Does a bad night's sleep make you likely to overeat?

by Charlotte Hardman, The Conversation
Being tired is linked to eating unhealthy foods that may cause weight gain. Credit: Shuttershock

Few people would argue with the idea that sleep is good for us, but not many of us know that a lack of sleep can cause weight gain.

The health benefits of sleep are extremely well-documented. It provides protection from many medical and psychiatric conditions as well as having positive effects on mood, quality of life and well-being.

But more recently, mounting evidence has suggested that poor sleep is associated with an increased risk of obesity.

Short sleep duration appears to predict changes in weight over time. Children who were poor sleepers at three years of age, for instance, have been found more likely to be obese by the age of seven.

Sleep and brain function

While there are a number of possible explanations for the relationship between poor sleep and obesity, there's growing support for the idea that disrupted sleep increases food intake. This may be due to the effect of sleep deprivation on and the physiological control of appetite.

Some studies, for instance, indicate that short sleep duration increases levels of the gut hormone, ghrelin, which makes us feel hungry and often leads to increased eating.

Poor sleep might also increase the reward value of eating by making certain foods seem more attractive and increasing our motivation to obtain them. This idea is supported by recent research using functional magnetic resonance imaging (fMRI), which measures activity in specific regions of the by detecting changes in blood flow.

The study found that, in people with limited sleep, the brain regions associated with reward "lit up" more in response to pictures of tasty food, suggesting that sleepy people found these foods more appealing.

Sleep deprivation often leads to cravings for high-calorie food. Credit: Wikimedia Commons/Christian Razukas

At the same time, might also impair our ability to make decisions and exert self-control over .

In another recent brain imaging study, 23 healthy people had a night of normal sleep and a night of total sleep deprivation followed by fMRI scans.

After sleep deprivation, there was greater activity in the amygdala region of the brain (which is important for reward behaviour) in response to pictures of food. Sleep-deprived participants also reported a greater desire specifically for high-calorie foods compared to low-calorie foods.

At the same time, the scans showed other regions of the brain believed to be important for "higher-level" brain function and self-control were less active after sleep deprivation. This means sleepy people may be less able to control what and how much they eat.

So it seems sleep deprivation may promote over-eating via a two-pronged effect on brain function – the desirability of food is increased at the same time as higher-level processes that enable us to control how much we eat fail.

Understanding self-control

The idea that reduces our ability to inhibit certain behaviours also appears to make sense in the context of more general theories of self-control.

The Limited Resource theory, for instance, proposes that we have a finite reserve of self-control that can be used to regulate our behaviour, similar to a muscle that becomes fatigued under too much pressure.

When you are tired after poor sleep, you might have reduced self-control "strength", making you more likely to engage in disinhibited behaviours, such as over-eating unhealthy foods.

Indeed, a longitudinal study found over-tiredness in childhood predicted lower inhibitory control in adolescence which, in turn, predicted illicit drug use.

The next step for this line of research is to illustrate whether these findings apply to excessive consumption of food.

There is, in fact, growing evidence that poor inhibitory control is a critical factor in over-eating, along with other substance use disorders.

But it's important to consider alternative mechanisms that might account for the association between sleep, eating and obesity such as the dampening effect has on mood. After bad sleep, we may feel fed up or depressed, which might promote the eating of high-calorie "comfort foods".

Research in this area provides important insight into the causes of over-eating, obesity and potential intervention strategies. Helping people to improve the length and quality of may be one such approach.

Related Stories

Sleep to protect your brain

Dec 31, 2013

A new study from Uppsala University, Sweden, shows that one night of sleep deprivation increases morning blood concentrations of NSE and S-100B in healthy young men. These molecules are typically found in the brain. Thus, ...

Sleep deprivation increases food purchasing the next day

Sep 05, 2013

People who were deprived of one night's sleep purchased more calories and grams of food in a mock supermarket on the following day in a new study published in the journal Obesity, the official journal of The Obesity Societ ...

Study explains how sleep loss can make you fat

Aug 06, 2013

A sleepless night makes us more likely to reach for doughnuts or pizza than for whole grains and leafy green vegetables, suggests a new study from UC Berkeley that examines the brain regions that control ...

Recommended for you

Demographics impact family physicians' care of children

Sep 12, 2014

(HealthDay)—Demographic and geographic factors influence whether family physicians provide care for children, according to a study published in the September/October issue of the Annals of Family Medicine.

Estimate: 3 in 10 NFL retirees face cognitive woes (Update)

Sep 12, 2014

Nearly three in 10 former NFL players will develop at least moderate neurocognitive problems and qualify for payments under the proposed $765 million concussion settlement, according to data prepared for ex-players' lawyers ...

Physician describes impact of malpractice suit

Sep 12, 2014

(HealthDay)—A family doctor who was involved in a malpractice suit describes the impact on her practice of medicine in an article published online in the September/October issue of the Annals of Family Me ...

Report outlines 'must-have' sexual health services for men

Sep 12, 2014

(Medical Xpress)—Compared with women, American men have worse access to reproductive and sexual health care, research shows, a disparity fueled in part by the lack of standard clinical guidelines on the types and timing ...

New report finds a healthy well-being among Chinese children

Sep 12, 2014

A new study of children's well-being in Shanghai finds that first-graders are socially and emotionally healthy, with most performing average or above average academically. The study, by the New York University-East China ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

RobertKarlStonjek
not rated yet Jan 07, 2014
One of the confounders of these studies is the possible difference between the effects of a change of sleep regime. What effect does changing one's sleep pattern have?