Stress Eating Junk Food Leads to More Weight Gain than Junk Food Alone

It is not a big secret that a proper diet is a smart strategy for optimal health, but what we continue to learn is that it is not just what we eat—and how much—but also when we eat that can contribute to certain health outcomes. 

For example, a new study advises that eating while stressed—or because of stress—could result in gaining more weight than if you ate the same amount of calories without the stress.  Apparently, this effect is linked with a certain molecular pathway in the brain controlled by none other than insulin.  Of course, this highlights an already big advisement against eating food as a way to deal with stress (and other negative emotions). 

Conducted at the Gavin Institute of Medical Research, the study examined mice in a laboratory setting.  Some of the mice were placed under conditions of chronic stress and this test population suffered faster onset of obesity than the mice who were protected from stress, even though both groups were fed the same high-fat food. The researchers identified a molecule they call NPY that is naturally produced in the brain as a response to stress; and this molecule stimulates eating in mice as well as in humans.

Lead study author Dr. Kenny Chi Kin Ip explains, “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.”

But let’s backtrack to the controlling mechanism of metabolism:  insulin. The body produces insulin after consuming a meal to absorb blood glucose and to tell the brain when you are “full”. Stress can cause a person to overeat and this results in chronically elevated insulin levels; and this causes nerve cells in the amygdala to develop insulin insensitivity.

Once the amygdala becomes desensitized to insulin, NPY levels rise. This leads to an increase in both eating and, subsequently, weight gain.  Over time this becomes a vicious cycle that can become as difficult to break as an addition, especially if you are not able to get out of these stressful situations or environments. 

Research team leader, and Head of the Garvan Institute Eating Disorders laboratory, Professor Herbert Herzog concludes, “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.”