STRESSED Queenslanders can eat themselves happy, ­according to a psychologist turned brain nutritionist.

After decades of research, Delia McCabe claims that therapists have more chance of helping people with mental health problems if the patients have well-fed brains.

"It's hard to make a malnourished brain happier. Ongoing research links better diets with better mental health," she said.

Ms McCabe turned her back on conventional "talking" therapy to concentrate on a masters in nutrition neuroscience.

"Trying to talk to a client seemed like a second step to be attempted after making sure their diet was supporting their brain," Ms McCabe said.

The brain is sensitive and susceptible to nutrient deficiencies, excesses and poor diet. At least three million Australians are living with anxiety or depression.

"Modern life, with increasing demands on time-poor people, along with out-of-control environmental and political challenges, means that our busy brains are battling to find equilibrium," she said. "A malnourished brain finds it even harder to stay balanced. I'm not saying that psychotherapy is not useful - it is very useful."

Ms McCabe said it was important to consume whole, fresh, unprocessed foods that naturally contain loads of colour. Also look for cold-pressed fats and oils and avoid fried and baked goods that contain cheap, damaged, toxic fats and oils, as well as highly refined carbohydrates. Water is the best drink and excess coffee is out.

Brisbane clinical psychologist Dr Judith Locke says a change in diet is not a priority over professional psychological assessment and treatment.

"Assessing the client's situation, understanding contributing factors, communicating that to the client and then giving them evidence-based treatment to overcome the issue, typically in changing and altering their unhelpful behaviours and reactions - that is more beneficial," she said. "Eating more vegetables will not solve a person's long-term social anxiety or PTSD."

HAPPY FOODS

Dark chocolate

Colourful fruit and veg, green veg and leaves

Nuts and seeds

Cold pressed extra virgin olive oil

Cold water fish like salmon

Quinoa and millet, lentils and chickpeas

Fresh herbs

Goji, camu camu, maqui berries