Nanogirl Michelle Dickinson: How to sleep your way slim and healthy

A lack of sleep alters the levels of the hormones ghrelin and leptin, which help to control our appetite.Picture / 123RF

If you want to lose weight, staying in bed and sleeping more may seem counterintuitive, however, new research shows it could be the secret to staying slim and living longer.

Scientists from King's College London studied 42 volunteers who admitted to sleeping less than seven hours a night. Current guidelines recommend seven to eight hours of sleep as an ideal amount for health and longevity meaning that these volunteers were consistently getting less sleep than is considered healthy.

In the study, half of the volunteers were given sleep advice and asked to keep the same bedtime each night, stay away from caffeine and electronics before bed, be conscious about their eating habits so that they weren't too full or too hungry before bed and use techniques to relax during the evening.

They were also given personal sleep counselling sessions to help them to understand the importance of sleep as well as techniques to help improve their own sleep time and quality.

The other half of volunteers were not given any advice and only asked to track their sleep and food habits while keeping their daily schedules the same as they had before. All of the volunteers were asked to wear sleep trackers and to keep detailed food diaries for the duration of the study.

At the end of four weeks, the volunteers who were given the advice were able to add an average of 90 minutes more sleep each night than they had previously been getting. The group that received no advice showed no change in how much they slept over the study period.

In addition to sleeping more, food diaries from the strict bedtime volunteers also showed that they had eaten on average 10g less per day of free sugars. Free sugars are sugars that have been added to foods and drinks by manufacturers and tend to be in processed foods such as biscuits, chocolate and fizzy drinks.

New Zealand recommendations suggest that adults and children over 11 should be consuming no more than 30g of total sugar per day which includes sugars that naturally occur in fruit and milk, so reducing the amount of free sugars eaten by a third is a significant change to the daily diet.

The better sleeping group also decreased the amount of carbohydrates that they ate giving them a reduced overall calorie intake just by spending more time in bed.

Sleep deprivation is also known to be a risk factor for obesity, increasing the amount of a stress-response hormone called cortisol that is produced. Increased cortisol levels can prompt the body to store more fat as well as encourage the body to use muscle as energy resulting in less muscle and more fat for those who sleep too little.

A lack of sleep can play havoc on the body by altering the levels of the hormones ghrelin and leptin which help to control our appetite.

Being conscious of eating habits before bed also reduces the risk of late-night snacks, which tend to be higher-calorie snack foods, and going to bed earlier reduces the time available for snacking.

This study published in the American Journal of Clinical Nutrition agrees with previous research which followed 1500 volunteers over six years and found that those who became obese during the study slept only 6.3 hours on average per night compared with the volunteers who kept a healthier body weight who slept more.

So the good news is that if you are trying to lose weight and reduce your calorie intake, getting more sleep could be a cheap and effective strategy for a longer, lighter and healthier life.