Can Losing Sleep Make You Gain Weight?

Research indicates that sleep is one of the many factors in how our bodies create, store, and burn fat. We explore (and offer a few tips for getting the most out of your sleep) in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:02):
Welcome to brain Stuff from How Stuff Works Hi brain
Stuff Lorn vogelbaumb here. An increasing number of studies are
finding a direct connection between sleep deprivation and weight gain. Generally,
people who get at least seven hours of sleep per
night have less body fat than people who don't. There are,
of course, other factors involved in determining who will become

(00:23):
overweight and who will not like food and take exercise
and genetics, but sleep is a more integral part of
the process than most people realize. In a study involving
nine thousand subjects between nine two and four, researchers found
that people who averaged six hours of sleep per night
were twenty seven percent more likely to be overweight than
their seven to nine our counterparts, and those averaging five

(00:46):
hours of sleep per night were seventy three percent more
likely to be overweight. Many people who are sleep deprived
don't even know it. Lots of us think that there's
quite a bit of give and how much sleep a
person needs to be healthy and well functioning, but most
researchers disagree, putting seven hours as the minimum for everyone
except the very young and the very old. Besides straight numbers,

(01:08):
there are a couple ways to tell if you're sleep deprived,
including how fast you fall asleep at night. Most non
sleep deprived people take about fifteen minutes to fall asleep.
Falling asleep almost instantly, along with chronic sleepiness, is a
good indicator that you're not getting enough sleep. If you
are sleep deprived, there are some obvious tie ins to obesity,
like your sleepiness making physical activity less likely, but there

(01:31):
are also a number of things going on in your
body that could contribute to weight gain. In scientific studies,
the most commonly sided effects of sleep deprivation are hormonal disturbances,
specifically involving the hormones lepton and grellin. When you don't
get enough sleep, your body has too little leptin and
too much grellin. Let's unpack that the hormone leptin is

(01:52):
intricately involved in the regulation of appetite, metabolism and calorie burning.
It's the chemical that tells your brain when you're full,
when it should start burning up calories, and by extension,
when it should create energy for your body to use.
It triggers a series of messages and responses that starts
in the hypothalamus and ends in the thyroid. Gland. The
thyroid gland controls the way your body stores and uses energy.

(02:15):
During sleep, leptin levels increase, telling your brain you have
plenty of energy for the time being and that there's
no need to trigger the feeling of hunger or the
burning of calories. When you don't get enough sleep, you
end up with two little leptin in your body, which,
through a series of steps, makes your brain think you
don't have enough energy for your needs. So your brain
tells you you're hungry even though you don't actually need

(02:36):
food at that time, and it takes steps to store
the calories you eat as fat so you'll have enough
energy the next time you need it. The decrease in
leptin brought on by sleep deprivation can result in a
constant feeling of hunger and a general slow down of
your metabolism. The other hormone found to be related to
sleep and wait is grellan. The purpose of grellin is

(02:58):
basically the exact opposite of lept in. It tells your
brain when you need to eat, when it should stop
burning calories, and when it should store energy as fat.
During sleep, levels of grellan decrease because sleep requires far
less energy than being awake. People who don't sleep enough
end up with too much grellan in their system, so
the body thinks it's hungry and it needs more calories,

(03:19):
and it stops burning those calories because it thinks there's
a shortage. Some scientists hypothesize that these hormonal changes that
occur during sleep are the result of an evolutionary process
that favored humans who could survive the food shortages of winters.
Traditionally speaking, winters have long nights and little food, and
summers have short nights and an abundance of food. With

(03:40):
shorter nights comes less sleep, less leptin, and more grellin,
making the body eat as much as possible and save
those calories for the long winter ahead. With winter comes
more sleep, meaning more leptin and less grellin, both of
which tell the body it's time to burn those calories
it's stored during the summer. Sleep deprivation has also been
ound to increased levels of stress hormones and resistance to insulin,

(04:04):
both of which can contribute to weight gain. Insulin resistance
can also lead to type two diabetes. The National Sleep
Foundation offers the following tips to help make sure you
get enough sleep for your body to function optimally, try
to aim for seven to nine hours of sleep per night.
Increase your exercise level, but try not to exercise within
three hours of your bedtime, and don't ingest caffeine or

(04:26):
alcohol near your bedtime. Caffeine can keep you awake, and
alcohol can disrupt the normal stages of your sleep. Today's
episode was written by Julia Layton and produced by Tyler
Clang and Tristan McNeil. For more on this and lots
of other hefty topics, visit our home planet, how Stuff

(04:47):
works dot com.