There are lots of explanations why people tend to gain weight during the winter. And now, University College London experts have discovered another - central heating.
Writing in the journal Obesity Reviews, the experts explain there's a potential link between weight gain and high indoor temperatures during winter. In other words, the majority of people live and work in buildings that are centrally heated these days - and the lack of exposure to the cold is making us fat.
There's a good reason why the reduced exposure to cold may have an effect on our ability to maintain a healthy weight, the researchers claim. Spending much of our time in heated indoor environments during this time of year means our bodies don't have to use up much energy to keep us warm.
But that's not the only reason. The lack of exposure to the cold could be affecting our bodies' production of brown fat. Researchers believe brown fat development in the body is triggered by exposure to cold temperatures. And the reason you want more brown fat than white fat is that brown fat has the capacity to burn energy to create heat. The more brown fat you have, the more calories you burn. At least that's the theory.
According to the study's lead author, Dr Fiona Johnson, all this increased time spent in centrally heated buildings during the winter means we're burning less energy. "This could have an impact on energy balance and ultimately have an impact on body weight and obesity," she adds.
Is your thermostat turned up to the max?