Dietary therapies (ketogenic and related diets)
Medical diets — ketogenic, modified Atkins and low-glycaemic-index — are powerful, evidence-based treatments for drug-resistant epilepsy; others, like gluten-free, are more limited.
Some diets are genuine medical treatments, not lifestyle choices. The classic ketogenic diet and its variants are well-established, evidence-based options for drug-resistant epilepsy, and are first-line for a few specific conditions. They must be medically supervised by a team including a dietitian. Other dietary approaches, such as gluten-free/casein-free diets for autism, have much weaker evidence.
At a glance
- Strongest use
- Drug-resistant epilepsy (incl. some specific syndromes)
- Main diets
- Classic ketogenic, modified Atkins, low-glycaemic-index
- First-line for
- GLUT1 deficiency and pyruvate dehydrogenase deficiency
- Supervision
- Always medically supervised, with a dietitian
- Gluten-free/casein-free
- Weak evidence outside coeliac disease
How ketogenic-type diets work
Ketogenic diets are high in fat and low in carbohydrate, shifting the body to burn fat for fuel and produce ketones. This change in brain metabolism has a genuine antiseizure effect for many children, especially when several medicines have failed. These are precise medical diets, calculated and monitored by a specialist team, not simply 'low-carb eating'.
The main variants
- Classic ketogenic diet — the most stringent, with carefully weighed fat-to-carbohydrate ratios; often used in younger children and via feeding tubes
- Modified Atkins diet (MAD) — less restrictive, no weighing or fluid limits; often suits older children, teenagers and families wanting more flexibility
- Low-glycaemic-index treatment (LGIT) — allows more carbohydrate but only low-glycaemic-index foods; the least restrictive medical option
- MCT (medium-chain triglyceride) variants — use a particular type of fat to allow more carbohydrate
Where diets are used
Dietary therapy is a recognised option for drug-resistant epilepsy across many syndromes (including Dravet syndrome, Doose syndrome, Lennox–Gastaut syndrome and infantile spasms). For two specific conditions — GLUT1 deficiency syndrome and pyruvate dehydrogenase deficiency — the ketogenic diet is the first-line, primary treatment, because it directly addresses the underlying metabolic problem.
Practicalities and cautions
Because these diets change metabolism, they need supervision: a dietitian calculates and adjusts the plan, supplements vitamins and minerals, and the team monitors growth, blood tests, kidney stones, cholesterol and other effects. They are demanding for families, so support and realistic planning matter. Diets are introduced and stopped gradually, never abruptly.
Ketogenic-type diets are medical treatments and must be supervised by an epilepsy team and dietitian — not started alone, because of risks to nutrition, growth and metabolism.
Diets for autism and other uses
Gluten-free/casein-free and other elimination diets are popular in autism, but the evidence for improving core autism features is weak, and unsupervised restriction can harm nutrition. They are clearly indicated only where there is a specific medical reason (such as coeliac disease). Any restrictive diet in a child is best discussed with a clinician and dietitian.
How an educational review can help
An educational review can explain whether a dietary therapy is a realistic option for a particular epilepsy, which variant might suit a family, and how the evidence applies — helping you prepare questions for your treating team and dietitian. It is educational and does not replace your clinician's care.
Selected sources
- International consensus guidelines on the optimal clinical management of children receiving dietary therapies for epilepsy.
- Evidence for ketogenic diet as first-line treatment in GLUT1 deficiency and pyruvate dehydrogenase deficiency.
Last reviewed: 2026-05-22
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