Epilepsy, metabolic health, weight loss
Classic Ketogenic Diet
Very low carb, very high fat — run the body on ketones instead of glucose.
- Core restriction
- Carbohydrate under ~20-30 g/day
- Difficulty
- ●●●●●
- Check a food
- Open the food checker
A gentle reminder. This guide is for learning, not a prescription. Therapeutic diets interact with medication and conditions, so it's worth talking to your doctor or a registered dietitian before you begin.
A tidy few pages with the food lists, meal plan and reminders — good for the fridge door or the first appointment with your dietitian.
How it works
Cutting carbohydrate to roughly 20-30 g a day empties liver glycogen within a day or two. With glucose scarce, the liver converts fatty acids into ketone bodies — beta-hydroxybutyrate, acetoacetate and acetone — which cross the blood-brain barrier and fuel the brain.
The therapeutic version used in epilepsy clinics is prescribed as a ratio: 4:1 means four grams of fat for every combined gram of protein and carbohydrate. That is far stricter than the 'lazy keto' most people mean online.
Ketones appear to stabilise neuronal membranes, reduce glutamate excitability and shift the body away from insulin-driven fat storage. That single mechanism is why one diet shows up in seizure disorders, insulin resistance and some metabolic cancers research.
Nutrition at a glance
Therapeutic keto is weighed to a fat ratio; the everyday version below is the pattern most adults are given to start with.
- Carbohydrate
- 20-30 g/day
- Total, not net, in clinical settings
- Fat
- 70-80% of calories
- The bulk of every plate
- Protein
- 1.2-1.7 g/kg
- Enough to hold muscle, not so much it blunts ketones
- Fibre
- 20-25 g/day
- From low-carb vegetables, flax and chia
- Fluid and salt
- 2-3 L, 3-5 g sodium
- Ketosis flushes both faster than usual
Nutrients that often run short
- Potassium
- Magnesium
- Calcium
- Vitamin D
- Selenium
- Fibre
These are the ones worth planning for — through food where you can, and through a supplement your clinician suggests where you can't.
Key cautions
None of this is meant to frighten you off. These are simply the things that most often catch people out on this diet — the ones worth raising at your next appointment.
- Talk to a clinician
Diabetes medication needs adjusting first
Insulin and sulfonylureas can cause serious hypoglycaemia within days of cutting carbohydrate. SGLT2 inhibitors carry a risk of euglycaemic ketoacidosis on keto. Doses should be reviewed before your first low-carb day, not after.
- Talk to a clinician
Not a DIY diet for children with epilepsy
Ratio-based ketogenic therapy is prescribed and monitored by a ketogenic dietitian, with growth tracking and supplements built in.
- Worth testing
Lipids move in both directions
Most people see triglycerides fall and HDL rise; a minority see a sharp LDL jump. Test at baseline and again at three months.
- Worth testing
Kidney stones and bone density
Long-term ketogenic therapy raises stone risk and can affect bone density, particularly in children. Citrate supplements are often used preventively.
- Keep an eye on
The first two weeks feel rough
Headache, fatigue, cramp and constipation are usually salt, fluid and magnesium — not a sign the diet is failing.
Used for
- Drug-resistant epilepsy, especially in children
- Glucose transporter type 1 deficiency (GLUT1) and pyruvate dehydrogenase deficiency, where it is the primary treatment
- Type 2 diabetes and insulin resistance, under medical supervision
- Obesity and metabolic syndrome
- Under active research for migraine, PCOS and some neurodegenerative conditions
What to eat
Eat freely
Fats and oils
- Olive oil
- Avocado oil
- Butter and ghee
- Coconut oil and MCT oil
- Heavy cream
- Lard and tallow
Protein
- Eggs
- Beef, lamb, pork
- Chicken and turkey with skin
- Salmon, sardines, mackerel
- Shrimp and shellfish
Low-carb vegetables
- Spinach
- Zucchini
- Cauliflower
- Broccoli
- Asparagus
- Cabbage
- Lettuce and salad greens
- Cucumber
- Mushrooms
Other
- Avocado
- Hard cheeses
- Olives
- Bone broth
- Salt — you need more of it
Eat with care
Portion-controlled
- Nuts and seeds — macadamias and pecans are lowest in carbs, cashews are highest
- Berries — a small handful of raspberries or blackberries
- Tomatoes, onions, peppers, carrots
- Full-fat yoghurt and cottage cheese
- Sugar alcohols — maltitol raises blood glucose, erythritol and allulose mostly do not
- Alcohol — dry wine and spirits only, and tolerance drops sharply in ketosis
Best to skip
Grains and starch
- Bread
- Pasta
- Rice
- Oats
- Corn
- Potatoes
- Sweet potato
- Flour of any grain
Sugar
- Table sugar
- Honey
- Maple syrup
- Agave
- Fruit juice
- Soda
- Most sauces and dressings
Most fruit
- Banana
- Apple
- Grapes
- Mango
- Pineapple
- Dried fruit of any kind
Legumes
- Beans
- Lentils
- Chickpeas
- Peas
Three days of meals
Day 1
- Breakfast
- Three eggs scrambled in butter with sauteed spinach and mushrooms, half an avocado.
- Lunch
- Tuna salad with full-fat mayo on romaine leaves, olives on the side.
- Dinner
- Ribeye with garlic butter, roasted asparagus, side salad with olive oil.
- Snack
- A dozen macadamia nuts.
Day 2
- Breakfast
- Full-fat Greek yoghurt with a tablespoon of chia and six raspberries.
- Lunch
- Chicken thighs with skin over cauliflower rice fried in ghee.
- Dinner
- Baked salmon with lemon butter, zucchini noodles, parmesan.
- Snack
- Cheese cubes and a cup of bone broth.
Day 3
- Breakfast
- Bacon and eggs fried in the bacon fat, black coffee.
- Lunch
- Cobb salad — egg, bacon, avocado, blue cheese, olive oil dressing.
- Dinner
- Pork belly with braised cabbage and butter.
- Snack
- Two squares of 90% dark chocolate.
Getting started
- 1
Get a baseline. If you take insulin, sulfonylureas or blood pressure medication, talk to your prescriber first — doses often need to come down within days, not weeks.
- 2
Track carbs for the first two weeks. Guessing does not work; hidden carbs in sauces and 'low carb' products are the usual reason people never enter ketosis.
- 3
Salt aggressively. 3-5 g of sodium a day plus magnesium and potassium prevents most of what people call 'keto flu'.
- 4
Drink more water than feels necessary. Glycogen holds water; you lose several pounds of it in week one.
- 5
Give it three weeks before judging energy or performance. Fat adaptation is slower than ketosis.
Common mistakes
- Eating too much protein. Excess protein is converted to glucose and stalls ketosis, especially in therapeutic epilepsy use.
- Fearing fat. A low-carb, low-fat diet is just a hungry diet.
- Ignoring electrolytes and then blaming the diet for headaches, cramps and fatigue.
- Relying on keto bars and maltitol-sweetened sweets, which spike glucose for many people.
- Skipping vegetables entirely and ending up with no fibre, no potassium and a miserable gut.
FAQs
How do I know I'm in ketosis?
Blood ketone meters are the only reliable home method; 0.5-3.0 mmol/L is nutritional ketosis. Urine strips work for the first couple of weeks then stop being accurate as you get better at using ketones.
Is therapeutic keto the same as the keto I see on Instagram?
No. Clinical ketogenic therapy for epilepsy is weighed to the gram at a set ratio and supervised by a dietitian. Popular keto is a general low-carb pattern. They are not interchangeable when you are treating seizures.
Will it wreck my cholesterol?
It varies enormously between people. Some see triglycerides fall and HDL rise; a minority see a sharp LDL jump. Test at baseline and again at three months rather than assuming either outcome.
Can I do keto long term?
Many people do, but bone density, kidney stones and micronutrient status deserve periodic checks — particularly for children on therapeutic ratios.
Stacking with other diets
- Keto plus low oxalate is a real conflict: spinach, almond flour and chia are keto staples and oxalate bombs. Swap to cabbage, romaine, coconut flour and sunflower seed flour.
- Keto plus SIBO works well because both cut fermentable carbohydrate, but watch sugar alcohols and inulin-sweetened keto products.
- Keto plus renal diets needs supervision. Standard keto is protein and phosphorus heavy in ways CKD stages 3-5 cannot tolerate.