Why You Might Be Reaching For That Second Cookie
The story of stress and comfort food
Are you a stress-eater; have you ever wondered why?
In this article, I will provide a possible answer to why this might be the case, based on research in the field of neuroendocrinology.
Neuroendocrinology: the study of the interaction between the nervous and endocrine systems.
Stress: The Catalyst Of It All
We all have stress in our busy lives. It can be a good thing in small and infrequent doses as it drives us to new limits. However, constant stress may have major psychological and physiological outcomes. For example, the Mayo Clinic writes that stress can be the catalyst of anxiety, anger, irritability, and depression. They further note that headaches, chest pain, and sleep problems may also arise.
We will investigate the impacts of stress on comfort food intake and how it might factor into stress-induced weight gain. Comfort food is defined as generally simple, palatable, as well as high in sugar and fats. Think of a cupcake or cookie, for example.
The Relationship Between Comfort Food Intake and Stress
In one riveting study conducted by Dr. Norman Pecoraro et al., predictions on the relationship between comfort food intake and stress were proposed.
The researchers focused on how the hypothalamic-pituitary-adrenal axis (HPA) — a complicated stress response system in the brain that communicates to our adrenal glands — communicates throughout the body, affecting food intake and stress levels. The predictions summarized are:
- Under chronic stress, the HPA produces an elevated amount of glucocorticoids — steroid hormones. These glucocorticoids increase one’s desire to consume comfort foods. A famous example of a glucocorticoid is cortisol.
- When one eats these comfort foods, they will have a metabolic response that acts alongside the glucocorticoids to “blunt stress responses” (Pecoraro et al, 2004). A.K.A, consuming these comfort foods will reduce stress.
How would one even support these predictions?
Through rat studies, unfortunately. Pecoraro et al.’s study consisted of rats split into four different test groups differing on diet and stress. The four groups were:
- non-stressed with regular chow diet
- non-stressed with comfort food + chow diet
- stressed with regular chow diet
- stressed with comfort food + chow diet
If you’re wondering, the comfort food for rats is apparently calorically dense lard and sucrose (yum!). Additionally, chronic stress in rats in this study was imposed through restraint. Essentially, the rats would be put into a plexiglass cylinder which they were unable to escape. While stressful, the rats were not in any pain. I will not comment upon the morality of it as that is a topic for a different article.
Results:
In this study, there are two major results:
- In both stressed and unstressed rats, groups with access to comfort food in addition to their regular diet gained more weight.
- In stressed rats, a larger proportion of calories was eaten from comfort food in comparison to their unstressed counterparts. In other words, in times of stress, the rats chose to eat a higher proportion of their calories in a day from comfort food rather than their regular chow.
These findings are important because they can help explain that a) comfort food is seen to be eaten at greater rates than regular food when stressed and b) comfort food consumption promotes weight gain.
At this point you might be telling yourself great, we have looked at the outcomes of stress’ and comfort food intake in rats. But what does that mean for humans? Well, let’s delve into it.
Stress and Comfort Food in Humans
For this section, I will be speaking about Dr. A Janet Tomiyama et al.’s work.
Remember the earlier mention of the HPA axis and glucocorticoids? Well, these researchers wished to investigate if stressed women’s consumption of comfort food (calorie-dense food) had any modulatory factors on the HPA axis (stress system) response. This axis response was measured by cortisol — the famous glucocorticoid mentioned before.
The study’s subjects consisted of fifty-nine premenopausal women ranging 20–50 years of age. As one cannot ethically chronically stress people, the researchers chose a population which would likely be chronically stressed in their daily life: parents of children with ailments. For control group purposes, some subjects who did not have children with ailments were chosen.
To ensure that the study was thorough and holistic, the researchers took three main types of measures: psychological, anthropometric, and cortisol.
Results
In this study, there were several major results. In women with high-stress levels, it was found that they had
- a higher BMI (Body Mass Index)
- higher levels of emotional eating
- lower levels of cortisol and cortisol response
These findings bring into conversation both of the research studies presented and are imperative to our understanding of comfort food intake and stress in the human population.
In one’s emotional eating, we can imagine that they are reaching for comfort foods as opposed to healthier options — leading to the increased BMI. This result is similar to the weight increase we saw in the previous study’s rat populations.
For the lower levels of cortisol and cortisol response in highly-stressed women, we refer to the earlier conversation of the HPA axis its modulation by comfort food consumption. When chronically stressed and consuming comfort food, one experiences the lowering amount of and response to stress hormones, as seen in the article by Tomiyama et al.
Do these hormonal responses of reduced stress mean that there is also psychological comfort when eating these foods? Just going off of this study, unfortunately, we cannot fully say. However, what we can is that there does seem to be a modulatory effect on the HPA axis by comfort food and its metabolism. These results support the original Pecoraro et al. work spoke about.
Conclusions
The discussion of the two studies presented has illustrated that there does seem to be a link between comfort food intake and stress. This might be by way of the suggested modulatory effects on the HPA axis or it might be from other unmentioned mechanisms. Either way, we have delved into a possible neuroendocrine explanation.
This work is largely important because it gives us a moment of pause in regards to our own stress levels and how they might affect us. Are we falling victim to excessive weight gain and therefore predisposing ourselves to numerous other diseases because we have undue stress? How might we reduce it so that we can live the healthiest lives possible? These are all personal questions that we must answer for ourselves, but research such as this definitely can serve as inspiration and information to best decide how we proceed.
Things to note:
Inspired by Gunnar De Winter’s writing, I propose several notes of caution that we should acknowledge in these two studies
- The HPA axis serves many purposes and so we might attribute a phenomenon to one when the other is actually at play.
- Rats and humans cannot truly be compared. While we have been conducting rat studies for 150 years and they are generally well understood and widespread, the mechanisms within the body of a rat and a human are different. Take the applicability of one to the other with a grain of salt. Two, perhaps.
- Like the HPA axis, cortisol has many purposes. Neuroendocrinology is a field that is ever-evolving due to the intricacies of hormones.
- The Tomiyama et al. study is not generalizable to the whole human population as it was conducted only on female mothers.
Did you enjoy this work? If so, please feel free to check out my others here! Also, feel free to write your thoughts down in the responses, I always love to hear from you all.