Sugary drinks linked to poor sleep
People who sleep no more than five hours a night consume significantly more sugary caffeinated drinks than those getting seven or eight hours of shut-eye, a study has shown.
But scientists say it is still not clear whether sugar-sweetened drinks make it harder to sleep - or if poor sleep causes people to seek out sugar and caffeine.
Both could be having an effect, they believe.
US lead researcher Dr Aric Prather, from the University of California at San Francisco, said: "We think there may be a positive feedback loop where sugary drinks and sleep loss reinforce one another, making it harder for people to eliminate their unhealthy sugar habit.
"This data suggests that improving people's sleep could potentially help them break out of the cycle and cut down on their sugar intake, which we know to be linked to metabolic disease."
Dr Prather's team analysed data from 18,779 participants in the National Health and Nutrition Survey, an ongoing US study of dietary habits and health.
Investigators recorded how much sleep people were getting as well as the consumption of various beverages. These included caffeinated and non-caffeinated sugar-sweetened drinks, fruit juice, artificially sweetened drinks, and plain coffee, tea and water.
The study found participants who regularly slept five or fewer hours per night also drank 21pc more caffeinated sugar-sweetened beverages than those who slept seven to eight hours per night. The beverages included both soft drinks and non-carbonated energy drinks.
People who slept six hours per night consumed 11pc more caffeinated sugary drinks, demonstrating a "dose effect" with more drinks associated with less sleep.