Binge eating at night? It might be hormonal
Most dieters know the hard truth: Sticking to a weight-loss regimen gets more difficult as the day wears on. But while those who give in to food cravings and binge at night may blame flagging willpower, a new study suggests the problem could lie in the complex orchestra of hormones that drive hunger and signal feelings of satiety, or fullness.
The small study of 32 obese men and women, half of whom had a habit of binge eating, suggests that satiety hormones may be lower during the evening hours, while hunger hormones rise toward nightfall and may be stoked even higher by stressful situations. Overweight binge eaters may be particularly susceptible to the influence of fluctuations in these appetite-regulating hormones, the researchers found.
“There’s more opportunity to eat in the evening, but this study is showing that hormonal responses are setting them up to do this,” said Susan Carnell, an assistant professor of psychiatry and behavioral sciences at Johns Hopkins University School of Medicine who was a first author of the study along with Charlotte Grillot of Florida State University. It’s not clear whether these hormonal patterns precede and cause the binge eating behaviors or are conditioned by an individual’s eating habits, Carnell said. But either way, “you can get stuck in the cycle.”
The study is an important reminder that myriad factors contribute to weight gain, and that shaming and blaming people for their weight problems is inappropriate, said Kelly Costello Allison, director of the Center for Weight and Eating Disorders at the University of Pennsylvania, who was not involved in the new research.
“There is so much bias and judgment about people who are overweight, that it’s their fault or they’re lazy or just don’t have enough willpower,” Allison said. “The bottom line is that people are wired in different ways, and some of that does really depend on these biological markers.”
The new findings were published in the International Journal of Obesity in December. They build on earlier work, including a 2013 Harvard study of normal-weight individuals that found circadian rhythms play a role in regulating appetite, and that hunger peaks in the evening and appetite is, paradoxically, at its lowest in the morning, even though people have not eaten all night.
That research helped explain why so many people skip breakfast, even as evidence mounts that consuming most of one’s calories at the beginning of the day is optimal for weight control and a healthy metabolism.
Evening hunger “may have been an evolutionary adaptation that helped us get through the night,” said Dr. Satchidananda Panda, a professor at the Salk Institute for Biological Studies in San Diego. “For millions of years, our nighttime period was a time when we didn’t have access to food, and you also could not just get yourself food as soon as you woke up in the morning.”