Can sleep affect your weight?

Body coach star, Joe Wicks, suggests that diets are rubbish and that sleep is key to weight maintenance. But is he right, can lack of sleep affect the way our bodies deal with weight loss?

The Research

This idea isn’t new. In 2011, the Express reported that “good sleep is dream recipe to lose weight”.

In this article, it was reported that people who sleep more than 8 hours per night and lead a stress-free lifestyle were more likely to lose weight than stressed dieters who got little sleep.

This article is based on a study conducted by researchers from the Kaiser Permanente Centre for Health Research in the US where 472 obese adults underwent a six month intensive weight loss programme which involved:

• a calorie deficit diet of 500kcal per day
• eating a low-fat diet
• exercising every day
• recording everything they eat, drink and their exercise
• setting out a plan to meet short term goals
• attend group meetings run by counsellors and nutritionists

The researchers also recorded sleep time, stress levels and states of depression as perceived by the participant.

So this was a self-reported, subjective score that was taken at the beginning of the trial.

The results showed that those who had less stress levels, slept between 6-8 hours per night, were more likely to lose targeted weight than those who slept less than 6 hours, more than 8 hours or who reported the highest stress levels [1].

A later study suggested that insomnia can affect our ability to maintain weight loss too [2].

Some studies even suggest that using the weekend to catch up on lost sleep might have a beneficial effect on our weight [3] , although this is purely observational.

So what can we make of this?

These are interesting studies, and suggest that good quality sleep does help keep the weight off.

But none of them imply that sleep alone will make you thin. You still have to follow a calorie-deficit weight loss plan and exercise.

If you want to keep that weight off, and let’s face it, who doesn’t? Then you also need to factor in a good night’s sleep – regularly; whether or not your can make up for lost sleep over the weekend is yet to be proven.

So why does sleep and stress affect our weight?

It’s quite a complicated interplay between our hormones, our metabolism and what is called a circadian rhythm, which is one of the many body clocks we have.

The wake –sleep cycle affects an appetite hormone called ghrelin, or “the hunger hormone” because it switches on the body’s sensors that make us feel hungry.

It’s possible that disrupted sleep can confuse the circadian rhythm within our stomachs. There are cells that secrete the hormone ghrelin in order to trigger the feeling of hunger, so this hormone is always raised before a meal, and drops straight after.

But there is an element of timing within this cycle, which stops us from eating at night time when our body wants to sleep. This is disrupted in people with night eating syndrome and therefore could be one cause of obesity [4].

Our sleep-wake cycle can often determine our preference for foods; shaping our desire for sweet foods, fatty foods or savoury foods at particular times of the day [5].

Some studies show that shift-workers are more prone to obesity because their disrupted sleep pattern influences their desire for high calorie foods in the morning [6].

Ghrelin can also play a role in promoting food cravings and drive our behaviours behind the types of food we desire following periods of stress [7].

Some studies suggest that stress and weight are related, particularly with inactive people who do not engage in exercise [8].

Stress, in all of its forms, causes a rise in the hormone cortisol, also known as the “stress hormone“.

Like adrenaline (the “flight or fight hormone”), cortisol rises in response to a stressful or panic-driven situation, contributing to a higher heart-beat, flushing and sweating which is eased when adrenaline subsides.

But cortisol doesn’t, it remains high for sometime and if stress is continuous, you get a chronic state of raised cortisol.

Cortisol is higher in the morning and lower in the evening, suggesting that low cortisol helps us sleep and high cortisol helps us wake [9].

So it’s directly affected by our sleep-wake patterns. When we’re stressed or sleep-deprived, cortisol increases and could, over time, impact on our natural cortisol rhythm.

Moreover, this disruption in this hormone cycle can have profound effects on our health, including links to disease states [10].

In studies, it has been found that the higher our weight, the higher our cortisol which could be due to the amount of  additional stress our body is under with heavier weight [11].

This causes disruptions in circadian rhythms, disruptions in our sleep patterns and therefore doesn’t help this cycle of weight-gain and poor eating choices.

How do we manage this?

Now that we know how poor sleep can disrupt our bodies’ natural rhythms and cycles, and how these can impact upon our eating behaviour, how do we escape this?

The obvious key is stress-management. But first, we have to acknowledge the fact that we are under stress.

In some people, chronic stress can somehow feel normal, because they’re always feeling that sense of urgency, or need to keep on top of things.

It doesn’t seem like stress to all of us, but being in a heightened state of alert all the time takes its toll on your body.

So it’s time to relax. It’s time to strike the right work-life balance. But how? These are just a few of the best stress-busters, and one just might suit you:

• Physical activity has to be up there, because although physical activity does stress the body, it relaxes the mind. Doing some form of physical activity also helps sleep too.
• Wind-down time: just 30 minutes reading a book, doing a gentle hobby or even spending time with the dog helps you wind-down and reconnect your body and mind again.
• Leave the wine or beer glass in the cupboard. Whilst you might think an alcoholic drink will relax you, alcohol disrupts sleep and even if you feel you’ve slept all night, you won’t get the true deep-relaxing and restorative sleep your body demands, because alcohol interferes with that.
• Try something Eastern. It might sound a bit whacky, a bit leftfield, but any or all of meditation,  mindfulness, yoga have been shown in studies to really help slow the pace of your mind, improve sleep and reduce stress [12, 13, 14, 15].

So yes, whilst it’s not the entire picture, good sleep every night can impact your waistline.

Resources

For a comprehensive resource on all things sleep hygiene, sleep medicine and health – visit www.tuck.com