When I was in high school, I had a keen interest in nutrition: What food was considered healthy? Was there a schedule of eating I should follow? Three big meals a day or just snacks throughout? How many calories should I consume? Do I eat too much sugar or too much fat? I considered studying Nutritional Sciences in college to dive deeper into these questions and maybe become a specialist in the field. However, a part of me was unsatisfied with the state of the field. There seemed to be inconsistencies and great variability for what is the “correct” nutrition.
Fast forward ten years to where I am now: a fifth-year Neuroscience PhD student. It wasn’t until I was on the path to becoming a neuroscientist—someone who studies and researches the nervous system and brain—that I discovered the possibility of connecting eating behavior to neuroscience. I’ve now returned to my interest in eating, but from a new perspective. As I became more familiar with the science of how the brain regulates the feeling of hunger and satiety, it quickly became obvious that eating is more complicated than just acquiring food and digesting it. Recent research has clearly shown a complex and fascinating reciprocal interaction between the brain and the gut. What we eat affects the brain, and the brain in turn affects everything from nutritional status to gut activity to eating behaviors.
Critical discoveries over the last few decades about basic eating behaviors have demonstrated how our brains respond to hunger cues and how they know when to tell our body we are full and no longer need to keep eating. For instance, hormones such as leptin and ghrelin are produced in the stomach but also directly interact with the brain to, respectively, decrease and increase appetite.
Nevertheless, there are many facets of eating – hunger, satiety, taste, energy balance, pleasure – and, moreover, the brain is a complex and intricate system. So, we keep asking more questions about how various pathways in the brain can have direct effects on certain aspects of eating behavior. My research aims to understand how emotion and eating are connected. Emotion and eating are undoubtedly connected behaviorally if we think about how common it is to reach for a pint of ice cream when we’re sad, how feeling stressed can lead to overeating, or how grief can suppress appetite. The association between emotion and eating is also seen in the fact that eating-related disorders, such as anorexia nervosa and obesity, are very often present with psychiatric conditions like depression and anxiety. By studying specific regions and cells in the brain that are responsible for regulating both emotional and eating behaviors, we hope to identify targets for treatment of eating disorders, or to at least gain a deeper understanding of how to ensure both optimal nutrition and pleasure in eating.
The neuroscience of eating is particularly interesting because it gives us an understanding about our eating behaviors: how they evolved and the way they exist in this modern world with its excess of convenient and extremely tasty food. Why is it so hard not reach for another French fry after you’ve already eaten the rest of your meal? How is it that a “second stomach” seems to grow when it’s time for dessert? Mechanisms and signaling processes in the brain affect how you respond to food. Our brains are wired to make us want to eat as much as possible! This is because our brains developed to survive when food was not always a certainty, but often a rather limited resource, one that required physical work to obtain. Eating is certainly a more complex process than it may seem at first glance!
Eating and food-related issues are not uncommon. Conditions like anorexia, obesity, diabetes or colitis are all costly and can even be deadly. Some of these affect young people or begin early in life but could be mitigated in the future by understanding better how the brain and gut talk to each other, and how emotions and environment can influence the onset of such conditions.
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Post by guest writer: Wesley Ilana Schnapp
PhD Candidate, Neuroscience GIDP
Cai Lab, Dept of Neuroscience
University of Arizona