Nutritional Psychology: How Food and Diet Can Influence Your Mental Health

Most discussions on food revolve around its role in nutrition and physical health, with an unhealthy diet as a leading risk factor for chronic diseases. However, a 2021 study published in Nutrients sought to explore the associations between dietary choices, sleep quality, and mental health symptoms. By drawing on a dataset from the UK Biobank, researchers found that high intakes of fruit, vegetables, fish, and fibre were positively associated with healthy sleep and fewer mental health symptoms. Meanwhile, processed meat consumption had an inverse association with sleep and mental health.

Interestingly the impacts of diet might not be immediately obvious to us. This week I read about this study which compared the sleep of a small groups of men who were assigned either a high-processed diet for two weeks or a healthy diet (including balanced nutrients and low-processed foods). Participants reported experiencing no difference to the length or quality of their sleep yet their EEGs showed a different story, with less restorative "slow-wave sleep" happening on the high-processed diet. Whilst this may not be noticeable in the short-term, the long term effect of having less restorative sleep will make you more susceptible to illness and less resilient to life's stresses. As these findings suggest that diets can support the management of sleep and mental health symptoms, it's worth taking a closer look at nutritional psychology, which studies the relationship between food intake and various aspects of psychological well-being. A better understanding of nutritional psychology may then inform effective ways to boost your mental health through food and diet. This is something I regularly talk to my therapy clients about too because it's an upward battle trying to support someone with their mood if they aren't getting the right nutrients to support this.

The link between food and mental health While nutritional psychology is still a burgeoning field, there’s a wealth of research documenting the close relationship between the gut and the brain. For example, nutritionally dense foods promote the growth of ‘good’ bacteria in the gut microbiome, positively affecting the production of chemical substances in the gastrointestinal tract. One of these chemicals is serotonin, a neurotransmitter that doesn’t just help you digest food but also guides your sleep, mood, and emotions. Another biological pathway that may explain the link between food and mental health is inflammation. Since the brain states that affect the pathophysiology of mental disorders also tend to activate inflammation, diets that contain anti-inflammatory foods like whole foods and omega-3 fatty acids can help lower the risk of developing depression. In fact, 2022 research from The American Journal of Clinical Nutrition has shown that the anti-inflammatory effect of the Mediterranean diet can improve depressive symptoms and overall quality of life.

Tips for boosting mental health through food and diet

Plan your meals Now that you know how nutrient-rich foods can help improve your mood, emotions, and other mental health aspects, it makes sense to incorporate them into your diet. A few years ago after maternity leave I followed the WeightWatchers’ weight loss programme, and learnt first-hand how well their approach to customising meals met both my nutritional needs for good wellbeing as well as helping me to reach my physical health goals.

For better mental and emotional health, we need to include whole, unprocessed foods and nutrients like antioxidants, fibre, omega-3 fatty acids, and vitamins. But it’s hard to drop the habit of eating processed foods, especially if you are an emotional eater or dealing with a lot of stress in your life.

That's where a programme like this helped me as it doesn’t rely on rigid rules, instead guiding my eating habits toward healthier choices and portion sizes (in line with up-to-date nutritional and behavioural science). As such I found it much easier to adhere to healthier eating both during and after I did the programme as it helped me develop better habits. If you need a hand with getting your diet more nutritionally balanced and developing better food habits too then a programme like this makes total sense. It breaks everything down into easy choices and will include many nutrients needed for your mental wellbeing.

Make healthy swaps

A helpful way to ease the transition into a diet largely composed of nutritious and mood-boosting foods is to swap your favourites with their healthier counterparts. Last year nutritional therapist Ione wrote this blog post for us about eating well for your mental health where she gave some great examples of this, for example you can try replacing pasta with vegetable spirals, flour with buckwheat and milled flaxseed, and cereals with smoothies. Being able to eat your comfort foods while still sticking to the principles of nutritional psychology encourages you to continue the dietary changes you’ve made.

With my own clients we often talk about just making a tiny swap to start with e.g. a morning snack, eating a piece of fruit first. Making decisions about these swaps when you are feeling calm will help too as they aren't easy to make when you are feeling stressed or emotional (often when you will then reach for the high-energy snacks).

Pay attention to hunger cues

Although this focuses more on dietary patterns rather than exact food choices, it still helps to pay attention to hunger cues as you adopt nutritional psychology into your diet. Since hunger can be a driving force for negative emotions and low moods, remember to respond to your body’s natural cues and eat when you feel hungry. Otherwise, you may experience higher tension, anger, depression, fatigue, and confusion. If you find yourself dealing with unnecessary cravings throughout the day, foods rich in fibre and protein can help boost fullness while also benefitting your mental health. Nutritional psychology can be a powerful tool in understanding how lifestyle choices like diet can influence our mental health. Remember that the mental health benefits of nutritious foods may not be immediate and instead take weeks or months for you to notice, but the impact of eating and living healthier will be felt for years.

What next?

Read these blog posts: Why do I eat junk food when I’m stressed? or How to eat well for your mental health.

Book recommendation for going deeper on gut health and mood: Gut by Guilia Enders

Book recommendation for learning how to stick to routines and adopt health habits: Tiny Habits by B.J. Fogg.

If you engage in emotional eating get in touch to discuss therapy which can help with this.