Depression is a debilitating chronic illness affecting 1 in 6 adults in the United Kingdom (UK) at any one time. Antidepressants and psychological therapy are the main treatments, but some people do not respond to these. Neurons and signals in the brain are greatly disrupted in people with severe depression. A ketogenic diet, a high-fat and very low-carbohydrate diet, supplies a form of energy that appears to help brain cells communicate and may improve the treatment of depression. Our goal is to find out whether a ketogenic diet could be an additional effective treatment for patients with depression for which antidepressants do not work. Using social media advertising, 100 patients, ages 18-65, who have previously tried at least two different antidepressant medications within the current depressive episode will be recruited. Enrolment, consent, and data collection will be collected online using self-report questionnaires. Participants will be allocated by minimisation 1:1 to the KD group or control group based on depressive severity (moderately severe vs. severe) and body mass index (\<30kg/m2 vs. 30+ kg/m2). The intervention group will receive 6-weeks of prepared ketogenic diet meals (3 meals with snacks per day) and weekly ketogenic diet-focused nutrition counselling. The control group will be asked to follow a diet to reduce their saturated fat intake and increase vegetable consumption by one portion a day. The control group will receive vouchers to assist with purchases and will be provided with weekly nutritional counselling. Existing treatment for depression will remain in both groups. The primary outcome is the change in depression symptoms at six weeks. All participants will complete assessments of depression and anxiety every two weeks, starting before treatment to post-intervention (week 6), and again at week 12. Additional outcomes include participants' ability to experience pleasure, quality of life, ability to socialise and work, cognitive processing, morning cortisol, and gut microbiome. At all stages of the study, adults with lived experience of depression will advise the research team to take into account the needs and views of patients. This study will provide evidence of whether following a ketogenic diet leads to a short-term improvement in depression in people whose depression cannot be relieved by antidepressants.
Age range
18 Years – 65 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
Patient Health Questionnaire (PHQ-9)
Timeframe: Baseline, 2 weeks, 4 weeks, 6 weeks (post-intervention), 12 weeks (follow-up)