If you thought that the one time you were safe from putting on weight – safe from reaching into the biscuit tin for another digestive, or sneaking a piece of cheese from the fridge – was when you were tucked up in bed asleep at night, think again. Especially if you're someone who likes to slumber with the light on.
New research, undertaken by Breakthrough Breast Cancer (owing to the link between obesity and cancer) has found there is a link between sleeping in well-lit rooms and rising levels of obesity. If anything's going to finally get you down to Ikea to buy some proper blinds to replace that sheer gauzy material you call a curtain, it's this.
113,000 women were asked to rate the amount of light in their bedrooms at night, ranging from 'light enough to read' to 'too dark to see your hand or you wear a mask', with their answers being compared to measures of obesity including BMI, waist-to-hip ratio and waist circumference. And guess what? All were higher in women who slept in lighter rooms.
So what's going on here? Is light making us fat? Well, one explanation could be that light disrupts the body clock and sleeping patterns (it makes it harder to drift off properly), altering our mood and even the way we process food during a 24-hour cycle.
Prof Anthony Swerdlow, from the Institute of Cancer Research, told the BBC: 'In this very large group of people there is an association between reported light exposure at night and overweight and obesity.'
'But there is not sufficient evidence to know if making your room darker would make any difference to your weight.'
'There might be other explanations for the association, but the findings are intriguing enough to warrant further scientific investigation.'
So next time you get in from the pub, ready to pass out on the bed shoes still on, chips and pitta in hand, at least turn off the light.
Picture: Ada Hamza
This article originally appeared on The Debrief.