Table 1.

Participant eligibility.

Inclusion criteria

Exclusion criteria

To be eligible for this study, an individual must meet the following criteria: Have been diagnosed by a psychiatrist with either schizophrenia, schizoaffective disorder, or Bipolar Affective Disorder and have had the condition for at least 6 months. Being clinically stable (no episodes of hospitalization or significant treatment changes for at least 3 months) Possess the mental capacity to provide informed consent and willingness to sign a written informed consent document. Aged ≥18 years old. Able to understand the basic principles of the specific diet and follow dietary instructions as provided by the study dietitian. Willingness to adhere to all study procedures including the completion of an accurate diet and symptoms diary, daily blood glucose and ketone monitoring, and to attend the visits as scheduled.

Individuals who meet any of the following criteria will be excluded from participation in this study: Pregnant, breastfeeding, or planning to become pregnant within 3 months. Active substance misuse with alcohol or illicit drugs. Use of the ketogenic diet in the previous 2 months. Currently following a vegan diet. Admission to a mental health hospital within the past 3 months. Inability to complete visits and assessments. Uncompensated cardiovascular disease. Severe hyperlipidemia. Type 1 diabetes. History of eating disorder. BMI < 18.5 kg. On medication that can cause ketosis. Not willing to change diet or unable to change diet due to medical reasons. Active liver or kidney disease. No access to cooking facilities and ingredients to prepare recipes following the specific diet. Current involvement in another research study.