Researchers at The University of Nottingham have conducted a new study and suggested that daylight could help control weight.
Previous studies have revealed that the activity of calorie-burning 'brown fat', also known as brown adipose tissue (BAT), is reduced with obesity. Therefore, promoting BAT function could prevent or reduce obesity in some people.
Now, the new study has shown - for the first time - that daylight is a major factor in controlling BAT activity.
"Our research has suggested a previously unknown mechanism for controlling BAT function in humans and this could potentially lead to new treatments for the prevention or reversal of obesity," said study's lead author Michael Symonds, Professor of Developmental Physiology in the School of Clincal Sciences at the university.
Winter was traditionally a time of the year that was accompanied with increased thermal demands and thus energy expenditure, but the body's requirements for BAT has been reduced in recent times by central heating plus global warming.
BAT is capable of producing up to 300 times more heat per unit mass compared with all other tissues.
The researchers studied well over 3500 patients. The presence of BAT was documented and correlated with monthly changes in daylight and ambient temperature.
Their results showed that BAT was more common in females and that changes in BAT activity were more closely associated with day light than ambient temperature.
BAT is activated by the cold and is unique in being able to produce very large amounts of heat - but little is known about the main factors that regulate the amount of BAT in our bodies.
"Our research demonstrates a very strong seasonal variation in the presence of BAT. The study focused on the impact of daylight and ambient temperature, as these are two key factors in determining BAT function in small mammals. Our exciting new findings may help us find novel interventions aimed at promoting BAT activity particularly in the winter," Symonds said.
The study has been published in the journal Diabetes.