Who benefits from a ketogenic diet?

Written by: Dr Abbi Lulsegged
Published: | Updated: 22/05/2023
Edited by: Emily Lawrenson

You’ve likely heard of the ketogenic diet – most diets have their day in the sun at one point. Maybe you, or a friend, has thought of trying out this low-carb diet as a means of losing weight, but did you know the ketogenic diet can also help with symptoms of diabetes, polycystic ovary syndrome, and even epilepsy? Dr Abbi Lulsegged, expert consultant endocrinologist, tells us how.

What's the ketogenic diet?

The ketogenic diet, sometimes known as keto, is a diet which is very low in carbs. When you eat food high in carbs, your body produces insulin and glucose in response. Glucose is converted and used as energy, and insulin processes the glucose in your bloodstream, sending it around the body. As glucose is the easiest molecule for the body to convert into energy, it will always be first choice as a primary energy source – meaning fat is not needed, and is stored.


The word ‘ketogenic’ relates to ‘ketosis’, which is the natural process which the body kicks into action when faced with low food intake, in order to survive. This then produces ‘ketones’, broken down from fat in the liver. If the body is deprived of carbohydrates and confronted with fats, it will start to burn the ketones rather than glucose as its source of energy. When ketone levels are optimal, our body sees the results through health and weight loss benefits.



What can the ketogenic diet control?

The ketogenic diet essentially turns your body into a fat-burning machine, by forcing your body to use fat as an energy source. This means it can help you to lose weight, not through reduction in calories, but through reduction in carbohydrates.


The ketogenic diet isn’t simply used to help with weight loss, however. People die specifically from obesity-related conditions rather than being overweight per se. It is therefore important to appreciate that targeting the weight around the middle might also control other obesity-related issues including: 

  • fatty liver,
  • low testosterone levels related to excess weight around the middle;
  • reactive hypoglycaemia;
  • diabetes; 
  • obesity-related cancers, and;
  • some forms of dementia.



How are diabetes and the ketogenic diet connected?

The ketogenic diet can help in lowering your glucose levels (blood sugar levels), which is the aim of many treatments for diabetes. Elevated glucose levels can cause inflammation in the nerves and blood vessels, which is where diabetes-related problems stem from. If you don’t have diabetes, insulin helps to regulate glucose and keep it at a normal level. In those with diabetes, this function doesn’t work correctly. Glucose can come from the carbs that we eat, so if the amount of carbs consumed is lower, then the body logically finds it easier to control blood sugar levels.


In those with type 2, the ketogenic diet can provoke a total reversal, and glucose levels can be normalised again. However, this often needs to be combined with intermittent fasting for long-term control.



How are PCOS and the ketogenic diet related?

Polycystic ovary syndrome (PCOS) is a health problem affecting hormone levels in women, along with their ovulation and periods. In turn, this can affect fertility, and pregnancy.

In those with PCOS, cells in the body do not respond as they should to insulin, meaning a resistance develops. As the body needs insulin to help glucose enter cells, the body needs higher levels of insulin to process this.

Therefore, a low carb diet can be beneficial to those with POCS, as it can help to lower levels of insulin and treat the resistance to it.



How can the ketogenic diet help epilepsy?

Epilepsy results in seizures, through an excess in brain activity. Usually, epilepsy patients are given drug treatments or therapy, but some do not respond well to this. Higher ketone levels can result in improved seizure control, either in frequency or severity.



What kind of food can be eaten on the ketogenic diet?

There are no real rules to the ketogenic diet, except to limit the amount of carbohydrates that you consume. Grains such as wheat, cereal, or corn, are generally avoided, along with sugar, and certain fruits (apples, bananas, kiwis etc).



Can anyone try the ketogenic diet?

With diet and lifestyle, most boils down to personal choice. However, when the ketogenic diet is prescribed as a method of treatment, it is best to consult a physician or specialist, as the ketogenic diet can not only be difficult for some to follow, but it can also cause certain side effects that you should be aware of, particularly when starting out. At the beginning of the diet process, your body uses your remaining glucose for energy, resulting in tiredness and lethargy.


Other discomforts include headaches, dizziness, nausea, and cramps. This can be controlled but when starting the ketogenic diet for medical treatment,  it's always best to go through the process with a specialist, who can advise you on the best course of action and explain what is happening, and why. These side effects are usually transient.


People with very rare metabolic problems such as beta oxidation deficiency and those with some forms of Porphyria shouldn't attempt a ketogenic diet.


Individuals with type 1 diabetes might benefit tremendously from avoiding high carbohydrate intake but, they must seek assistance and have very careful monitoring of their blood glucose levels before attempting significant reductions in carbohydrates.


Does the ketogenic diet have side effects?

A ketogenic diet can unmask underlying problems including problems with histamine, deficiencies of certain enzymes and co-factors necessary to release the energy in fats (which become the principal source of energy in a ketogenic diet), reduced digestive function, perceived restrictiveness of such a diet (it is important to appreciate that one can enjoy what they eat while following a ketogenic diet) and problems with the good bacteria in the gut (“gut microbiome”). There might also be genetic influences in how someone metabolises certain nutrients that could also play a role. A specialist who understands these issues should be able to provide the right guidance. 



If you're considering a ketogenic diet for health reasons and would like specialist advice about management or health repercussions, visit Dr Lulsegged's Top Doctors profile today.   

By Dr Abbi Lulsegged
Endocrinology, diabetes & metabolism

Dr Abbi Lulsegged is an experienced consultant physician and endocrinologist, practising in a number of clinics in central London and southern England. Dr Lulsegged has a special interest in unexplained medical conditions, obesity, fatigue, and reversal of type 2 diabetes. He also has an interest in optimising patients for important goals such as pregnancy or surgery, taking into account important environmental factors. He has broad experience in treating all manner of endocrine conditions including polycystic ovarian syndrome, osteoporosis, male and female sex hormone dysfunction, thyroid nodules, adrenal diseases, endocrine causes of high blood pressure, problems with salt, potassium and magnesium levels (electrolyte imbalance) and pituitary disease. 

He is passionate in determining the root cause(s) of why a patient is unwell - whether it is a seemingly straightforward thyroid problem or a more complex, long-standing, baffling conundrum. By taking this approach, he believes that patients are managed much more holistically with the potential to not only positively impact existing conditions but, also invest in future health. He has considerable expertise in coordinating the care of patients with complex, unexplained conditions, working closely with experienced, dedicated colleagues. He sees patients from all over the country and overseas. Dr Lulsegged developed from scratch a successful and thriving endocrine service at Bromley Hospitals, part of King's College Hospital. He is also a notable leader and educator, with experience heading the production of guidelines on management of vitamin D deficiency serving a population of 1 million. He has lectured both nationally and internationally. 

Dr Lulsegged has presented in the Houses of Parliament on the subject of reversal of type 2 diabetes, has been interviewed regularly on radio programs and has been quoted by national press. He appeared on the BBC to discuss treatment of diabetes - the program received very high viewer ratings. He has received clinical excellence awards for his outstanding patient care, and has been appointed as a fellow of the Royal College of Physicians as an acknowledgment of his work in both medicine and his chosen specialty. 


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