Dr Kerr begins each day with a glass of warm water and lemon juice, followed by the fermented milk drink kefir.

The University of Adelaide systems and neural complexity expert also eats plenty of other fermented foods and plant foods rich in polyphenols, which act as antioxidants, but no “junk” food or excess sugar (black chocolate is her weakness).

It’s a diet followed not purely in the interests of physical health, but also because it helps ensure healthy brain function.

“One of the things I look at [in my work] is how to keep your brain healthy, how to grow new brain [neurogenesis] and how to think more nimbly,” she says.

“With neurogenesis, I look at the five ways you build brain and one of them is diet, so it’s really quite critical as it feeds our microbiome.”

At the Open State festival in October, Dr Kerr will speak with chef Simon Bryant at a Future Food session titled Is Your Diet Making You Dumb? The idea for the session, to be chaired by wine writer and marketer Paul Henry, came about through a discussion of the way in which many neurotransmitters, neurotrophins and chemicals such as serotonin created in the gut have both an immediate and long-term effect on how the brain works.

But Is Your Diet Making You Dumb? will go further, exploring the idea that “breaking bread together” – sharing a meal with family members, workmates or in social situations – may also benefit the mind.

The scientific findings regarding the myriad ways in which diet and brain function are linked can be mind-boggling.

Healthy foods feed the gut microbiota which improve our levels of brain plasticity (its ability to adapt and rewire itself) and neurogenesis (the birth of new brain cells), as well as increasing the size of the hippocampus (the area of the brain mainly responsible for learning and memory).

A diet of “junk” or processed foods (with a high level of trans fatty acids, emulisers, salt and sugar) has the opposite effect. It also sets off chain reactions in the body which ultimately contribute to problems such as depression, stress and obesity, all of which affect the brain’s ability to function well.

Dr Kerr says the more research that is conducted, the clearer it becomes how crucial a good diet is if you want a healthy brain.

“If you want to be alert and quick-thinking, don’t eat the junk or processed food because they will slow you down right now (as well as shrinking your brain long-term) and make you feel down and demotivated,” she says, succinctly summarising the science.

“Instead, eat the fibre, the plant food polyphenols, some wonderful omega 3s (fish) and fermented foods.”

Fermented foods such as kimchi are highly recommended.

Fresh vegetables and fruit of a range of different colours (including purple for anthocyanins – naturally occurring pigments with antioxidant properties), a variety of grains, good fats (avocado, grapeseed and olive oil, etc), fish, and probiotics/fermented foods all help nurture the brain. Fermented foods feed gut microbes and it’s no coincidence that the increased research in this area has resulted in more fermented food products and ferment-focussed cookbooks, with Adelaide preparing to host what is believed to by Australia’s first ferment festival in October.

If your diet is high in all these foods, Dr Kerr says, your body can actually cope with more junk food.

“If you eat polyphenols and you eat good food, then when you eat junk it doesn’t damage your brain or your body or your gut as much, because it can actually mitigate some of the really bad effects of junk food. But if you eat junk food and you don’t also eat good food, you’re in much bigger trouble.”

Much of Dr Kerr’s work relates to human-to-human interaction and she is keen to investigate her theory that combining a healthy diet with social interaction brings further benefits for the brain.

She says humans are “hard-wired to connect” and have always eaten together to bond.

“When I go and visit innovation hubs or highly innovative communities right through Europe and Asia and even in the US, certainly Scandinavia, one of the common things all of them have is a shared lunch room – so they come together and they eat.

“We know that when you get people together in an informal environment and they are connecting positively, they come up with creative ideas.”

In the so-called Blue Zone countries – five regions of the world with the highest concentration of centenarians – there is evidence to suggest that it is not just what residents eat, but how they eat that contributes to both longevity and brain health. In one of the areas, Ikaria in Greece, there is no dementia, and the countries all have low levels of depression.

“People in all five have gardens, they grow lots of their own food, they eat communally and they all eat lots of high fibre and polyphenols,” Dr Kerr says. “Most of them drink wine as well; they also all tend to dance and do cross-generational things as communities. But it’s really interesting how all of those areas also have minimal junk food.”

Dr Kerr believes many forms of social eating – such as families eating together or sharing meals with friends – can benefit the brain.

In her own household, shared family meals were a daily routine when her sons were growing up, with both contributing to the cooking from an early age.

“We always had a rule from the start: you couldn’t have a magazine or a book or any technology at the table. The table was to eat and talk; that was it. It was not negotiable.

“It [eating together] really is important not just for their bonding, but it’s this beautiful complex process that’s happening … you have much more of a tendency to cook and eat better food if you do it in a communal way like having a family meal at least once a day.”

Eating her words – Dr Fiona Kerr feeds her brain by:

• Starting the morning with warm water with lemon juice, followed by kefir.
• Trying to eat some type of crunchy fermented food – such as sauerkraut or kimchi – every day.
• Incorporating polyphenol-rich fresh foods into every family meal.
• Eating spicy food at least three times a week (chilli is a good anti-inflammatory).
• Buying sourdough rye bread (fermented) or baking it when she can, and eating oatcakes instead of white bread and crackers.
• Eating at least 70-per-cent-cocoa black chocolate every day.
• Having a good strong coffee before lunch.
• Primarily using good fats (usually plant – olive oil, avocado, etc) and eating nuts each day.
• Growing herbs, veggies, fruit and berries.
• Avoiding foods with emulsifiers and trans fatty acids (ie fast and highly processed foods).
• Shopping mainly around the edges of the supermarket (where you generally find fresh produce, meat and dairy).

Is Your Diet Making You Dumb? will be presented at the Open State Dome on October 3 as part of the festival’s Future Food program. Open State will run from September 28 to October 8, and is a festival of “innovation, collaboration, ideas and enterprise” with more than 100 events, workshops, and activations.