Ketogenic diets and fasting are different practices. A ketogenic diet substantially restricts carbohydrate intake and changes the balance of dietary fats, protein and carbohydrate. Fasting involves going without food for a period of time; intermittent fasting alternates fasting periods with periods when eating is allowed. Combining the two is not an established treatment for an eating disorder and should not be presented as a cleansing program.
Editorial correction: This page previously provided restrictive schedules, appetite-suppression tips and claims about increased cleansing. Those instructions and claims have been removed. This article explains the distinction between specialist dietary treatment and a general weight-loss trend.
When a ketogenic diet has a medical role
NICE epilepsy guidance describes situations in which a ketogenic diet may be considered under a tertiary epilepsy specialist. Such treatment is planned and monitored for a particular clinical purpose. It is not equivalent to starting a diet from a celebrity account, buying a supplement or combining fasting rules found online.
A specialist team considers whether the diet is appropriate, how nutritional needs will be met, how medicines fit the plan and how progress or adverse effects will be monitored. Evidence for one medical use cannot simply be transferred to claims about general mental health, detoxification or every other condition.
Why an eating-disorder history changes the discussion
Rigid food rules can become part of a distressing cycle of restriction, preoccupation and loss of control. A person may describe a plan as healthy while finding that it makes social meals, concentration or day-to-day life increasingly difficult. The reason for seeking support is the pattern and its effect, not whether someone looks a particular way.
NICE guidance for binge-eating disorder includes regular meals and snacks within treatment and advises against trying to lose weight by dieting during treatment because it can trigger binge eating. An online fasting plan can therefore conflict directly with an individual’s care plan.
Questions to ask before changing your diet
What problem is the change intended to address? What evidence applies to that specific problem? Is there a less restrictive option? Could the plan conflict with an existing illness, medicine, pregnancy or current treatment? Who will help monitor its effects, and what would be a reason to stop and seek advice?
If you have an eating-disorder history or concerns about your relationship with food, discuss the idea with an appropriately qualified clinician and dietitian before beginning. Do not change a prescribed therapeutic diet without speaking with the team responsible for it. If you have diabetes, speak with your diabetes team before fasting or substantially restricting carbohydrates. Insulin and sulfonylureas can cause hypoglycemia (low blood glucose), and fasting or carbohydrate restriction can increase this risk. People with type 1 diabetes also face a risk of diabetic ketoacidosis. SGLT2 inhibitors can increase ketoacidosis risk, particularly with restricted food intake or dehydration, even when blood glucose is not very high. Do not stop, reduce or otherwise change diabetes medicines on your own; agree any adjustments and monitoring with your diabetes team.
Signs that support would be useful
Seek an assessment if food rules are becoming increasingly rigid, eating brings persistent guilt or fear, you repeatedly feel unable to control eating, or attempts to compensate are affecting your health. The NIMH overview of eating disorders explains that serious difficulties can occur at different body weights.
Fainting, severe weakness, chest symptoms or an inability to maintain fluids need urgent medical assessment. New confusion, sudden chest pain that does not go away, or difficulty breathing require immediate emergency medical help. You do not need to complete a diet or reach a particular weight before asking for help.
