Many of us reach for comfort foods like ice cream and leftover takeout after a long day. But if you make late night snacking a regular habit, it could have unintended consequences on your health, experts say.
According to a recent study of the eating habits of more than 34,000 US adults, nearly 60 per cent said it was normal for them to eat after 9 pm.
Our bodies have evolved to process nutrients during the day – and to conserve and store energy at night, said Marie-Pierre St-Onge, a nutrition and sleep scientist at Columbia University. And disrupting that natural rhythm could cause problems, she said.
Several studies have found, for instance, that eating dinner within three hours of bedtime may worsen heartburn or acid reflux symptoms.
And limited research has suggested that eating one to three hours before bedtime is associated with more disrupted sleep.
The most intriguing research on late-night eating, however, has focused on its relationship with body weight and metabolic health, said Frank Scheer, a neuroscientist at Brigham and Women’s Hospital in Boston.
In one 2019 study of nearly 900 middle-aged and older US adults, for instance, Dr Scheer and his colleagues found that those who consumed roughly 100 calories or more within two hours of bedtime were about 80 per cent more likely to be overweight or to have obesity than those who did not eat during that window. Researchers have found similar results in adults in Sweden and Japan.
And in a 2023 study of more than 850 adults in Britain, those who regularly snacked after 9 pm had higher levels of HbA1c, a marker for diabetes risk, and greater spikes in blood sugars and fats after daytime meals than those who did not typically consume late-night snacks.
Such studies can’t prove that late-night eating directly causes weight gain or other health problems, because other factors, such as our genetics, exercise and sleep are also involved, he said. But recent research that controls for these factors has started to reveal direct effects of meal timing on health.