The Effects of Stress and Cortisol on Weight Gain

We’ve all watched a movie with a bucket-of-ice-cream post-break-up scene, right? But it’s not purely fictional, emotional eating is actually a thing and there’s science to back it up. Stress, whether due to post-relationship issues, financial problems, or other general anxiety problems, can have detrimental effects on the body, and may cause weight gain. Let’s take a closer look.  

What is Stress?

Stress is an instinctive experience designed to help us react to situations that need a response. It keeps us alert, motivated, and ready to avoid danger. While acute stress (stress for a short period) is a process that has protective effects, chronic stress leads to damaging effects to the body and a greater risk of depression, heart disease, diabetes, autoimmune disease, and weight gain [R, R].   

So how does stress have such a significant effect on the body? When we’re in a stressful situation (whether real or perceived), the brain signals the body to release high levels of a hormone called cortisol. Cortisol then has a wide range of effects on the body [R].

The Effects of Cortisol

Cortisol is a steroid and is able to affect a vast number of cells including liver cells, muscle cells, fat cells, and pancreatic cells. Its principal overall effect is the increase of blood sugar levels so there’s more available for the brain to use in a stressful situation. For example, in the liver, high levels of cortisol increase the production of glucose (or sugar). In the muscle, cortisol signals muscle cells to take up less glucose from the blood and instead, use protein as an energy source. In fat tissue, it increases the breakdown of fat cells to make more glucose, and in the pancreas, it decreases the hormone insulin (which is a hormone that makes cells take up glucose) [R].

While increased cortisol levels for a short period of time is beneficial to allow alertness and motivation, chronic high cortisol can have unfavorable consequences.   

How Are Stress and Weight Gain Linked?

Chronic psychological stress (such as financial problems, depression, or general anxiety problems) is associated with weight changes but there are several factors that seem to affect this. Weight gain is observed in individuals who already have a higher body mass index (BMI) prior to a stressful period [R]. This is because stress influences eating behaviors as well as food choices [R]. While acute stress suppresses appetite, chronic stress usually promotes cravings of high-fat and energy-dense foods.

Emotional eaters are people who tend to eat more when under stress, but this observation is affected by many factors including gender, genetics, and even personality. For example, women are more likely to consume more calories than men when exposed to stress [R].

In addition, chronically high cortisol levels (which implies a long-lasting stressful period) are associated with abdominal obesity [R]. The reason for this is not yet fully understood, and it seems that cortisol isn’t the only chemical involved in stress-induced weight gain. Researchers propose that there’s a large interplay between different hormones in the body that become dysregulated under stress and cause weight gain, with many other factors simultaneously involved, including the duration of stress and the types of food available for the stressed person to consume.