Stress and Weight Gain

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You hear time and time again that stress contributes to weight gain. It may be easy to assume that when we are stressed, we sometimes eat more and exercise less, but there’s way more to the story than this.

This week, we will take a deep dive into a paper from UCLA published in 2019 that really gets into the nitty gritty details of how stress can lead to weight gain and also how weight gain can lead to stress. I think you’ll come to agree that obesity and stress are much more intricately related than previously thought.

 First of all, though, let’s take a quick look at what exactly stress is.  In this paper, the author defines stress as “a negative emotional experience accompanied by predictable biochemical, physiological, cognitive and behavioral changes that are directed either toward altering the stressful event or accommodating to its effects.”

The stress response actually dates back all the way to our caveman days. In those days, our stressors were primarily life-threatening situations. So when we were being chased by a sabertoothed tiger, our body would release glucose into the bloodstream so that we would be ready for fight or flight. This response is necessary when a tiger is trying to make you its next meal.

The problem is that your body will interpret any type of stress the same way. In today’s society, our stressors are much more likely to be psychological, such as hard times at work, fighting with a spouse, or worrying about money, for example. Our body will still release glucose into the bloodstream in the same way it would if you were being chased by that sabertoothed tiger.  However, since we don’t need that glucose to fight or flight in these situations, it ends up being stored as fat.

Many of the pathways that lead from stress to weight gain are really the result of our attempts to deal with the negative emotional aspects of stress. The author breaks these pathways into four different domains, including cognition, behavior, physiology and biochemistry. Let’s take a look at each one in turn.


We all know from personal experience that stress can mess with your mind, specifically executive function and self-regulation. This means that when stress levels are high, our ability to think, plan and organize are diminished, as is the ability to focus and manage our emotions. The author describes a study in which children were asked to choose between a moderate plate of candy now, or take a larger plate of candy later. Children with more cumulative life stressors were more likely to choose the large plate of candy, and these children also ended up having higher BMIs three years later.


Again, we can all describe times when stress influenced our eating, physical activity and sleep behaviors.  In fact, the author states that 39% of American adults engage in stress eating, with multiple studies showing that as stress goes up, so does our consumption of sugar and saturated fat. Studies also consistently show that higher stress levels correlate with decreased physical activity. Likewise for sleep; unfortunately, shorter sleep duration is also independently correlated with obesity. This is partly due to the fact then we’re tired, we tend to crave high-fat and high-sugar foods, we don’t engage in as much physical activity, plus we’re awake longer, giving us more time to eat.


The author highlights three different ways stress affects us physiologically. First, it hikes up our stress hormones, particularly cortisol. Cortisol causes obesity by both stimulating us to eat more, and by encouraging the storage of fat, particularly around our mid-section. Second, it hikes up the brain’s appetite for the feel-good hormone dopamine. Dopamine drives you to eat foods that are high in sugar and fat, and the more you eat, the more dopamine is released, driving you to overeat those high-calorie foods. And finally, stress has been shown to alter the microbiome, and although the research in this area is fairly new, it’s becoming clear that the microbiome directly influences body weight.


Leptin and ghrelin are hormones that affect our hunger and appetite. Leptin suppresses appetite and ghrelin stimulates it. Although the relationship is complicated, it is clear that stress contributes to the levels of both of these hormones.

 So far, we’ve discussed how stress contributes to obesity. Unfortunately, obesity also causes stress, which puts us in a negative feedback loop, in which stress leads to weight gain, which leads to more stress, which leads to more weight gain, and so on. 

In our society, weight stigma is prevalent, and has been shown to affect employment, healthcare, and educational settings. Experiencing weight stigma is interpreted by the body as stress, just like being chased by that sabretooth tiger in our caveman days. In fact, this has been measured in studies that purposely expose people to weight stigma.

 So how does all of this affect our approach to nutrition and weight loss? Well, the short answer is that our approach has to be about far more than just the food. We have to address all the aspects of our life that create stress, or contribute to our stress, and also look at how we manage stress day-to-day. This is why coaching is such an effective tool for weight loss. We are able to look at not just what you eat, but who you are while you’re eating.

The bottom line here is that focusing on diet without addressing the underlying stress in our lives is a broken strategy.

Developing improved stress management skills and emotional regulation skills will not only make it easier to lose weight from a physiological perspective, it will also make eating and lifestyle changes much easier.

One of the best ways to address stress in our lives is to develop a mindfulness practice. Next week we’ll take a look at study that looks at how music can encourage mindful eating.


Tomiyama AJ. Stress and Obesity. Annu Rev Psychol. 2019 Jan 4;70:703–18.