Time-restricted eating as an adjunctive intervention for bipolar disorder

People with bipolar disorder often have disrupted sleep and body clocks, and no existing treatment directly targets these rhythms. Time-restricted eating—limiting food intake to a set daily window—has been shown to stabilise circadian rhythms in animals and humans, but it has never been tested in bipolar disorder. This project will run two studies. The first is a randomised controlled trial comparing time-restricted eating against a Mediterranean diet control, testing whether the intervention works best early in the illness. The second study will measure how adherence to time-restricted eating affects the daily amplitude of core clock gene expression and melatonin secretion, and how those biological changes relate to symptoms and quality of life. If successful, this work would provide a simple, low-cost, and highly acceptable intervention for bipolar disorder that patients could adopt without medication changes. It would also deliver a critical test of the circadian rhythm hypothesis of bipolar disorder—a long-standing theory that has never been directly examined through an intervention that shifts the body clock. The research is fundamental in nature: it asks whether stabilising daily biological rhythms can improve mental health, a question with implications for how we understand and treat mood disorders more broadly.