‘Revolutionary’ diets come and go as fleetingly as the memoirs of the celebrities who endorse them. But one has outlived them all and could be set for a renaissance in neurological healthcare.

Long before wellbeing gurus told us about the ‘caveman’ (eat as much meat as you can) or the (I will only eat) ‘cabbage soup’, the ketogenic diet was born.

Its basic principle was to ramp up proportional fat intake against a combination of protein and carbs.

It was developed in the 1920s as an improvement on fasting as a treatment for epilepsy. After prevailing in the 30s and 40s, however, the dawn of anticonvulsant drugs pushed it into the shadows.

And here it largely stayed until Meryl Streep and Hollywood producer Jim Abrahams got together to make the movie First Do No Harm, in 1997.

Abrahams’ son had severe epilepsy that had been controlled by the ketogenic diet. Young Charlie was one of the many epileptic children for whom drugs did not work, where ketogenic diet therapy (KDT) did.

The movie shows lead character Robbie overcoming seizures and the horrific side-effects of medication simply through a change in diet. Suddenly the world wanted to know more about this high fat, low carb diet.

Campaigns followed and interest grew among parents, but 21 years later, it’s still being underutilised, especially here in the UK, says expert Sue Wood.

This could change, however, with renewed interest in the diet and scope to extend its reach into brain injury care and general neurological health.


Wood says: “There has always been around 30 per cent of individuals with epilepsy who don’t respond adequately or appropriately to anticonvulsive medication, or whose lives are blighted by its side effects.

“But when the drugs took over, experience and skills around the ketogenic diet declined. It’s very difficult to bring something back up to widespread usage when experience and skills disappear. In the UK, we have ketogenic therapy being delivered in all 39 of our main paediatric hospitals. But often people don’t get access to it until much further down 
the line.”

Wood is a specialist ketogenic dietitian at Matthew’s Friends, a charity focused on medical KDT which works alongside NHS KDT teams and offers information and support
for those on a medically supervised therapy.

It also runs its own KDT clinic and training courses for medical professionals interested in KDT.

At the heart of KDT is a reduction of carbohydrates.

This lowers the availability of glucose and the stimulus for insulin secretion – which, in turn, increases the rate of fatty acid oxidation in the liver and the release of ketones into circulation.

Brain tissue rapidly responds, using ketones as the primary fuel to drive energy metabolism. As with many areas of brain science, the exact link between the ketogenic diet and its anticonvulsant effect isn’t definitively understood.

However, it is widely believed that the diet boosts brain energy reserves and stabilises neuronal tissue. It also helps to balance neurotransmitters and various compounds involved in exciting and inhibiting electrical activity within brain tissue.

NICE guidelines recommend that the ketogenic diet is considered for children and young people with epilepsy whose seizures have not responded to “appropriate” anti-epilepsy drugs.

This is backed up by the results of a randomised trial in 2008 involving 145 children aged two to 16. Half were assigned to the diet, with the others put into a control group. Almost 40 per cent of those given the diet saw at least a 50 per cent reduction in seizures. Five children had a 90 per cent reduction.

Wood says: “A child is referred to specialist services, whether in a hospital or to ourselves at the charity. The specialist ketogenics team is run by a neurologist, a dietitian and maybe a specialist nurse. It only takes around three months of appropriately designed treatment to explore whether it will make a difference.

“Most people who reach KDT have been on many, many medications, none of which have produced the desired effect.

“Roughly a minimum of about 40 per cent are going to gain at least a 50 per cent reduction in seizures. This is a similar success rate to trying new anticonvulsive medication. But we do know that if you fail one drug, then a second and a third one, the next one has a much lower chance of working. The people who reach KDT have often failed several medications, so you have a very resistant group already. And, despite that, we still see that 40 to 50 per cent will get a reduction in seizures.”

Many adults also undergo KDT, but official recognition of its value beyond childhood is lacking.

“As far as adults are concerned, KDT services are emerging but there hasn’t been a randomised controlled trial conducted yet. There is lots of evidence supporting it but not at the level we have with children and
young people.”

In the first and largest study of ketogenic diet in adults, published in the US in 1930, over half achieved at least a 50 per cent reduction in seizure rates. More recently, meta-analysis of 12 relevant adult trials, incorporating 270 individuals, reported efficacy in 42 per cent of cases, showing parity with paediatric trials.

Almost half of these studies used a liberal version of KDT known as the modified Atkins diet. Further trials are needed, says Wood.

“KDT is effective in adults but there is not enough evidence. We use it in adults and yes we would say that the efficacy is comparable to children.”

KDT is not for everyone, however.
 “We are talking about something that is delivered under the control of the individual or their family, not under total medical control like taking a tablet. It’s something that you have to deliver within the home or
as an individual, so you have to be taught
and supported and trained in how to do that.

“That’s not the ideal situation for certain people but there obviously are a large number of people who would like the opportunity to explore it. That’s where our support, campaigning and trying to enable services comes into play.

“It’s not readily available in adult neurology departments. There are just pockets of availability, but they are limited and there is very little funding. The NHS has managed funds and the way to set up services for a treatment is to have randomised control trial evidence.

“That’s not there yet. If you’re trying to bring in a more novel approach, albeit from the 1920s, you have to jump through these hoops.

“Such trials have been promised in the past but have never happened. So, we are still waiting for them to take place anywhere in the world. It takes a lot of investment and funding to carry out these types of trials.”

For adults and children, evidence suggests that KDT goes far beyond seizure reduction in epilepsy. While increasingly linked to weight loss programmes, its relevance to serious diseases, including those of the brain, is also being recognised.

An influential paper (Paoli et al, 2014) reviewed evidence for KDT in treating neuromuscular and neurodegenerative conditions.

Although calling for more in-depth studies into the wider potential of the ketogenic diet, it noted that evidence suggests the mechanism of KDT could:

  • Provide an efficient source of energy
for the treatment of certain types of neurodegenerative diseases characterised by focal brain hypometabolism such as Parkinson’s and Alzheimer’s.
  • Decrease the oxidative damage associated with various kinds of metabolic stress. “If compared with glucose metabolism, ketones generate lower levels of oxidative stress in the brain together with a greater cellular energy output and antioxidant capacity,” it reported.
  • Improve “mitochondrial pathways” which can help to improve brain and neuronal metabolism.
  • Allow ketones to bypass the defect in mitochondrial activity founded in the skeletal muscle and spinal cord of Motor Neurone Disease patients.

Wood says: “There is work going on around the world looking at this in terms of a whole host of different neurological conditions, including brain injury.

“When you injure the brain or have a stroke, often the dysregulation of the fuelling of the brain is a component of that and causes part of the damage. The use of ketones, a fuel that can be used within the brain very easily, can serve as an alternative fuelling that can help cellular functions to 
be maintained and continued, for example if there is a dysfunction in glucose metabolism.

“It’s almost like putting in another fuel as a side-line. This is where ketogenics has really got to be properly explored in adults. Conditions like brain injury, Alzheimer’s and Parkinson’s all have a component of fuel dysregulation in the brain. Ketones could provide an alternative fuel and either modify the disease’s effects or navigate around the [problem areas]. Epilepsy is obviously key,
but there is also potential if it were to be explored, for KDT to be used in a wide range of brain conditions.”

As well as reducing seizure frequency, KDT can also lessen their intensity and shorten the recovery time needed afterwards.
But there are other positive spin-offs too. Adults in particular note greater clarity of thought and concentration, more energy and an upbeat mood.

“It’s not just about counting seizures. It’s about clarity of mind and feeling much stronger and fitter. Patients often feel much clearer in their head, even if they are still on medication.

“When we add it on top of the existing medication, patients can still get dramatic changes, even if they had felt lots of side effects from the drug. often it deals with brain fog – this sense of drugginess – as well as poor energy levels and concentration.

“Changing the fuelling of the brain can 
really alter all those aspects. The target is to control seizures but it’s the other dimensions that are really important to people. They obviously want to manage the seizures but aren’t necessarily fully aware of the disability they have on a daily basis from that general cloudy feeling. When brain fuelling is factored in, they can get this sharpness; that’s the payback for having to think carefully about what they are eating every day.

“A lot of people actually follow ketogenic diet plans simply for wellbeing now, although not to the level of detail used for epilepsy. It’s much more mainstream to eat lower carb diets and there are many recipes that people can choose to eat to be happy while doing it.”

For professionally delivered KDT, the following general principles apply:

  • A very low carbohydrate intake
  • An increased fat intake to provide adequate calories, replacing those lost through carbohydrate restriction
  • An adequate protein intake
  • Overall energy control to match individual requirements, delivering growth, weight loss or weight stability as required
  • Vitamin, mineral and trace element supplementation as required
  • Medical assessment and biochemical screening pre-therapy with reviews throughout treatment at three, six and 12 monthly intervals depending on the age/ wellbeing of the patient and stage of therapy

As Wood explains, it is not a DIY diet and must have input from professionals, initially at least.

“It is a therapy that needs to be carefully navigated. Having said that, some doctors may say ‘I think KDT would be good for you but we can’t refer you to anybody… Try it yourself’.

“People might get some benefits but they really need help and navigation to really optimise things, build their confidence and make sure they are doing it the right way.

“A lot of the people referred to it have got dysfunctions. If a child has complex epilepsy, for example, that might be part of whole host of disabilities and dysfunctions. We must make sure that we screen the individuals biochemically to make sure that they have the ability to adapt to metabolising fat. 
Most of us can do it and switch quite easily between using mainly carbs and fat, but there are those individuals who can’t. It’s very important that we don’t put someone on a ketogenic diet who, in fact, has some sort of abnormality in their ability to metabolise fat.

“The whole medical picture has to be
looked at, with the individual biomedically screened. If that’s all ne, we discuss the pros and cons of the treatment, including with the family, carers and the adults.

“Then you would train them for a couple of hours at least with an expert. This is based around the individualised prescription, enabling them to initiate the diet. It’s about controlling the mix of carbs, protein and fat instead of delivering them in a random fashion, altering fuel control in the brain.

“There are degrees of preciseness… There 
is a more liberal approach, where you really tightly control the carbs and you deliver plenty of fat but you don’t necessarily control the protein. That can work as well. We have to pick the right approach for the right person.”

As the 100th birthday of the ketogenic
diet approaches, Wood believes its role 
in neurological healthcare will become increasingly prominent, as long as access to the therapy improves.

From the 1920s when diet therapy prevailed to the subsequent drug-dominated years, “things are going to come full circle and we are going to have to go back to looking at nutrition very carefully,” she says.

“Nutrition is often left out in the NHS but is a very important part of disease management. We want KDT to be available to people who wish to explore it.
“Not everyone with epilepsy would jump at the chance to change their diet, but there are others who are desperate to change things and have been for years.
 It’s up to individuals and we want them to be allowed to explore it.

“We know that around 50 per cent of them will get a really good effect, if not more.”