Outline of person's head with veggies, fruit and protein in the brain. Role of nutrition on mental health

The link between mental health and nutrition - Q&A with Louise Mercieca

We are all aware of how nutrition affects our physical health, but what we don’t always realise is how big of an impact it can have on our mental health.

In the past few years, the link between diet and mental wellness has gained considerable interest and there is increasing evidence that what we eat can significantly affect the way we think, how we behave and what we feel.

Following a balanced diet which is nutrient-rich, incorporating wholegrains into your meals, eating enough fruit and vegetables, having the right balance of fats and taking care of your gut health, amongst other things, can all help improve your mental health and emotional wellbeing.

We delved into this topic with Louise Mercieca, Nutritional Therapist and author of How Food Shapes Your Child, who has been working in the nutritional field since 2011 focusing mainly on children’s nutrition.


1. How are nutrition and mental health linked?

They are linked in many ways and this connection can be on quite a deep level. One of the most common ways is the way people view food. Many classify what they eat as 'good/bad' or 'naughty' and this perception of foods can lead people to feeling guilty or even ashamed by certain food choices. This type of food relationship can cause low self-esteem which then drives people towards diets or 'cures' which play on this low self-esteem but don’t encourage informed decisions based on nutritional education.

2. How and why does our nutritional status potentially affect our mood, behaviour, and thoughts?

The food we eat impacts every cell in our body, meaning that everything we eat influences every movement, every decision and every emotion.  Some foods help to maintain the natural balance within the body whereas others can create fluctuating and low moods.  The easiest example of this is sugar which creates a temporary high followed by a blood sugar and mood crash.  Natural foods can create ‘happy molecules’ which help the body to feel how it should: calm, content, happy, alert and sleepy.

3. Could you explain the connection between gut health and mental health?

This is a fascinating area of the body. Our gut and brain are connected via a bi-directional communication loop. Put simply they constantly talk to each other, and the conversation goes both ways.  We can help our mental health (as well as our physical health) by supporting the diversity of our gut microbiome.

Many aspects are governed or influenced by our gut, one of them being blood sugar regulation. Fluctuating blood sugar can lead to sugar cravings and physical symptoms such as fatigue, brain fuzz, irritability, wrinkles, upset tummy and poor sleep.

Another important factor is that our gut is involved in the production of serotonin.  Serotonin is a mood stabilising neurotransmitter. Neurotransmitters are the way in which the body sends messages and we need serotonin to feel calm and content to enable us to feel happy.

4. What should people eat for a healthy gut?

Our gut health is measured by its diversity and unfortunately, many foods are stripping the microbiome of this.  Ensuring that you eat plenty of ‘real foods’ and avoiding, as much as possible, overly processed and 'fake food' is the most important element.

Naturally colourful foods such as fruits and vegetables, particularly purple and blue foods, support gut health, as do prebiotics, which feed the existing ‘good bacteria’ in your gut, and probiotics, live cultures that populate the gut.

5. What is the role of ultra-processed foods (UPF) in declining mental health?

We have seen UPF’s cause a rapid deceleration of physical and mental health in the last twenty years as these options have increased in our food supply. These foods are nutrient devoid (lacking in fibre, good fats, protein, vitamins, minerals and antioxidants), which leads to many people being malnourished or at least, deficient in some nutrients.

Another aspect of these foods is the role they have on our brains. In the BBC programme "What are we feeding our kids?", Dr Chris van Tulleken switches to an ultra-processed food diet for 30 days. At the end of the diet, Dr Chris’ brain scan showed a huge increase in the number of new connections in the brain’s reward centre – this is the area that drives automatic and repetitive behaviours. The pleasure and reward centre of the brain is also linked with addictions and the results of Dr Chris’ brain scan showed ‘what we would expect to see in addicts’ and these changes did not return to normal once he came off the diet of UPF’s.

6. How can you implement a therapeutic approach to nutrition?

By understanding the role food has on our body.  We first need to appreciate our body and the biology of it and then we will be able to work with it.  Many people constantly work against their body.  Going from one ‘diet’ to another or limiting themselves because they feel that they should. If we consider the foods we eat and what they do for us and make informed decisions each time we eat then that’s a good start! Food is not to be used as a treat, a bribe, a comfort or a reward as these are all influencing factors in emotional eating.

7. How can people know what a good diet is?

Real foods. The most important factor for health is to eat foods that are as close to their natural form as possible.  If it didn’t walk, grow or swim then don’t eat it, at least don’t eat it often! Many foods today are engineered in a laboratory and are really quite different to the original food form.

8. What are the benefits of mindful eating?

One factor with UPF’s is that they encourage overeating.  They are designed to be highly palatable, the term used is ‘Hyper Palatability’ the ‘perfect’ mix of sugar, salt and fat to ‘tickle your taste buds’ and activate your senses. These foods are even designed to have the ‘perfect’ texture so you don’t have to work as hard chewing, meaning you can eat more quickly, use less energy to eat the food and eat more and more food without getting full. In short, ultra-processed foods bypass your body’s natural ability to feel full, these foods do not enable your body to produce Leptin, the hormone that tells you to stop eating.  This means you can eat without gaining any nutritional satisfaction or even any enjoyment.

Mindful eating enables you to chew and enjoy your food which then naturally encourages the hormone that tells you that you are full, ensuring that you gain nutritional satisfaction from your food.


Our physical and mental wellbeing are directly connected to what we put into our bodies. At Mr Lee’s we’ve always believed in the importance of nutrition when it comes to our overall health and that’s why our main mission is to create a range of instant foods with absolutely no nasties and non-hfss. 

Mr Lees Team