What is a Keto Diet?
The main component of the ketogenic diet is healthy fats. It contains an adequate amount of protein. But, there is a lesser amount of carbohydrates.1Fats make up to 65% of total calorie intake in the ketogenic diet.2 Carbohydrates are as low as 5%.3 The carbohydrate intake is 20-60g/day.2
It is a diet that makes the body to use ketone bodies as the main energy source instead of glucose. Ketone bodies’ production is increased, which is called ketosis. The body always stays in a state of ketosis due to the consumption of such a diet.4
In a ketogenic diet, carbohydrates intake is limited. High sugar foods and refined products should be avoided. Only a limited amount of fruit should be taken. Beans, potatoes, and other vegetables are avoided. Processed foods (like salad dressings) and alcohol intake are also limited. Meat, fish, eggs, coconut and avocado oils, herbs, and low carbohydrate vegetables are part of the ketogenic approved diet.3 If a person has a sedentary lifestyle, he should keep his carbohydrates intake in check.5
Pros of Keto Diet
1. Metabolic Syndrome and Diabetes Mellitus
The keto diet has shown to decrease insulin resistance. In keto diet, low carbohydrate intake lowers the glucose concentrations in blood.4 Initial studies suggest that the keto diet may be useful in type 2 diabetes mellitus(a disorder of glucose metabolism).1,6 But, a diabetic patient should consult a doctor before using a keto diet.4 Keto diet may also decrease the progression of diabetic nephropathy.7 Some studies also suggest use in hypercholesterolemia.1 It is also helpful in cases of high blood pressure.4
2. Weight Loss
Keto diet improves many health parameters due to its various metabolic effects. High fat intake increases fat oxidation if glucose is low. Fat loss occurs due to calorie burn mainly. These factors may cause weight loss due to consumption of the keto diet.4
Low carbohydrates(glucose) intake leads to decrease levels of insulin in the blood, and a high intake of carbohydrates causes high insulin levels. Insulin prevents lipolysis(the breakdown of body fat) and promotes lipogenesis( making of body fat). The keto diet keeps low glucose concentration in blood. So, insulin levels are low as well. All these factors cause a decrease in body fat, causing weight loss.3 Keto diet also decreases the craving for foods and promotes satiety thus maintaining recommended calorie intake per day.5
The ketogenic diet can be used to control seizures in children. In the early days, it was considered to be more effective in the control of seizures than anticonvulsant drugs. It is gaining attention to be effective in the management of epilepsy in both children and adults.1 Ketogenic diets have been used to treat epilepsy since the early 1920s.8
This leads to the idea that it may be used to treat more diseases in the future because it has an impact on brain metabolism and function. The ketogenic diet appears to have disease-modifying effects. A person remains seizure-free for some time even after the discontinuation of this diet. The role of the ketogenic diet as antiepileptic is vague, but it may do so by providing neuroprotection.1
4. Neurodegenerative Diseases
Various researches are going on the effect of a keto diet on neurodegenerative diseases. These researches are in initial stages, and there is no definite conclusion. The basic role of the keto diet in the neuroprotection may be the mechanism.1
It is thought to be effective in Parkinson’s disease. Parkinson’s disease occurs due to the disorder of mitochondrial complex (part of the cell involved in cellular metabolism). The keto diet reduces the need for these complex mitochondrial functions because it provides another pathway for cellular metabolism. Clinical studies have shown improvement in Parkinson’s disease patients who use the keto diet. There may be another mechanism for this improvement. Weight loss and low dietary proteins may have improved the levodopa function by altering its pharmacokinetics.1
In research done on the mouse model, the keto diet promises to have beneficial effects in Alzheimer’s disease. It reduced the amount of amyloid protein deposition in the brain, but there was no improvement in brain function. There was reduced neuron loss.1 Researches on human beings are not yet present.
5. Behavior and Cognition
The ketogenic diet has neuroprotective functions. It improves social behavior, cognitive skills, and memory of a person. In one study, the children taking the ketogenic diet were more alert and attentive. It also affects social behavior, so it seems that it also affects the emotional neurological pathways.9
6. Chronic Pain
Patients suffering from untreatable diseases experience chronic pain in which 1/5th of health resources are utilized to relieve it. Ketogenic diets decrease inflammation, which may be useful in the management of chronic pain. Further research needs to be done in this field.10
7. Chronic Kidney Disease
A ketogenic diet containing low protein is beneficial for a patient of chronic kidney disease. It helps to improve the metabolic derangements of chronic kidney disease. Keto diet delays the fall down of renal function. Keto diet should be used in addition to dialysis in the management of chronic kidney disease because it has better outcomes. Nutritional monitoring should be part of management.11
Keto diet may also have a role in cancer patients. It has shown to reduce the size and growth of the brain tumor in one study on the mouse model.1 The mechanism may be that tumor cell consumes glucose much faster than the normal cells and depends on glycolysis(glucose metabolism). It is called a Warburg effect. The keto diet helps to maintain a low glucose concentration in blood. This causes starvation of tumor cells as tumor cells are less able to use ketone bodies as metabolic fuel. This inhibits tumor growth.2,4
Keto diet also increases the efficacy of chemotherapy and radiotherapy by cell-specific oxidative stress. It also helps to maintain lean body mass by preserving protein in cancer patients. In animal studies, it has also shown to reduce the metastasis( spread of the tumor to distant sites).2
In addition to anticonvulsant effects, the keto diet may also have a beneficial effect on migraine headaches.1 They reduce the inflammation that is the basis of pain in migraine.12
10. Sleep Disorders
The Atkins diet is similar to the keto diet, as both are having low carbohydrates. In the Atkins diet, the amount of carbohydrates is gradually increased. But in the keto diet, the amount of carbohydrates is always kept low. The use of the Atkins diet in a small case study has shown improvement in patients having sleep disorders like narcolepsy.1 The keto diet improves the pattern and quality of sleep but, the mechanism is unclear.9
11. Psychiatric Disorders
Researches also suggest the use of a keto diet in different psychiatric conditions, but the mechanism of action is not known. It can be used in cases of autism and depression.1
12. Gynecological Issues
Keto diet may have a role in metabolic syndrome. It may also be useful in case of the polycystic ovarian syndrome(PCOS)1,13 Ketogenic diet has shown to improve fertility. These effects of the ketogenic diet are independent of weight loss and less calorie intake.14
13. Skin Disorders
Keto diet helps to improve some skin conditions like acne. High sugar and carbohydrate diets make acne more severe. So, a keto diet may be helpful in such conditions. It also has a role in psoriasis (plaque skin disorder). In a case study of psoriasis, the introduction of ketogenic diet along with medications was helpful to improve the condition and reduce its severity.3
Cons of Keto Diet
The adverse effects don’t occur commonly. But, a person needs to know and recognize them if he is taking a ketogenic diet.1 They are divided into early-onset and late-onset effects.
Early-onset effects include gastrointestinal disturbances, hypoglycemia (less glucose in the blood), acidosis and dehydration, weakness, and malaise. These symptoms may occur when a person initiates a ketogenic diet and resolves with time if the person doesn’t fast.1 Keto diet also results in a fruity smell in breath and urine.3
Late-onset effects. They occur when a person uses a ketogenic diet for the long term. It includes kidney stones and dyslipidemia (lipid profile of a person is affected). It also decreases the growth rate of children.1
1. Keto Flu
When a person starts to consume a keto diet, he may experience unfavorable side effects like headache, nausea, malaise, hunger, dehydration, body aches, and irritability, etc. in the initial phase due to diet transition and low carbohydrates intake. This is known as Keto flu. It may last for some days, but the condition improves afterward.1,4
The person may also experience constipation. He should drink a lot of water and eat adequate dietary fiber in addition to ketogenic diet.3
The person may feel sluggish for a few days in the initial stages of starting the keto diet. The reason is that glucose is the main source of energy for the brain. When carbohydrate intake is low, glucose level will low as well. Cognitive functions of a person may be affected until the brain adapts itself to the new diet and use ketone bodies as an energy source.5
2. Nutrient Deficiencies
The keto diet is not balanced. As specific food products are absent from the diet, it may lead to various nutrient deficiencies. It can be prevented by using guidelines directed by a dietician. There must be an intake of a wide variety of food in addition to a high amount of fats. You should consume enough fruits, legumes, and meat that nutrient deficiency doesn’t occur. The less intake of these foods may cause vitamins and some other mineral (iron, magnesium, etc.) deficiencies. There should be adequate dietary fiber intake as well.4
3. Endurance Competition
A low carbohydrate diet is associated with incompetent training adaptations as compared to a high carbohydrate diet.5 It decreases energy and endurance in athletes.15 A low carbohydrate diet (ketogenic diet) decreases power training, outcome, and performance in athletes. Athletes are advised to avoid the keto diet if they want to perform at high levels.5,16
4. Gut Health
The keto diet doesn’t contain enough dietary fiber. Less dietary fiber is not good for gut health and may cause conditions like constipation. One must make sure that he is taking enough dietary fiber by consulting a dietician.4
5. Skin Conditions
The ketogenic diet may have a bad effect on the skin as well. There was a case in which a strict ketogenic diet caused an itchy skin condition known as prurigo pigmentosa. But, these skin conditions are rare.3
6. Eating habits
When one micromanages his dietary intake and takes account of everything he eats irrespective of the body’s needs, it can cause psychological distress “such as shame, and binge eating. Restriction can lead to bingeing, which often leads to guilt, which then leads back to restriction in a continuous cycle”.17
When a person consumes a ketogenic diet (high in fats), it adversely affects the lipid profile of that person. In one study, children consuming keto diet have high levels of LDL and VLDL (bad cholesterol) and low levels of HDL (good cholesterol). Discontinuation of the keto diet returns the lipids towards the baseline. A person should use the ketogenic diet for a maximum of 2 years. Then he should return to diet with a normal amount of fats.1
Some researchers have shown that the idea that a keto diet makes a person dyslipidemia is false.1 A study done in 2004 showed that the use of the ketogenic diet was associated with low LDL and glucose.8 More research needs to be done to find the definite effect of a keto diet on dyslipidemia.
8. Heart Health
In a ketogenic diet, a person eats a high amount of fat and meat. Their use is usually prohibited in patients having cardiovascular problems. The keto diet may have saturated fat content that can lead to high LDL, and it can contribute to the development of heart problems.13,18. On the other hand, the diets containing plant foods have shown a decreased risk of cardiovascular problems, and these diets increase the life span of a person.18
9. Kidney Stones
Keto diet causes acidosis and acidifies the urine. It also leads to an increase in calcium excretion. This also contributes to the formation of kidney stones. Almost 5% of children taking a keto diet develop kidney stones. One should use prophylactic oral potassium citrate to prevent kidney stones1,19
10. Growth Rate of Children
Keto diet is not a balanced diet. It decreases the growth rate of children. Discontinuation of keto diet results in rapid growth. The children on the keto diet should be monitored regularly.1
11. Skeletal Fractures
Keto diet also decreases bone density. It increases the risk of skeletal fractures. The role of calcium supplementation is not proven.1
The use of the keto diet and less restrictive Atkins diet may have beneficial effects ranging from use in neurological disorders to gynecological disorders. One has to adhere to the diet to have these good effects. But it may also have adverse effects. A person on a keto diet should always be supervised and monitored by a team. The team should consist of a dietician and a physician.
- Freeman, J. M., Kossoff, E. H. & Hartman, A. L. The ketogenic diet: One decade later. Pediatrics vol. 119 535–543 (2007).
- Suzanna Maria Zick, N. M. D. S. M. D. I. A. M. Pros and Cons of Dietary Strategies Popular Among Cancer Patients. (2018).
- The Ketogenic Diet and Skin | Dermveda.
- The Pros and Cons of the Keto Diet | HealthConnect.
- The Pros and Cons of The Ketogenic Diet | Cellucor.
- Farrés, J. et al. Revealing the molecular relationship between type 2 diabetes and the metabolic changes induced by a very-low-carbohydrate low-fat ketogenic diet. Nutr. Metab. 7, 88 (2010).
- Liu, D. et al. Low-protein diet supplemented with ketoacids delays the progression of diabetic nephropathy by inhibiting oxidative stress in the KKAy mice model. Br. J. Nutr. 119, 22–29 (2018).
- Ketogenic vs. Paleo Diet: What’s the Difference.
- Hallböök, T., Ji, S., Maudsley, S. & Martin, B. The effects of the ketogenic diet on behavior and cognition. Epilepsy Res. 100, 304–309 (2012).
- Masino, S. A. & Ruskin, D. N. Ketogenic diets and pain. in Journal of Child Neurology vol. 28 993–1001 (NIH Public Access, 2013).
- Garneata, L. & Mircescu, G. Effect of Low-Protein Diet Supplemented With Keto Acids on Progression of Chronic Kidney Disease. Journal of Renal Nutrition vol. 23 210–213 (2013).
- Less carbs, more fat: ketogenic diet makes migraine patients’ headaches disappear | HuffPost.
- The Pros And Cons Of The Keto Diet, According To Doctors And Nutritionists | HuffPost Life.
- Kulak, D. & Polotsky, A. J. Should the ketogenic diet be considered for enhancing fertility? Maturitas vol. 74 10–13 (2013).
- The Pros and Cons of a Keto Diet – Crisp Regional Hospital.
- Zinn, C., Wood, M., Williden, M., Chatterton, S. & Maunder, E. Ketogenic diet benefits body composition and well-being but not performance in a pilot case study of New Zealand endurance athletes. J. Int. Soc. Sports Nutr. 14, 22 (2017).
- Pros and Cons of the Ketogenic Diet | Northwestern Medicine.
- O’Neill, B. & Raggi, P. The ketogenic diet: Pros and cons. Atherosclerosis vol. 292 119–126 (2020).
- Choi, J. N. et al. Renal stone associated with the ketogenic diet in a 5-year old girl with intractable epilepsy. Yonsei Med. J. 51, 457–459 (2010).
Dr Martin receives his MD from University of Iowa. His expertise includes microbiology, anatomy and clinical psychology. He also dedicates himself to continuous learning in different fields.