Scientists from King’s College London have discovered that people who sleep for longer are less likely to pick sugary treats, or reach for comforting carbohydrates.
Lack of sleep was already known to be a risk factor for obesity because it alters levels of hormones which control appetite.
But a new study showed that by getting more sleep, people naturally choose healthier foods within a week, eating on average 10 grams less sugar each day.
Principal investigator, Dr Wendy Hall, of the Department of Nutritional Sciences said: “The fact that extending sleep led to a reduction in intake of free sugars, by which we mean the sugars that are added to foods by manufacturers or in cooking at home as well as sugars in honey, syrups and fruit juice, suggests that a simple change in lifestyle may really help people to consume healthier diets.”
In the trial, 21 volunteers who slept for less than the recommended seven hours a night, were sent to counselling to learn how to change their habits so that they could sleep for longer.
They were asked to keep a constant bedtime, resist caffeine and food before bed and try and relax in the evenings. On average the groups were able to add 90 minutes to their daily sleep patterns over the seven day study period.
Food diaries kept throughout the trial showed that by the end of the week, they were naturally eating less sugar and carbs than at the start. In contrast, no change was see in a control group whose sleep did not improve.
Lead researcher, Haya Al Khatib, also from Kings College added: “Sleep duration and quality is an area of increasing public health concern and has been linked as a risk factor for various conditions. We have shown that sleep habits can be changed with relative ease in healthy adults using a personalised approach.
“Our results also suggest that increasing time in bed for an hour or so longer may lead to healthier food choices. This further strengthens the link between short sleep and poorer quality diets that has already been observed by previous studies.
“We hope to investigate this finding further with longer-term studies examining nutrient intake and continued adherence to sleep extension behaviours in more detail, especially in populations at risk of obesity or cardio-vascular disease.”
The research was published in the American Journal of Clinical Nutrition.