Question

I have read some internet discussions involving people with ME who claim to be finding benefits from using what is called the ketogenic diet. This is based on the idea that it is beneficial to switch to fats as the primary source of energy. However, I understood that glucose was the best source of ‘food fuel’ that we have. Has any research has been done in this area? And is this safe if you have ME?

Answer

Sue Luscombe, Hon. Dietetics Adviser, The ME Association:

Firstly, you are correct about glucose being the most used fuel in our body. And although fatigue and lack of energy are key symptoms of ME/CFS, to suggest that this can be improved by switching to obtaining energy from fats (i.e. the ketogenic diet) has not been proven and is only an interesting theory at present. Nobody fully understands what is going wrong in the body at a cellular level in ME/CFS. However, it is still useful for scientists to test treatment ideas like the ketogenic diet. This can help to increase our scientific understanding of the disease process, even when the results are negative.

Finding answers as to whether specific diets or nutritional supplements are helpful or not is also very useful when there are so many claims being made. On the downside, a ketogenic diet can often be harder to follow, more expensive, and takes more time and energy to prepare. It is also very restrictive, increases the risk of nutrient inadequacies, and produces some unpleasant side-effects such as bad breath (halitosis) and constipation. Plus we simply don't know if there are long-term problems or harm from following a ketogenic diet such as an increased risk of heart disease or cancer (through lack of potential balance, whole grains, and fruits or being high in fat content).

Some people claim a ketogenic diet helps with weight loss in the short term but rarely continues long term. The ketogenic diet is also being used as an NHS treatment under medical supervision for severe epilepsy in children. On the internet, there are many differences in opinion on diet – especially from practitioners of alternative, complementary or experimental medicine – which would not be recommended by mainstream medicine in the NHS.

The most accepted ‘best practice’ in terms of diet and laying the foundation for recovery in ME/CFS is one that is balanced and has a variety of foods and nutrients. So dietitians would not usually recommend a ketogenic diet for ME/CFS with the research evidence at present. The strongest evidence indicates that the healthiest option is a Mediterranean diet that is high in fruit (high carb) and vegetables, legumes, pulses, wholegrains, whilst reducing processed foods and not a restrictive ketogenic, high fat, low carb, diet.

See also:

• Diet and Nutrition: Malnutrition
• Diet and Nutrition: Restrictive Diets

More information

• The 2021 NICE Clinical Guideline includes a chapter, ‘Dietary Management and Strategies', and it recognises the risk of malnutrition and of getting expert advice particulary if the person is severely or very severely affected by ME/CFS. The ME Association has produced a free summary of the Guideline and recommend you familiarise yourself with the contents and then discuss the recommendations that are most relevant with your GP, ME/CFS Specialist Service, or Social Care provider (as appropriate).
• The ME Association has additional information available to download from the website shop:
  • A significant proportion of people with ME/CFS report that they also have stomach and bowel symptoms very similar to those found in irritable bowel syndrome (IBS). We examine the symptoms, explain how they should to be investigated, and discuss available treatments.
  • Diet and Nutrition – including dietary trends and malnutrition, and Cook Books with recipes for all tastes and abilities.
  • Vitamins and Supplements – including Vitamin B12 and Vitamin D deficiency and Muscle Energy Supplements.