Considering obesity drugs? Here's how sleeping more could help you lose weight

Lack of slumber increases our appetite, especially for salty, fatty foods

Sleep deprivation doesn’t just increase the amount of food eaten - it can also lead to cravings for snack foods high in fat, salt, and sugar

The world seems to be in thrall to the new wave of anti-obesity drugs, which suppress appetite and cravings.

In 2023, the journal Science named the development of GLP-1 agonists to treat obesity — and their efficacy at blunting health problems — the ‘breakthrough of the year’.

Since then, the appetite for GLP-1 agonists for people with obesity has exploded: 15m people in the US now take these medications and brands such as Ozempic and Wegovy have become household names.

A critical factor in the success of the agonists is their appetite-diminishing effect, particularly the craving for foods full of saturated fat, sugar, salt, and additives. The food industry is rapidly responding to these changes in consumption habits.

But another factor, though less newsworthy, is sleep deprivation and its ability to dramatically influence both our appetite and our hunger for junk food.

Before we reach for weight-loss drugs, we need to fix our sleep. Sleeping fewer than seven hours a night increases weight.

Multiple forces combine to expand your waistline. The first concerns two hormones that control appetite: leptin and ghrelin.

Leptin signals a sense of feeling full. When circulating leptin levels are high, your appetite is blunted and you don’t feel like eating.

Hunger is triggered by ghrelin. When ghrelin increases, so does your desire to eat.

An imbalance of these hormones can trigger increased eating and body weight. If both hormones are out of sync, the effect on weight is magnified further.

In a series of studies at the University of Chicago over the last three decades, researchers examined the link between sleep and appetite. In a paper published in the journal Sleep Medicine (2008), the researchers allowed one group of healthy individuals to sleep for eight and a half hours a night and the second group only four to five hours a night for five nights.

Before we reach for weight-loss drugs, we need to fix our sleep

Short sleepers were ravenous compared to those who slept for more than eight hours, despite being given the same amount of food and being similarly active.

The strong rise of hunger pangs and increased reported appetite occurred by the second day of short sleeping.

At fault were the two hobbit-sounding characters: leptin and ghrelin.

Inadequate sleep decreased concentrations of the satiety-signalling hormone leptin and increased levels of the hunger-instigating hormone ghrelin.

It is a classic case of double jeopardy. Too little sleep and the ‘I’m full’ signal is dialled down and the ‘I’m still hungry’ signal is amplified.

Further experiments, by Dr Eve Van Cauter at the University of Chicago, found that when short-sleeping, the same individuals ate 300 calories more each day — or well over 1,000 calories before the end of the experiment — compared to when they were getting a full night’s sleep.

Dr Van Cauter found that similar changes occur if people get five to six hours of sleep a night over 10 days.

Scale that up to a working year and you will have consumed up to 70,000 extra calories. Based on caloric estimates, that could amount to 10 to 15 pounds of weight gain a year.

But sleep deprivation doesn’t just increase the amount of food eaten - it can also lead to cravings for snack foods high in fat, salt, and sugar (HFSS).

In another series of experiments, published in the journal Sleep (2016), researchers examined the impact of sleep deprivation on cravings for snack food.

They found that sleep-deprived individuals, despite eating almost 2,000 calories during a buffet lunch, ate an additional 330 calories by snacking after the full meal — biscuits, chocolate bars, crisps — compared to what the same individuals ate when they had enjoyed a full night’s sleep.

More recent evidence confirms that sleep loss increases levels of circulating endocannabinoids, chemicals similar to cannabis that stimulate appetite and increase your desire to snack on HFSS foods.

Combine an increase in endocannabinoids with alterations in the hormones leptin and ghrelin caused by sleep deprivation and you have a potent brew all driving you in one direction — overeating and snacking. These behaviours can lead to weight gain, obesity, and chronic disease.

Getting enough sleep can help you control body weight. Van Cauter and her researchers showed that a full night’s sleep reduces the desire for snack foods by repairing the communication pathways in the brain that control cravings.

Ample sleep of seven to nine hours can restore impulse control within the brain and put the appropriate brakes on excessive eating.

More recent research shows that plentiful sleep makes the gut happier, improving the bacterial community known as the microbiome.

We now know that short sleep increases hunger and appetite, compromises impulse control within the brain, increases food consumption (especially high-calorie foods), and decreases feelings of food satisfaction after eating. So before taking weight-loss drugs, make sure you are getting plenty of sleep.