How to do it
- Doctor first if you've been low for weeks. In the trial the food was an add-on to care, not the care.
- Ask about a dietitian. The trial's change was led by one, not done alone.
- Mediterranean-style is the direction. What that means on your plate is the dietitian's job.
- Give it weeks. The trial ran twelve.
What the trial did
- Poor dietthe starting point
The trial took adults with major depression who were already eating badly. People with a decent diet weren't tested.
- Dietitianleads the change
One group got dietitian-led help towards a Mediterranean-style diet. The other got social support. Most were already on medication or therapy, and kept it.
- Symptomsfell further
At 12 weeks, depression scores had fallen further in the diet group than in the support group.
- Youadd, don't swap
One small trial, as an add-on to treatment. A reason to fix the food as well, not instead.
Why it works
In one trial, adults with major depression who were eating badly got 12 weeks of dietitian-led help towards a Mediterranean-style diet, most on top of medication or therapy they already had. Their symptoms fell further than in a group given social support instead. Evidence: decent
It's one small trial. That's why the do-line says doctor first, and food as well. Evidence: decent
The long readEvery step of the chain, each study with its numbers, and what's still unproven. 2 min read.
What happens in your brain
I can't give you the route from plate to mood from this evidence. The chain is what the trial did.
A poor diet to start with. The 67 adults in the trial had major depression and were already eating badly. Evidence: decent
A dietitian leads the change. One group got dietitian-led help towards a Mediterranean-style diet; the other got social support. Most were already on medication or therapy, and kept it. Evidence: decent
Symptoms fall further. At three months, the diet group's depression scores had fallen further than the support group's. Evidence: decent
You add, you don't swap. The trial tested diet on top of treatment, not in place of it. Evidence: decent
The proof
- The SMILES trial, 2017: 67 adults with major depression and a poor diet were randomly given 12 weeks of either dietitian-led diet support or social support. 55 of them were already on medication, therapy or both. Evidence: decent
- At three months, the diet group had improved more, with a standardised effect of 1.16, a large one. Evidence: decent
- It's a single small trial, and only the assessors were blinded: people knew which group they were in. Evidence: decent
How to do it
- If you've been low for weeks, start with your doctor. See two questions, then a doctor.
- Ask about a dietitian at the same visit. In the trial the change was dietitian-led. Evidence: decent
- Mediterranean-style is the direction the trial took. Evidence: decent What that means for you is the dietitian's call.
- Give it weeks, not days. The trial ran twelve. Evidence: decent
Watch out
One small trial of 67 people, all eating badly to begin with, who knew which group they were in. Evidence: decent If your diet is already decent, or you're having a flat week rather than depression, this wasn't tested. Evidence: decent
Food is not a replacement for treating depression. In the trial, most people were already on medication or therapy and stayed on it. Evidence: decent