General description of the ketogenic diet
The ketogenic diet was first used as a treatment in 1921 . It aims to mimic the effects of fasting, using fat as the major energy source leading to the production of ketone bodies. It is effective for myoclonic, focal and temporal lobe epilepsy. The exact mode of action has still to be elucidated [2,3].
The ketogenic diet is often the last line of treatment for children with intractable epilepsy. When high levels of anti convulsants have proved unsuccessful the ketogenic diet can provide an alternative, or it can be used with a prescribed drug regimen. A ketogenic diet may also be useful if anti convulsant drugs cause unpleasant side effects .
Criteria for patient selection
The diet appears to be most successful in children with myoclonic epilepsy, major motor epilepsy (grand mal) and minor motor epilepsy. Children aged from 6 months to 16 years have been shown to be receptive to this type of treatment, although greater success has been described in the younger age range .
The regimen is a difficult one and the implications of the diet should be explained to parents; there must be considerable commitment from the parents and the dietician, and parents should express a willingness to co-operate before the diet is constructed. This diet should be commenced in hospital with appropriate monitoring and teaching and usually requires an admission of up to five days.
A diet history should be taken to obtain meal patterns, food preferences and current energy intake. Very fussy eaters are unlikely to be able to comply with the dietary restrictions, as are children who dislike fatty foods.
Details of current fluid intake should be sought; a high intake (more than 1-1.5l daily) is contraindicated on this regimen.
It is often advisable to begin with a short fast (about 12 hours) before commencing the diet, so that ketosis is more readily achieved.
Restricted foods both in the hospital and at home should be weighed.
No sweet foods or sugar are allowed.
No foods other than those on the diet sheet are allowed.
Unrestricted foods are listed in Table 1. Sufficient unrestricted foods must be available within the diet to provide bulk and alleviate hunger.
The fat intake should be spread fairly evenly throughout the day; this is particularly important if a special milk is used.
Snacks in between meals should be discouraged as they impair ketone production.
In regimes using medium chain triglyceride (MCT) emulsion, the Liquigen should be diluted with at least an equal volume of other fluid.
MCT should be introduced gradually to avoid abdominal discomfort and diarrhoea. In small children this may be in 5 - 10g (10- 20 ml Liquigen) increments. Older children may tolerate a more rapid introduction, giving one quarter strength feeds on day 1, half strength on day 2, three quarters on day 3 and full strength on day 4
A full vitamin and mineral supplement (e.g. Forceval Junior Capsules plus calcium) must be given to ensure that nutritional requirements are met.
All medicines and tablets should be carbohydrate free.
Table 1 Unrestricted foods in ketogenic diets
|Drinks||Tea and coffee (no milk or sugar), sugar-free drinks,
diabetic squash mineral water
Do not use drinks containing sugar, glucose or fructose
|Salad vegetables||Celery, chicory, cucumber, lettuce, spring onion, tomato, watercress|
|Green vegetables||Broccoli, brussel sprouts, cabbage, carrots, cauliflower,
courgettes, green and runner beans, leeks, marrow, mushrooms, onions,
Potato, peas, beans and lentils are restricted
|Fruit||Rhubarb, stewed without sugar|
|Flavourings||Salt, pepper, herbs, spices, vinegar, oil and vinegar dressing, beef extracts, yeast extract, Worcester sauce, food essences and colourings, gelatine and sugar-free jelly|
|Artificial sweeteners||Aspartame and saccharine based sweeteners
Do not use sweeteners containing sucrose. glucose, lactose or fructose
Which ketogenic diet?
The same principle is common to all regimens, in that they are high in fat, low in protein and carbohydrate. All calculations are based on the child's actual body weight unless the child is obese, when it may be preferable to use the ideal weight for height to prevent exacerbation of the obesity .
Four types of diet can be used:
- the 4:1 classical ketogenic diet
- medium chain triglyceride diet
- John Radcliffe diet
- Great Ormond Street diet
The classical ketogenic diet
return to UK ketogenic diet protocols
(update 1.2: 9 November 2002)
(issue 1: 23 December 1997)