Fasting and epilepsy

Fasting can be for religious reasons. But it has also become popular in recent years. Many people believe it is good for their health but how may it affect people with epilepsy?

What effect does fasting have on epilepsy?

Fasting is when someone doesn’t eat for a period of time and it can sometimes involve not drinking either. People may decide to fast for a number of reasons:

• for religious reasons;
• before they have an anaesthetic or a blood test;
• because they believe it has health benefits; or
• to lose weight.

If you are thinking of fasting, it is important to think about what your own triggers may be and how your epilepsy affects you. You should also speak to your neurologist, epilepsy specialist nurse (ESN) or GP so that they can advise you if it is right for you and how to do so safely.

People with epilepsy may be able to fast successfully but there is a lack of clear evidence about how safe fasting is for people with the condition. More research needs to be done. Risks for people with epilepsy when fasting may come from:

• changes in your routine, for example when you take your anti-seizure medication (ASM);
• fatigue or tiredness; or
• lack of sleep or disturbed sleep.

Fasting for religious reasons

Religious fasting is practised by a number of faiths such as Islam, Hinduism, Buddism, Christianity, Judaism, Jainism and Taoism, although each religion may fast in different ways.

During Ramadan, the ninth month of the lunar Islamic calendar, adult Muslims do not take any food, drinks, or oral medications from dawn to sunset. But Islamic law does say that you do not need to fast if it might cause you harm, for example by making your epilepsy worse. 

Research has been done on people with epilepsy fasting during Ramadan. But this research has had mixed results.

One study found that some people who had myoclonic, absence or focal seizures had fewer seizures while fasting during Ramadan. The study showed no effect on tonic clonic seizures and suggested that people with these seizures need to put extra precautions in place if they do fast, such as making sure to get enough sleep. This research did not recommend fasting for people with drug-resistant epilepsy. This is when two or more anti-seizure medications have been tried but have failed to bring seizures under control.

Another study found that some people with epilepsy had fewer seizures while fasting during Ramadan and for a month afterwards but it did not say which seizure types they had. 

Anyone considering fasting for Ramadan should discuss this with their medical professional to make sure they can fast safely.

Fasting before an anaesthetic

If you are having surgery that requires an anaesthetic your doctor is likely to advise you to avoid eating and drinking for a period of time beforehand. This is to avoid the chance that you may be sick during the surgery. You may also be asked to fast before a blood test. 

In either case, you should be given clear instructions about what to do. But it is a good idea to tell the medical professionals about your epilepsy. You can then discuss with them what to do about fasting and taking your ASM before the surgery or the blood test. 

Fasting for health benefits or to lose weight

There is no evidence to prove that fasting can definitely help you to lose weight or that it has health benefits, although some people think it is helpful. One study has shown that periods of fasting (intermittent fasting) can have benefits on the brain and brain disorders, including having seizures. But this research was carried out on animals and more research needs to be done on humans. 

For some people, missing meals may be a trigger for their seizures. At the moment, there isn’t enough evidence to say if this is a risk or not.

If you want to try fasting for health benefits or if you want to try a diet that involves fasting, it is important to speak to your neurologist, ESN or GP about what the risks may be for you personally. They may be able to help you come up with a plan to do so safely.

Epilepsy Society is grateful to Dr F J Rugg-Gunn, Consultant Neurologist & Honorary Associate Professor, Clinical Lead, Chalfont Centre for Epilepsy, who reviewed this information.

Information produced February 2025. Review date February 2027.