Ketogenic Diet Pros And Cons

We currently live in a world of diet culture, whereby people tend to believe that to be perceived as healthy and beautiful, we have to be thin. One of the ways that people all over the world lose weight is by following all sorts of diets. Hundreds of diets share the same idea of limiting the quantity and type of nutrient(s) and/or foods you consume. Without a doubt, it is important to watch what you eat and reinforce healthy eating habits, but deliberately limiting the intake of essential nutrients and vitamins through diets could be detrimental to your health. 

Furthermore, inappropriate choice of a diet plan due to an inadequate understanding of how different diets induce weight loss could aggravate existing medical conditions or lead to adverse side effects, eventually doing more harm than good. Therefore, it is vital to know more about a specific diet, its benefits and drawbacks, to make informed decisions. 

In this article, we will dive deeply into the most famous of all diets, the one that has taken social media by storm - the ketogenic diet. We will then discuss the ketogenic diet's pros and cons, which will help you decide whether it is a diet for you. 

About the ketogenic diet

So what is a ketogenic diet? The ketogenic diet, also called the keto diet, primarily consists of rigorously limiting the intake of carbohydrates (5-10% of total daily calories) while allowing high fat (saturated and unsaturated; 55-60%) and moderate protein (30-35%) intake.14,16,18 The keto diet is an umbrella term for low-carb, high-fat diets, including standard ketogenic, very low-carb, and well-formulated ketogenic, among others.12 These diets share the same principle and only differ in the ratio of macronutrient consumption, with some limiting carbohydrate intake to as little as 20 grams a day. For reference, according to Mayo Clinic, an average adult getting 2000 calories per day should consume 225-325 grams of carbohydrates which ultimately make up 45-65% of the total daily calories.

Carbohydrates are an essential part of our daily diet as they provide our body with glucose, which is used by our body as a primary energy source that supports our everyday functioning. The idea behind the keto diet is to consume as little carbohydrates as possible to starve our body of glucose and deliberately induce a state of ketosis, whereby the body is triggered into a fasting-like mode as it does not have enough glucose to sustain its functioning. So to keep functioning, our liver starts to break down stored fats into ketones, which are then used as an alternative energy source. As a result of ketosis, our body burns fat for energy, and we experience weight loss.14,16,18  

Pros and cons

Despite everything sounding relatively straightforward, let's look at specific pros and cons of a ketogenic diet that you should consider before committing yourself to this particular diet. 


  1. Rapid weight loss

The keto diet is recognised as a diet that induces fast weight loss, which includes water loss followed by fat loss. According to a systematic review of 11 randomised control trial studies, people in the ketogenic diet group lost 2.2 kilograms more than people in the low-fat diet group. However, other systematic reviews show no long-term difference in diets. Therefore, there is a need for more clinical studies assessing the utility of the ketogenic diet in short and long-term weight loss when compared to other diets.12,14,17,19

  1. No calorie restriction

The original ketogenic diet has no calorie restriction or food weighing. Therefore, it may appeal to people who are uncomfortable with limiting their caloric intake or the amount of food they consume. However, over the years, new variations of the keto diet have emerged, and they may involve calorie restrictions. These types of diets are incredibly restrictive and should be considered with caution.12

  1. Appetite control

The ketogenic diet has been implicated in suppressing appetite, which is thought to facilitate weight loss. Most studies show that keto diets suppress the secretion of the ghrelin hormone, which regulates feelings of hunger. However, the molecular mechanisms of appetite control in keto diets seem to be much more complicated than initially thought, requiring more studies investigating this issue.10,21

  1. Reduce insulin levels and manage blood glucose levels

Studies show that decreasing carbohydrate consumption can significantly lower one's blood glucose and insulin levels. Under normal conditions, carbohydrates are turned into glucose upon consumption, leading to spikes in blood glucose levels. These spikes send signals to the pancreas to produce the hormone insulin , which controls blood glucose  levels. Limiting carbs could help manage these spikes and consequently reduce the need for insulin production.1,4,16

  1. Decrease inflammation

Numerous studies have shown the antioxidant and anti-inflammatory effects of keto diets. The diet involves consuming increased quantities of anti-inflammatory foods, such as eggs, avocado, spinach, and broccoli and decreased amounts of inflammatory foods, such as sugar, starch, and processed foods. Following a keto diet leads to a prolonged state of ketosis, during which our body inhibits inflammatory pathways.11,16

  1. Acne management 

The ketogenic diet results in little insulin secretion, which has been previously recognised as a notable driver of acne. Therefore, by reducing insulin levels, the keto diet helps ameliorate acne.4

  1. Application in cancer treatment 

Studies suggest that keto diets create a very unfavourable metabolic environment for cancer cells, therefore, having a potential application in cancer therapies. Recent preclinical and clinical studies show the possible use of keto diets along with standard cancer therapies, as they enhance the starvation of cancer cells, making them more vulnerable to chemotherapy and radiation. However, more controlled clinical trials are needed to establish this link.6

  1. Prevention of dementia

Recent studies have shown the potential implications of keto diets in treating and preventing dementia. Several human trials examining the utility of keto diets in older adults have reported improvement in cognitive function and prevention of the progression of neurocognitive impairment.2,3,7,11,22,25

  1. Seizure management 

Keto diets have initially been reserved for the treatment of patients with seizures which cannot be controlled with anti-epileptic drugs. The diet is used for different types of seizures and patients of different ages. However, it is mainly prescribed for children and not adults due to the cardiovascular risks associated with increased fat intake. There is a lot of literature supporting the use of keto diets in seizure control of people with pharmacoresistant epilepsy, but the molecular mechanisms behind this function are still to be elucidated.8,15


  1. Nutrient deficiency

Following the keto diet requires people to give up essential nutrients, which could result in nutrient deficiencies. The keto diet restricts the consumption of whole grains, starchy vegetables, fruits and other micronutrient-rich products. Therefore, if you are following a keto diet, you may experience decreased magnesium, selenium, iodine, vitamins A, E, and other micronutrients.8,23

  1. Liver problems

Keto diets rely heavily on the consumption of fats. Over time, this can lead to increased fat storage in the liver, increasing one's risk of nonalcoholic fatty liver disease and insulin resistance.9,26

  1. Hypoglycemia

Hypoglycemia is a condition whereby one's blood sugar levels are abnormally low (below 3.9 mmol/L). As a result of keto diets, people's blood sugar levels drop, which is usually a good sign. However, people with low blood sugar levels can develop symptoms of hypoglycemia due to blood glucose levels falling too low. The symptoms include dizziness, difficulty concentrating, and trembling, among others.26

  1. Constipation

Constipation is one of the common short-term side effects of all ketogenic diets. It arises due to limited fibre intake, which is needed for healthy gut and bowel movements. In addition, starting a keto diet causes increased urination and sodium loss, leading to dehydration, which also is implicated in constipation.5

  1. Rise in “bad” cholesterol in the blood

Some studies suggest that increased fat consumption when following a keto diet can negatively affect the body, withemphasis on the Low-density lipoprotein (LDL) cholesterol also known as 'bad' cholesterol. High levels of LDL increase your risk of developing cardiovascular disorders.14,26

Side effects of ketogenic diet

The followers of the ketogenic diet report a number of short-term (up to 2 years) side effects: 

  • Insomnia 
  • Nausea/vomiting 
  • Constipation 
  • Headache 
  • Fatigue 
  • Dizziness

Most of these side effects are experienced in the first weeks of following the keto diet. There is even a concept of keto-flu when people report almost flu-like symptoms of dizziness, headache, fatigue and muscle cramps shortly after starting the diet. However, these symptoms usually resolve over days or weeks and can be improved by ensuring adequate fluid and electrolyte intake.  

The long-term side effects are less known due to limited literature investigating this issue. However, some reports report side effects like kidney stones, nutrient and vitamin deficiencies, and fatty liver disease. 


What do you eat while on a keto diet

The diet has an increased fat consumption requirement, and the followers must eat saturated and unsaturated fat during each meal. The foods that you should eat include:

  • Nuts
  • Seeds
  • Avocados 
  • Olive oil
  • Butter
  • Meat
  • Poultry
  • Fish
  • Eggs
  • Cheese
  • Leafy greens 
  • Non-starchy vegetables
  • Fruits/berries (low in sugar and small portion size) 

What should I not eat on a keto diet

The keto diet significantly limits your carb intake, with people eating as little as 20 grams of carbohydrates per day. Therefore, you should limit the consumption of foods with high carbohydrate content. Furthermore, you should limit your sugar and starch intake. The foods to avoid include: 

  • Bananas
  • Mangoes
  • Candy
  • Biscuits 
  • Cakes
  • Yoghurts
  • Cereal 
  • Porridge 
  • Oatmeal 
  • Sauces 
  • Natural sweeteners
  • Pasta
  • Rice
  • Potatoes 

Who should avoid keto diet

Due to the potential side effects of the keto diet, some people are not advised to follow this particular diet. These include:  

  • People with diabetes taking insulin, metformin 
  • Underweight people 
  • People with a history of or are suffering from an eating disorder
  • Pregnant women 
  • Children under the age of 18 

If you fall under any of the specified categories, please consult your health provider on the suitability of the ketogenic diet in your particular case. 

How long should I do the keto diet for?

The keto diet should be followed for a minimum of 2-3 weeks up to 6-12 months. It is essential to monitor your health and well-being and report any side effects you might experience while following the diet. If you have any concerns or medical history of the conditions that you think might be aggravated by the ketogenic diet, please seek advice from your health provider before you start the diet plan. 


The ketogenic diet is one of the famous weight-loss diets, which involves rigorously limiting your carbohydrate intake and compensating with increased fat intake. The diet is fancied by many due to its potential to induce fast weight loss without necessarily limiting one's caloric intake. Keto diets have numerous benefits and have been implicated in cancer treatment, prevention of seizures, and maintenance of brain health, among others. However, ketogenic diets also have multiple risks, including nutritional deficiency, liver problems, constipation and keto-flu symptoms. Furthermore, due to the severity of the side effects, some people should refrain from following keto diets or discuss its implementation with their healthcare provider first.


  1. Yuan X, Wang J, Yang S, Gao M, Cao L, Li X, et al. Effect of the ketogenic diet on glycemic control, insulin resistance, and lipid metabolism in patients with T2DM: a systematic review and meta-analysis. Nutr Diabetes. 2020 Dec;10(1):38.
  2. Włodarek D. Role of Ketogenic Diets in Neurodegenerative Diseases (Alzheimer’s Disease and Parkinson’s Disease). Nutrients. 2019 Jan 15;11(1):169.
  3. Witte AV, Fobker M, Gellner R, Knecht S, Flöel A. Caloric restriction improves memory in elderly humans. Proc Natl Acad Sci USA. 2009 Jan 27;106(4):1255–60.
  4. Skow SL, Jha RK. A Ketogenic Diet is Effective in Improving Insulin Sensitivity in Individuals with Type 2 Diabetes. CDR [Internet]. 2022 Apr 25 [cited 2022 Nov 20];18. Available from:
  5. Sanjoaquin MA, Appleby PN, Spencer EA, Key TJ. Nutrition and lifestyle in relation to bowel movement frequency: a cross-sectional study of 20 630 men and women in EPIC–Oxford. Public Health Nutr. 2004 Feb;7(1):77–83.
  6. Weber DD, Aminzadeh-Gohari S, Tulipan J, Catalano L, Feichtinger RG, Kofler B. Ketogenic diet in the treatment of cancer – Where do we stand? Molecular Metabolism. 2020 Mar;33:102–21.
  7. Rusek M, Pluta R, Ułamek-Kozioł M, Czuczwar SJ. Ketogenic Diet in Alzheimer’s Disease. IJMS. 2019 Aug 9;20(16):3892.
  8. Ruiz Herrero J, Cañedo Villarroya E, García Peñas JJ, García Alcolea B, Gómez Fernández B, Puerta Macfarland LA, et al. Safety and Effectiveness of the Prolonged Treatment of Children with a Ketogenic Diet. Nutrients. 2020 Jan 24;12(2):306.
  9. Rosqvist F, Kullberg J, Ståhlman M, Cedernaes J, Heurling K, Johansson HE, et al. Overeating Saturated Fat Promotes Fatty Liver and Ceramides Compared With Polyunsaturated Fat: A Randomized Trial. The Journal of Clinical Endocrinology & Metabolism. 2019 Dec 1;104(12):6207–19.
  10. Roekenes J, Martins C. Ketogenic diets and appetite regulation. Current Opinion in Clinical Nutrition & Metabolic Care. 2021 Jul;24(4):359–63.
  11. Pinto A, Bonucci A, Maggi E, Corsi M, Businaro R. Anti-Oxidant and Anti-Inflammatory Activity of Ketogenic Diet: New Perspectives for Neuroprotection in Alzheimer’s Disease. Antioxidants. 2018 Apr 28;7(5):63.
  12. Paoli A, Rubini A, Volek JS, Grimaldi KA. Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. Eur J Clin Nutr. 2013 Aug;67(8):789–96.
  13. Ota M, Matsuo J, Ishida I, Hattori K, Teraishi T, Tonouchi H, et al. Effect of a ketogenic meal on cognitive function in elderly adults: potential for cognitive enhancement. Psychopharmacology. 2016 Oct;233(21–22):3797–802.
  14. O’Neill B, Raggi P. The ketogenic diet: Pros and cons. Atherosclerosis. 2020 Jan;292:119–26.
  15. Neves GS, Lunardi MS, Lin K, Rieger DK, Ribeiro LC, Moreira JD. Ketogenic diet, seizure control, and cardiometabolic risk in adult patients with pharmacoresistant epilepsy: a review. Nutrition Reviews. 2021 Jul 7;79(8):931–44.
  16. Mongioì LM, Cimino L, Greco E, Cannarella R, Condorelli RA, La Vignera S, et al. Very-low-calorie ketogenic diet: An alternative to a pharmacological approach to improve glycometabolic and gonadal profile in men with obesity. Current Opinion in Pharmacology. 2021 Oct;60:72–82.
  17. Mohorko N, Černelič-Bizjak M, Poklar-Vatovec T, Grom G, Kenig S, Petelin A, et al. Weight loss, improved physical performance, cognitive function, eating behavior, and metabolic profile in a 12-week ketogenic diet in obese adults. Nutrition Research. 2019 Feb;62:64–77.
  18. Masood W, Annamaraju P, Uppaluri KR. Ketogenic Diet. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 [cited 2022 Nov 16]. Available from:
  19. Mansoor N, Vinknes KJ, Veierød MB, Retterstøl K. Effects of low-carbohydrate diets v . low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials. Br J Nutr. 2016 Feb 14;115(3):466–79.
  20. Dowis K, Banga S. The Potential Health Benefits of the Ketogenic Diet: A Narrative Review. Nutrients. 2021 May 13;13(5):1654.
  21. Deemer SE, Plaisance EP, Martins C. Impact of ketosis on appetite regulation—a review. Nutrition Research. 2020 May;77:1–11.
  22. Davis JJ, Fournakis N, Ellison J. Ketogenic Diet for the Treatment and Prevention of Dementia: A Review. J Geriatr Psychiatry Neurol. 2021 Jan;34(1):3–10.
  23. Christodoulides SS, Neal EG, Fitzsimmons G, Chaffe HM, Jeanes YM, Aitkenhead H, et al. The effect of the classical and medium chain triglyceride ketogenic diet on vitamin and mineral levels: Vitamin and mineral levels on ketogenic diet. Journal of Human Nutrition and Dietetics. 2012 Feb;25(1):16–26.
  24. Bueno NB, de Melo ISV, de Oliveira SL, da Rocha Ataide T. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. Br J Nutr. 2013 Oct 14;110(7):1178–87.
  25. Broom GM, Shaw IC, Rucklidge JJ. The ketogenic diet as a potential treatment and prevention strategy for Alzheimer’s disease. Nutrition. 2019 Apr;60:118–21.
  26. Anekwe C, Chandrasekaran P, Stanford FC. Ketogenic Diet-induced Elevated Cholesterol, Elevated Liver Enzymes and Potential Non-alcoholic Fatty Liver Disease. Cureus [Internet]. 2020 Jan 8 [cited 2022 Nov 20]; Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Anna Mazepa

Masters of Science - MSc Clinical Neuroscience/ University College London

Anna is a master’s graduate with interest in psychology and neuroscience. Since starting her undergraduate psychology degree, she has been passionate about scientific writing. Anna has been involved in the execution of multiple research projects during her academic journey and has written numerous scientific essays. She continues to be engaged in scientific and medical writing as she works towards becoming a Clinical Psychologist.

Leave a Reply

Your email address will not be published. Required fields are marked * presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818