How Your Diet Secretly Shapes Your Mood and Mental Health

The foods we eat may have a far greater impact on our mood than many realise. Research now shows that whole grains, beans and lentils can lift spirits by feeding gut bacteria, while ultra-processed foods and refined carbs may worsen anxiety and depression. Experts say these findings are reshaping how we think about mental health and diet. For years, people have linked comfort foods like sweets and fast food with happiness. But Felice Jacka, director of the Food and Mood Centre at Deakin University, argues this belief comes from advertising—not science. Her work, starting with a 2010 study published in the American Journal of Psychiatry, revealed that women eating healthier diets had lower rates of depression and anxiety. Over 15 years, her research helped move nutritional psychiatry from a niche idea to a recognised field.

Large studies now confirm that diets high in ultra-processed foods and refined carbohydrates raise depression risk by 20 to 30 percent. These foods can leave people feeling anxious, irritable or sluggish just hours after eating. Randomised trials also show that cutting back on processed items and eating more whole foods can ease depression symptoms.

The key may lie in the gut. Foods rich in fermentable fibre—like whole grains, beans and lentils—feed beneficial gut bacteria, which in turn produce compounds that improve mood. Dr. Meroé Morse and Hannah Holscher highlight that these plant-based foods act as fuel for microbes linked to emotional wellbeing. When gut bacteria thrive, studies suggest, so does mental health. The evidence is clear: swapping processed snacks for whole grains, pulses and minimally processed meals could help stabilise mood and lower depression risk. Clinicians, schools and even prisons are now adopting dietary changes as part of mental health strategies. With global workshops like the 2026 Food & Mood Masterclass on the horizon, the connection between food and mental wellbeing continues to gain ground.