Sometimes the only thing that gets us through a stressful day is a belly full of comfort food.
But it could be time to step away from the Krispy Kremes because it turns out stress eating, particularly of calorific foods, leads to more weight gain than eating when you’re not stressed.
A new study, published in the journal Cell Metabolism, found that when we’re stressed, comfort eating can lead to us putting on more weight.
A team, led by Professor Herbert Herzog, Head of the Eating Disorders laboratory at the Garvan Institute of Medical Research, analysed the behaviour and weight gain of a group of mice.
They found that when mice were stressed over an extended period of time and high-calorie food is available, they became obese more quickly than when they consumed the same food in a stress-free environment.
Researchers believe that this was, in part, because the stressed mice ate a lot more than their chilled-out counterparts.
But trying to look further into the reasons behind the differences in weight gain between the stressed and the non-stressed mice the scientists hypothesised that it was something to do with a molecule called neuropeptide Y (NPY), which the brain produces in response to stress to stimulate eating.
“We discovered that when we switched off the production of NPY in the amygdala weight gain was reduced,” explained lead author Dr Kenny Chi Kin Ip.
“Without NPY, the weight gain on a high-fat diet with stress was the same as weight gain in the stress-free environment. This shows a clear link between stress, obesity and NPY.”
According to nutritionist Fleur Borelli our bodies normally produces insulin just after a meal to help cells absorb glucose and to send a “stop eating” signal to the brain to indicate that we’re full.
Stress alone raises those insulin levels a little, but when we’re stressed and we turn to calorific comfort food, those insulin levels really spike.
Over a long period of time, our nerve cells become desensitised to insulin, eventually this stops them from detecting it all together.
“If we are producing too much insulin and too frequently eg by eating too often and by eating high calorie meals then the body stop responding to insulin and sugar does not get into the cells,” Borelli explains. “This is known as insulin resistance and is the pathway to metabolic disorders such as type II diabetes.”
This then leads nerve cells to boost their NYP levels, which encourages us to eat more and stops us from being able to burn energy through heat.
“The brain misreads this situation as if there is no energy coming into the body and increases a molecule called neuropeptide Y which increases our appetite and our ability to store fat,” she explains.
“This is why stressed mice fed on the same diet as non-stressed ones can put on weight more easily. It is a survival strategy based on the fact the brain thinks there is no food around because the body has stopped responding to high insulin levels,” she adds.
In other words, it becomes a vicious cycle.
“Our findings revealed a vicious cycle, where chronic, high insulin levels are driven by stress and a high-calorie diet promoted more and more eating,” explained Professor Herzog.
“This really reinforced the idea that while it’s bad to eat junk food, eating high-calorie foods under stress is a double whammy that drives obesity.
“This study indicates that we have to be much more conscious about what we’re eating when we’re stressed, to avoid a faster development of obesity,” Professor Herzog added.
That’s something Julie Lamble, senior nutritionist at Lifeplan, manufacturer of vitamins, minerals and botanical supplements agrees with.
“Stress stimulates the adrenal glands to trigger glucose to be released, through the hormone cortisol causing insulin levels to rise which causes hyperglycaemia, or high blood sugar levels,” she explains.
“Normally, low blood sugar levels stimulate the body to release stored body fat to use it for energy and therefore having high levels of blood sugars makes our body store fat and over time will lead to obesity.”