Food and Mood

Everyone knows the feeling. A proper meal after a long day, and the world looks a bit brighter. Skip lunch, and by three o'clock everything is annoying. Scientists have spent the past couple of decades asking whether the link between food and mood goes deeper than that, and the answers are interesting. They're also more modest than the headlines. Here's what the research says, what it doesn't, and how to use it without turning dinner into a chore.

The short version

Eating patterns rich in vegetables, fruit, whole grains, legumes, nuts, fish and olive oil are linked with lower rates of depression ¹³.
One small Australian trial found that improving diet helped people with depression, alongside their usual treatment ².
Most of the evidence shows a link, not proof of cause, and some trials found no effect ³⁴.
Food can support mental health. It does not replace medical care.

What the studies show

Healthy eating patterns are linked with lower depression

In 2019, researchers pooled 41 studies on diet quality and depression in the journal Molecular Psychiatry ¹. The strongest signal was for the traditional Mediterranean diet. In four long-term studies, people who followed it most closely were about a third less likely to develop depression than those who followed it least ¹. Eating patterns low in inflammatory foods showed a similar link ¹.

The authors were careful: this evidence comes from observational studies ¹. People who eat well may also exercise more, sleep better, earn more or have more support. Researchers try to adjust for those things, but they can't rule them all out.

The SMILES trial

To test cause and effect, you need a trial. In 2017, a team led by Professor Felice Jacka at Deakin University published the SMILES trial in BMC Medicine ². Sixty-seven adults with moderate to severe depression were randomly assigned either to seven sessions with a clinical dietitian or to a social support group of the same length, on top of their existing treatment ².

After 12 weeks, the diet group improved significantly more. About a third of them (32%) reached remission, compared with 8% of the social support group ².

That's encouraging. It's also one small trial, with 67 people and dropouts along the way, and participants knew which group they were in. It needs repeating in bigger studies before anyone calls diet a treatment.

And a trial that found nothing

The MooDFOOD trial, published in JAMA in 2019, followed 1,025 overweight adults in four European countries who had some depressive symptoms but no recent depression ⁴. It tested nutritional supplements and a food-focused behavioural therapy as ways to prevent major depression. Over a year, neither one made a meaningful difference ⁴. A good reminder that results in one group, with one approach, don't automatically carry across.

Why food might matter

A 2020 review in The BMJ by Joseph Firth and colleagues sums up the leading ideas ³:

Blood sugar. Big swings from sugary, refined foods may affect how you feel.
Inflammation. Some eating patterns, like the Mediterranean diet, may reduce inflammation, which is linked with depression.
The gut. The bacteria in your gut talk to your brain, and what you eat shapes those bacteria.

The review's conclusion is honest: more research is needed to understand these links and to work out how and when nutrition can improve mental health ³.

What this means in your kitchen

None of this needs special foods, supplements or rules. It looks a lot like the Australian Dietary Guidelines ⁵: plenty of vegetables, fruit, whole grains and legumes, some protein foods and dairy or alternatives, and fewer highly processed foods and sugary drinks. Some easy ways in:

Cook with beans and lentils. A pot of dal or hummus is cheap, filling and full of fibre.
Make vegetables the hero. Try moussaka, Greek salad or a quick stir-fry.
Use olive oil. It's the backbone of Mediterranean cooking. Read more about olive oil.
Keep nuts handy. A handful of walnuts or almonds is an easy snack.
Try fermented foods. Kimchi, yoghurt and miso add flavour and live cultures.
Eat regularly. Long gaps leave many people tired and cranky. Our healthy breakfasts and healthy snacks can help.
Watch the alcohol. The NHMRC advises healthy adults to drink no more than 10 standard drinks a week and no more than 4 on any day ⁶.

Be kind to yourself

When you feel low, cooking can feel impossible. That's normal. A tin of beans on toast, a bowl of fried rice or a piece of fruit is enough. Comfort food has its place too; see our comfort food collection. And eat with others when you can.

Getting help

If your mood has been low for more than a couple of weeks, talk to your GP. Food can be part of looking after yourself, but it isn't a substitute for proper care. If you need to talk to someone now, call Lifeline on 13 11 14 or Beyond Blue on 1300 22 4636. In an emergency, call 000.

Sources

Lassale, C. et al., "Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies", Molecular Psychiatry 24, 965–986, 2019. https://www.nature.com/articles/s41380-018-0237-8
Jacka, F. N. et al., "A randomised controlled trial of dietary improvement for adults with major depression (the 'SMILES' trial)", BMC Medicine 15, 23, 2017. https://doi.org/10.1186/s12916-017-0791-y
Firth, J. et al., "Food and mood: how do diet and nutrition affect mental wellbeing?", The BMJ 369, m2382, 2020. https://pmc.ncbi.nlm.nih.gov/articles/PMC7322666/
Bot, M. et al., "Effect of multinutrient supplementation and food-related behavioral activation therapy on prevention of major depressive disorder among overweight or obese adults with subsyndromal depressive symptoms: the MooDFOOD randomized clinical trial", JAMA 321(9), 858–868, 2019. https://doi.org/10.1001/jama.2019.0556
National Health and Medical Research Council, Australian Dietary Guidelines, Eat For Health. https://www.eatforhealth.gov.au/guidelines
National Health and Medical Research Council, "Alcohol". https://www.nhmrc.gov.au/health-advice/alcohol