After using some data on obesity for an applied statistics course, it struck me that obesity is a good topic to research what really interests me: the intersection between psychological and physical health.

Obesity is an epidemic that has become a global issue. Research shows that diets often backfire and people end up gaining even more weight. To help people lose weight, a psychological approach could prove to be more effective. So my thesis topic became: the impact of emotions and different emotion regulation strategies on eating behaviour in women with a healthy weight and in women with obesity.

My own research project
I could have studied existing data, but I wanted to do my own project. I aspired to do a PhD after my master's and wanted to go through the whole process from data collection to the finished paper. I reached out to the professor whose data got me on the subject and she agreed to supervise my project.

One hundred women with a healthy weight and one hundred women with obesity filled out one initial questionnaire with questions on emotion regulation, eating disorder behaviours and weight. They also filled out a two-minute daily life questionnaire, seven days a week, five times a day. This experience sampling method gets you more ecologically valid data. Analyzing that data was the most challenging part of my research, but the results were interesting.

Negative emotions did not impact food intake
In the general questionnaire there was no difference in emotion regulation between the two groups, but in the daily life questionnaire obese women showed less adaptive emotional regulation strategies. Adaptive emotion regulation strategies lead to behaviour that is in line with long term goals (e.g. maintaining a healthy weight). In both groups negative emotions did not have an impact on food intake, but positive emotions did! Positive emotions caused more unhealthy food choices and more taste-driven eating. It is possible that, since some people eat more and some people eat less due to negative emotions, those behaviours cancelled each other out in my study.

Surprising result
We did not expect adaptive emotion regulation strategies to lead to overeating in both groups. A potential reason for that could be the way in which we characterized emotion regulation in our study. We had participants score a list of emotion regulation scores (e.g. suppression, rumination, distraction) and categorized these as adaptive or maladaptive. However, research shows that there may be no such thing as adaptive or maladaptive in strategies, but that it depends on context. Another explanation for this finding could be that people with obesity are less sensitive to feeling gastric distension, and are not so good at determining when they have overeaten. 

Positive emotion regulation
According to this study, people are more likely to eat more when they feel better. They eat to boost or at least keep that positive feeling. Helping them to manage other ways of feeling better could help them decrease food intake. Indeed, emotion regulation can also be applied to positive emotions and this may be useful in weight loss treatments.

More research is needed on emotion regulation strategies. There are therapies that target emotion regulation that are, particularly for binge eating disorder, effective. But according to my study, we don’t know if targeting emotion regulation is needed for people with obesity in general. We didn’t find an effect of emotion regulation on food intake. Also, there is not much research on positive emotions leading to increased eating, so it is important that this is explored more.

First chapter
What I learned from my research master is that it takes a lot to plan and run a study and get the outcomes and that I really enjoy research and academic writing. In my PhD, which I started a few weeks ago, we will follow up on the results. In particular we will take into account (dietary) restraint status, which was not in this study. It would be interesting to have more experience sampling data, next to the lab studies and the longitudinal study we have planned. My master’s thesis might very well be the first chapter of my PhD thesis.