How Your Thoughts Influence Your Digestion and Metabolism

Why you shouldn't feel guilty this Thanksgiving

Your brain is intricately connected to your gut. The enteric nervous system (ENS) is often referred to as your "little brain" and contains more than 100 million nerve cells [1]. The vagus nerve is the longest cranial nerve in your body and connects your brainstem and intestines. Your vagus nerve allows your thoughts to influence your gut and vice versa. The butterflies you feel in your stomach, are due to this connection [2]. The connection between your ENS and your brain allow for your perception of food can influence your digestion. Let's examine how your thoughts can influence your digestion.

Placebo Effect

Most people have heard of the placebo effect -- how one can experience physical/mental benefits due to the belief that they are receiving treatment. A study tested a new chemotherapy treatment. One group received the real chemotherapy, while the other received a salt water injection. Shockingly, 31% of the patients receiving the placebo treatment (salt water injection) lost their hair. This demonstrates the power of one's mind. By simply believing that they were receiving chemotherapy, 31% of patients actually lost their hair [3]!

Just imagine how the beliefs you hold about yourself and the food you eat can have real effects in your body. For example, if you expect a food to hurt your stomach (such as dairy, sweets, etc), the belief itself might make your stomach hurt [2]. This isn't to say that food intolerances don't exist and that there aren't certain foods that will hurt your stomach more than others. It is, however, worth examining your beliefs around food.

How Our Thoughts Influence Our Digestion

As demonstrated by the placebo effect, our thoughts can influence physical processes in our body. Even though our thoughts cannot change the nutrients in food, they can influence how our bodies metabolize these nutrients [3].

When you are about to eat something, it is first visually processed in your cerebral cortex. This information is then communicated to your limbic system, including your hypothalamus which is located here. The limbic system regulates your emotions, hunger, thirst, temperature, heart rate, and more. The hypothalamus influences the release of hormones and is responsible for activating either your parasympathetic (rest and digest) or sympathetic nervous system (fight or flight) [4]. It is important to remember that your brain doesn't differentiate between a true stressor (lion chasing you) and a perceived stressor (worrying that a food will make you feel gross) [5].

When your sympathetic nervous system is activated, blood is pulled away from the digestive tract (making it more difficult for food to be digested) [2]. Because your body isn't able to digest the food as easily, you are also more likely to experience GI discomfort such as bloating or constipation [4]. Insulin and cortisol are both spiked, affecting how your food is metabolized and causing more food to be stored as fat [4, 6].

All of these symptoms can be caused by worrying over the food you are eating. Recognize the power of your mind. If you are worrying and stressing over what you eat, does it really matter if you are eating a "perfect meal" or allowing yourself to indulge in a delicious dessert with family and friends?

"You can eat the healthiest meal on the planet, but if you’re thinking toxic thoughts, stressed out, and in a state of sympathetic nervous system dominance, the digestion of your food goes down and your fat storage metabolism can go up... Likewise, you can eat a nutritionally challenged meal, but if your head and heart are in the right place, the nutritive power of your food will be increased [5]"

Example

If you are eating and are present and enjoying the moment, your hypothalamus will receive this information as positive. This will activate the parasympathetic nervous system, stimulating your digestive system from your salivary glands to your gallbladder. Your metabolism will also be activated. This allows your body to absorb the maximum amount of nutrients from the food you're eating [4, 5].

If you are eating something and are thinking negative thoughts or feeling guilty, these negative emotions will be viewed as a stressor. Your hypothalamus will activate your sympathetic nervous system. Your digestion, gastrointestinal motility, mucosal secretion and blood flow to your digestive organs will all be inhibited. This results in the slowing of digestion and negatively influences your gut microbiome while also increasing the amount of toxic by-products in the bloodstream [4, 5].

The Milkshake Study

One study examined how thinking about food affects how it is metabolized. Participants received one of two milkshakes. The two milkshakes were identical, they were only described differently. One was described as a low-calorie, no sugar, no fat shake. The other was described as a high-calorie, high fat and high sugar shake.

The researchers then measured ghrelin levels in participants. Ghrelin is known as the "hunger hormone" because it lets your body know when it's hungry. As ghrelin levels rise, metabolism slows. The participants who drank the "high-calorie" shake had a 3 times higher drop in ghrelin levels than the group who drank the "low-calorie" shake. In other words, the participants who believed they were drinking a milkshake with more calories felt less hungry after consumption [7].

This is a great, real-life example of how what your mind believes about your food can influence your digestion, hormones, and hunger. If you are restricting what foods you eat and not allowing yourself to fully enjoy what you truly want, your mind may trick your body by telling it it's still hungry. If on the other hand, you allow yourself to indulge in what you truly want, you are more likely to feel truly satiated.

Enjoy Your Food

Focus on being in the present moment with your friends and family

Repeat a mantra: If you experience anxiety or guilt around a certain food, pick out a mantra to repeat to yourself. For example "I deserve to eat this" or "this food fuels my body and soul."

Focus on the experience: Allow yourself to fully enjoy the food by noticing the taste, smell and texture to fully savor the food.

Eat in a calm environment: Try not to engage in stressful conversations while eating.

Eat slowly

Take deep breaths before eating: This will help activate your parasympathetic nervous system

Focus on enjoying the food and the experience

References

Johns hopkins medicine. The brain-gut connection. https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-brain-gut-connection

Nohling, R. (2018, January 9). How your mindset can affect your physical response to food. The real life rd. https://www.thereallife-rd.com/2018/01/mindset-digestive-health/

Fielding, J. W., Fagg, S. L., Jones, B. G., Ellis, D., Hockey, M. S., Minawa, A., Brookes, V. S., Craven, J. L., Mason, M. C., Timothy, A., Waterhouse, J. A., & Wrigley, P. F. (1983). An interim report of a prospective, randomized, controlled study of adjuvant chemotherapy in operable gastric cancer: British Stomach Cancer Group. World journal of surgery, 7(3), 390–399. https://doi.org/10.1007/BF01658089

Lomas, E. (2023, January 30). Here’s how your gut is affected by your thoughts. Medium. https://medium.com/curious/heres-how-your-gut-is-affected-by-your-thoughts-1efecc8ce1d7

David, M. (2015, February 20). The psychology of food: mind food. Psychology of eating. https://psychologyofeating.com/mind-over-food/

Suzuki, K., Simpson, K. A., Minnion, J. S., Shillito, J. C., & Bloom, S. R. (2010). The role of gut hormones and the hypothalamus in appetite regulation. Endocrine journal, 57(5), 359–372. https://doi.org/10.1507/endocrj.k10e-077

Crum, A. J., Corbin, W. R., Brownell, K. D., & Salovey, P. (2011). Mind over milkshakes: mindsets, not just nutrients, determine ghrelin response. Health psychology : official journal of the Division of Health Psychology, American Psychological Association, 30(4), 424–431. https://doi.org/10.1037/a0023467