While most people are aware through personal experience that one unhealthy food choice is likely to lead to another, we now have research to back this up. In a study by Dr. Stevenson and his colleagues, it was found that the addition of junk food to our daily diet impairs our ability to control our appetites.1 One structure of the brain, the hippocampus (best known for its role in learning and memory) is influenced exponentially by what we eat. While previous studies from Dr. Stevenson have shown that a western-style diet is associated with a smaller hippocampus2, his most current study takes a look at what this means for controlling our dietary desires and portion control. Dr. Stevenson’s study illuminated that when junk food is eaten in addition to a participant’s regular diet, they are more likely to continue eating junk food even when they are not hungry. In addition to this, the participants also performed worse on tests of learning and memory when eating foods high in saturated fat and sugar.
What exactly does learning and memory have to do with regulating our appetites? To answer this question, it is important to consider the role of reward pathways within the brain. This is because reinforcement of a reward involves both learning and memory. Add to this information the high-sensory experience of a western-style diet, and making conscious food choices that benefit our mental health and mood becomes a difficult task.
The foods we eat impact our physiology, and when they do so quickly – like junk food does – both our brains and body remember. For example, we remember how a piece of chocolate cake makes us feel because it causes our insulin to spike, giving us a sugar rush and releasing feel good chemicals. Add this memory to the multitude of context that is a part of the human experience (i.e. a stressful experience, or perhaps just visually seeing a piece of cake) and it is likely we will elicit a craving. This high-sensory experience of anticipation, pleasure and reward is encoded in our memory, making us more susceptible to choosing high-fat and sugary foods in the future.
To add dimension to how and why we experience cravings, we should also consider dopamine’s role in the reward pathways. Dopamine, the neurotransmitter involved in feeling pleasure, is released in anticipation of a reward.3 This is particularly important because it enhances reward-related memories, strengthening synapses in the Hippocampus.
What our brain doesn’t take into account however, is the long term implications of these “rewards.” Through the reinforcement of these high-sensory foods, we impact the metabolic processes responsible for our mental health, mood, and subsequently – outlook on life.
What does this mean for everyday life? How can you learn to take conscious control of your own Diet-Mental Health relationship? Increasing your Interoceptive Awareness can help. Interoception, which is the sense that provides information about the internal condition of our body—how our body is feeling on the inside5, is a key element of Nutritional Psychology. Not surprisingly, Interoception is also influenced by a western-style diet. Eating junk food not only affects our brain structures and functions, but it also influences our brain-body connection. In one study, those who consumed a western-style diet had a more difficult time connecting to their internal cues.6
This has implications not only for recognizing physical signals of fullness and satiety, but also for identifying and managing emotionally complex sensations that may arise from your body. When you consider the bidirectional nature of your internal sensations and emotions — for example, your heart beating faster when you’re anxious, or your stomach feeling queasy when you’re nervous — it is understandable that your emotions and dietary intake are related. While it may be a good idea to go for a walk, or call a friend, it’s not uncommon for most people to self-regulate in emotional eating. And what do people reach for when they’re eating due to emotions and not physical hunger? Usually they reach for highly palatable foods.
Thus the viscous cycle continues of experiencing high-sensory, highly-palatable junk food that causes strong connections through dopamine release, while at the same time making us less interoceptively aware. In this way, we are left with a lack of appetitive control from both a brain and body perspective.
The diet-mental health relationship is complex. When it comes to taking control of your dietary patterns, and making conscious decisions that will support your mood and mental health, research shows that increasing your Interoceptive Awareness (IA) is a great place to start.7
When it comes down to it, the bad news is that your brain is plastic. However, the good news is… well, your brain is plastic.8 This means that our brain is capable of change because our brains are constantly being shaped by experience. Neuroplasticity means that connections within the brain are constantly becoming stronger or weaker, depending on what you use.
This is unfortunate when we consider the vast landscape of highly-palatable foods surrounding us. However, when we understand some of the complex mechanisms taking place when we eat a western-style diet, and how this impacts our ability to regulate our appetite, we can shift our focus from that of will-power and self-blaming to a more intrinsic and sustainable approach.
This intrinsic approach involves increasing our IA through mindfulness — that is, moment-to-moment awareness, developed by paying attention to the present moment as non-judgmentally as possible. While this may seem far-fetched and almost mystical to some, research shows that developing a mindful approach does change the brain.9 More specifically, mindfulness has been shown to strengthen the insula, which scientists think is the brain structure responsible for Interoception.10
Our brain is constantly changing with every experience we have. Learning to increase your Interoceptive Awareness and make dietary choices that support your mood and mental health helps you to not only to keep an emotional balance, but also a physical homeostasis.
| 1. | Stevenson RJ, Francis HM, Attuquayefio T, et al. Hippocampal-dependent appetitive control is impaired by experimental exposure to a Western-style diet. R Soc Open Sci. 2020;7(2):191338. |
| 2. | Jacka FN, Cherbuin N, Anstey KJ, Sachdev P, Butterworth P. Western diet is associated with a smaller hippocampus: a longitudinal investigation. BMC Med. 2015;13(1):215. |
| 3. | Dopamine: “the anticipation molecule.” Thecolemaninstitute.com. Published January 27, 2016. https://thecolemaninstitute.com/tci-blog/72-dopamine-the-anticipation-molecule/ |
| 4. | Halber D. Motivation: Why you do the things you do. Brainfacts.org. https://www.brainfacts.org/thinking-sensing-and-behaving/learning-and-memory/2018/motivation-why-you-do-the-things-you-do-082818 |
| 5. | What is interoception? Kelly-mahler.com. Published September 25, 2018. https://www.kelly-mahler.com/what-is-interoception/ |
| 6. | Sample CH, Jones S, Hargrave SL, Jarrard LE, Davidson TL. Western diet and the weakening of the interoceptive stimulus control of appetitive behavior. Behav Brain Res. 2016;312:219-230. |
| 7. | Herbert BM, Blechert J, Hautzinger M, Matthias E, Herbert C. Intuitive eating is associated with interoceptive sensitivity. Effects on body mass index. Appetite. 2013;70:22-30. |
| 8. | Your brain is plastic! Neuwritesd.org. Published September 17, 2020. https://neuwritesd.org/2020/09/17/your-brain-is-plastic/ |
| 9. | Powell A. Harvard researchers study how mindfulness may change the brain in depressed patients. Harvard Gazette. Published April 9, 2018. https://news.harvard.edu/gazette/story/2018/04/harvard-researchers-study-how-mindfulness-may-change-the-brain-in-depressed-patients/ |
| 10. | Sharp PB, Sutton BP, Paul EJ, et al. Mindfulness training induces structural connectome changes in insula networks. Sci Rep. 2018;8(1):1-10. |
Missy December 23, 2020
Very interesting this Interoception awareness.