The ketogenic diet restricts carbohydrates to under 50g per day (often 20-30g), forcing the liver to produce ketone bodies from fat as an alternative fuel. Originally developed in the 1920s for drug-resistant epilepsy (where it remains a clinical treatment), it has been widely adopted for weight loss. Initial weight loss is fast (partly water weight from glycogen depletion). Long-term data beyond 2 years is limited; concerns include LDL cholesterol elevation, kidney stress and nutrient deficiencies. Type 2 diabetes management under medical supervision is a well-supported use case.
Key points
- Under 50g carbohydrates per day
- Liver produces ketones from fat
- Medical use: epilepsy, diabetes management
- Limited long-term safety data beyond 2 years