Ketogenic Diet for Treatment-Resistant Depression: Dietary Interventions for MEntal Health Study (DIME)

"A Ketogenic Diet (KD) is a high-fat and very low-carbohydrate intake. Participants will follow a modified KD (estimated 20-50g carbohydrates/day based on a 2000 kcal diet) without energy restriction. Participants will test for ketosis in their morning urine at least twice a week to monitor adherence.~To support adherence in people with depression, delivered pre-prepared KD meals (3 meals per day) and additional ketogenic snacks will be sent to participants. A registered dietitian will provide weekly 30-minute nutritional counselling sessions. The dietitian will schedule appointments and assess the participants' experience with adhering to the KD diet, troubleshoot as required, give guidance on how to prevent or overcome side effects of KD diets, and keep record of participants' ketosis level and suicide risk."

Participants in the control group will receive the same degree of dietetic input and be told that their diet is a modified fat and phytonutrient diet. The photo diet aims to increase vegetable consumption, reduce saturated fat intake and increase poly- and mono-unsaturated fat intake. Participants in the control group will receive food vouchers (£20 every two weeks) to help purchase these items. This aims to be a plausible placebo dietary treatment for depression. There is no clear evidence that these manipulations will change depression severity. The dietitian will create written materials to explain the diet and suggest foods by colour with supporting recipe suggestions.