We’ve all been stressed out after a long day at work, so rather than cooking a nice meal we dive headlong in to a bag of chilli Doritos, Ben and Jerry’s ice cream or three glasses of wine and a breadstick.
Comfort eating has never really needed a reason, sometimes it feels good to gorge yourself on food that is probably unhealthy but scientists in Texas have tried to find out why it feels so good, and after some research found that our body actually creates a “hunger hormone”.
Experiments with mice have suggested that the body makes extra amounts of an important appetite hormone to combat the effectiveness of stress-induced depression and anxiety.
The findings could also have implications for understanding eating disorders such as anorexia nervosa and bulimia nervosa.
The study showed that when both mice and people do not eat, levels of a hormone called ghrelin rise in the gut, sending increased hunger signals to the brain.
The study, which was led by Jeffery Zigman of the University of Texas Southwestern Medical Centre in Dallas, found that the body produced extra quantities of ghrelin in response to stress. This hormone is part of the body’s natural defence against stress, as it tends to reduce typical depressive and anxious behaviour. It does, however boost the appetite, which leads to comfort eating.
“Our findings in mice suggest that chronic stress causes ghrelin levels to go up and that behaviours associated with depression and anxiety decrease when ghrelin levels rise,” Dr Zigman said. “An unfortunate side-effect is increased food intake and body weight.”
Michael Lutter, another member of the research team, said: “Our findings support the idea that these hunger hormones don’t do just one thing. Rather, they co-ordinate an entire behavioural response to stress and probably affect mood, stress and energy levels.”
The research was published in the journal Nature Neuroscience and raises the prospect that blocking the body’s response to ghrelin might help people who struggle with their weight, but could also be problematic as it is likely to affect your mood and stress response.
Dr Zigman said: “This new research suggests that, if you block ghrelin signalling, you might actually increase anxiety and depression, which would be bad.”
Dr Lutter said that, despite this drawback, the research may still shed important light on the biological processes behind some eating disorders.
“We’re very interested to see whether ghrelin treatment could help people with anorexia nervosa: the idea being that, in a certain population, calorie restriction and weight loss could have an antidepressant effect and could be reinforcing for this illness,” he said.
