When it comes to weight control, people tell themselves to avoid indulging in high-calorie foods.
But avoiding eating when you are stressed is even more important because stress activates a pathway in the brain causing more weight gain.
Some people lose their appetite under stress but most people eat more and crave more high calorie foods containing fat and sugar.
A study suggests that eating high-calorie foods under stressful conditions results in putting on more weight than eating the same foods without stress.
They reveal that while the hypothalamus in the brain regulates food intake, the amygdala responds to emotion and anxiety.
When we are stressed a neuropeptide Y (NPY) molecule in the amygdala is produced causing more weight gain.
Dr Kenny Chi Kin Ip, the study’s first author, said:
“Our study showed that when stressed over an extended period and high calorie food was available, mice became obese more quickly than those that consumed the same high fat food in a stress-free environment.
We discovered that when we switched off the production of NPY in the amygdala weight gain was reduced.
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.”
After having a meal our body produces insulin so cells can take the glucose from the blood and it signals the hypothalamus to stop eating.
But stress combined with high calorie foods increases insulin levels more than 10 times than when we eat the same food with no stress.
The more insulin in the amygdala, the less sensitive the nerve cells will become.
These nerve cells are responsible for producing NPY and this situation they will increase their NPY production.
The consequences are that the body asks for more food and also stores the fat and sugar instead of using them for fuel.
Professor Herbert Herzog, the study’s leader, said:
“Our findings revealed a vicious cycle, where chronic, high insulin levels driven by stress and a high-calorie diet promoted more and more eating.
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.”
About the author
Mina Dean is a Nutritionist and Food Scientist. She holds a BSc in Human Nutrition and an MSc in Food Science.
The study was published in Cell Metabolism (Ip et al., 2019).