

  • Then the groups switched and spent another two weeks

  • on the opposite regimen.

  • So they spent a month living in the lab so their diets and sleep

  • could be totally controlled and monitored.

  • Just looking at the scales, sleep duration didn’t seem to matter,

  • during both periods they ate the same number of calories

  • and lost the same amount of weight,

  • but most of the weight lost while getting 8.5 hours was fat,

  • whereas most of the weight lost when only getting 5.5 hours

  • of sleep a night was lean body mass.

  • Same diet, but with more sleep they ended up losing more than

  • twice as much body fat.

  • So you snooze you losefat!

"Does Lack of Sleep Cause You to Gain Weight?"

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