Fast food, including a burger and fries, on a tray in a restaurant.

Eating well: Advice and science from an expert

Kimberley Wilson, chartered psychologist and author of ‘Unprocessed’, shares her insights on ultra-processed foods and the small changes to our diet that can make a big difference.

19 February 2024

By BPS Communications

There’s a very large and loud conversation about ultra-processed foods going on at the moment. But it's also true to say that the kinks are still really being worked out in terms of a) what we mean when we say a food is ultra-processed and b) what we understand about the impact of that food. I.e. the underlying mechanism of how it might impact physical and mental health. 

Brain nutrients 

From my perspective, I start from the position that your brain is the hungriest organ in your body. It has a huge energy demand and alongside that a huge nutrient demand. So, for example, essential fatty acids, EPA and DHA in particular, form a large proportion of the membrane of your brain cells, helping them to send signals. That’s basically everything that your brain does! 

But then your neurotransmitters, serotonin, acetylcholine, dopamine are made from nutrients, so your brain's literal structure and function depend on nutrients that have to come in sufficient quantities from your diet.  

Ultra-processed foods 

And this is where there is a concern around the standard diet in the UK and the US too, where ultra-processed foods make up to 60 per cent of the average adult’s diet, potentially creating a nutritional crisis for the brain, because what we know is that the higher the proportion of your diet is from ultra-processed foods, the lower your nutritional status. 

It’s a particular concern for the 20 per cent of children in the UK who get nearly 80 per cent of their energy from this category of foods. The higher the proportion of UPF they get in their diet, the less likely they are to get the nutrients their rapidly developing brain needs to function well.  

No drastic solutions 

If we're looking to improve or remedy that situation, we don’t do that by completely overhauling the diet - we know that's a very ineffective strategy. It's not very efficient and it's very, very difficult.  

It's not about starting an extreme plan, throwing everything out of your cupboards and starting all over again. That's not how psychology and the psychology of eating works. For me, it's about introducing more nutrient dense foods into your current dietary intake. Perhaps adding fruit to your breakfast cereal, or a side salad to the sandwich or ‘meal deal’ that you're eating at lunchtime. Changes like that will help to increase the nutrient density of your foods, to start providing your brain with the nutrients that it needs. 

Top tips to improve your diet   

In particular, you could focus on polyphenol rich foods - brightly coloured foods like berries and deeply coloured fruit and vegetables. Also, fibre is particularly important for protecting the brain. When your gut microbes break down fibre, they produce short chain fatty acids that protect the integrity blood brain barrier.  

On a population level in the UK, omega three fatty acids are very low, particularly EPA and DHA which are the main omega threes for brain health, so increasing our intake is really important. Eating two portions of oily fish per week or getting a DHA rich supplement to make up any shortfall in your dietary intake can really help. 

That’s where I would start. Nothing extreme, nothing excessive, but just starting to feed your brain the nutrients it needs to function well and happily at the start of 2024. 

Kimberley Wilson

About the author

Kimberley Wilson is a chartered counselling psychologist with a master's degree in nutrition,.

She is the author of the books How to Build a Healthy Brain and Unprocessed: What Your Diet Is Doing to Your Brain.

She has written for BBC Science Focus and Psychologies Magazine, hosted the podcast Made of Stronger Stuff and the scientific segment of One Dish both on BBC Radio 4, appeared regularly on Lorraine ITV and been the featured mental health expert on several Channel 4 series and documentaries.

Read more on these topics