Obesity has become a serious problem in both developing and developed countries. This condition is associated with a variety of chronic diseases in our health for examples diabetes, high blood pressure, cholesterol etc. According to the research studies, female obesity prevalence for Sri Lanka was 7.3% while male obesity was 2.9% in 2016. Bad feeding habits and unhealthy living style are the major reasons for this problem. People follow different weight reducing methods using reduced calorie and fat intake combined with exercise. However, it will take a long time to obtain better results. Therefore, presently Ketogenic diet has become increasingly popular in our society in order to get effective and efficient reduction in the body weight. 

What is this Ketogenic diet? 
Ketogenic diet is a regimen that constitutes a high-fat diet rich in polyunsaturated fatty acids which is quite effective in reducing body weight, medium-protein, and low-carbohydrates. While in this diet, the fat to carbohydrate ratio is 5:1. 

Ketosis 
Ketosis occurs as a result of the change in the body’s fuel from carbohydrate to fat. When glucose reserves such as glycogen stored in liver and skeletal muscle become insufficient to provide energy needs for human body, production of ketone bodies are occurred by the liver, in order to produce an alternative energy source notably by the central nervous system. Incomplete oxidation of fatty acids by the liver results in the accumulation of ketone bodies in the body. A ketogenic diet maintains the body in a state of ketosis, which is characterised by an elevation of D-b-hydroxybutyrate and acetoacetate. Mild ketosis is a natural phenomenon that occurs in our body during fasting and lactation. In addition, ketosis has a significant influence on suppressing hunger. Hence, a ketogenic diet is a good regulator of the body’s calorie intake and mimics the effect of starvation in the body. 
In the human body, ketone bodies are the substitutes for glucose which provides energy for the brain. The generation of ketone bodies by liver during fasting is essential to provide an alternate fuel to glucose. This is necessary to spare the destruction of muscle from glucose synthesis. 

Different types of Ketogenic diet 
1. Classic Ketogenic Diet (KD) 
There is a fixed ratio of fat to combined protein and carbohydrate by weight and it achieves by excluding high-carbohydrate foods while increasing the consumption of foods high in fat. 
2.Medium-Chain Triglyceride Ketogenic Diet (MCT) 
As less overall fat is required in this diet, a greater proportion of carbohydrate and protein can be consumed by allowing a slightly greater variety of food choices. Normally, most of dietary fat is made of long-chain triglycerides. 

3. Modified Atkins Diet (MAD) 
This diet allows 10- 20g/day of carbohydrate intake and strongly encourages fat intake while there is no calorie restriction. 

4. Low Glycemic Index Treatment (LGIT) 
This diet allows a low-carbohydrate diet by limiting carbohydrate intake to 40-60g/day and foods with low glycemic index (< 50). 

Benefits of Ketogenic diet 
Besides efficient effect of ketogenic diet on weight loss, research studies have discovered that low-carbohydrate ketogenic diets also reduce serum triglycerides dramatically and also reduction in total cholesterol and increase in high-density lipoprotein cholesterol have also been evident. Moreover, low-carbohydrate ketogenic diets have been shown to have immense benefits in blood sugar control. Furthermore, there are some reported beneficial effects on cancer and neurological disorders such as Alzheimer’s disease and epilepsy. 

Adverse effects of Ketogenic Diet 
There are few side effects that come across when people follow ketogenic diet and frequently the most common issues are dehydration or lack of micronutrients (vitamins) in the body since ketogenic diet is limited to carbohydrates. Decreasing the amount of carbohydrates consumed leads depletion of glycogen stores in the liver. Water is stored alongside glycogen for example, 03 grams of water are stored in every gram of deposited glycogen. Therefore, when glycogen stores are depleted, the body loses water. 

1. Cramps Especially leg cramps are pretty common at the beginning of a ketogenic diet. It’s usually occurring in the morning or at night due to lack of minerals, specifically magnesium, in the body. Because, in ketogenic diet, people are not paying attention to fruits which are good source of micronutrients such as vitamins and minerals. 

2. Constipation 
The most common cause of constipation on low carbohydrate is dehydration and lack of fibrous food consumption. Normally, getting of vegetables and fruits are limited in ketogenic diet since most of them are starchy and this will be the cause for occurrence of constipation in people who follow ketogenic diet. 

3. Heart palpitations 
When transitioning to keto, our heart is beating faster and harder. This can happen during the first few weeks of ketogenic diet. A reduction in the amount of fluid in the blood stream leads pumping of blood by heart slightly harder and faster in order to maintain blood pressure. Therefore, this problem can be recovered by drinking plenty of water, juices and eating enough salt. 

4. Bad breath 
Some people can experience characteristic smell from their breath on strict low carbohydrate diet. Because, the smell is from acetone which is a ketone body produced due to our body is burning lots of fat and even converting lots of fat to ketones in order to generate energy for our brain. This smell can surface as a body odour through excessive sweating. However, with the time our body adapts and terminates the leaking of ketones through breath and sweat. 

5. Reduced Physical Performance 
Normally, our body uses energy which is generated by breaking down of carbohydrates. The body has built up an arsenal of enzymes ready for this process and only has a few enzymes to deal with fats mostly to store them. However, when our body has suddenly dealt with the lack of glucose and increase in fats, which means building up a new supply of enzymes, our body becomes induced into a ketogenic state. Then our body will naturally use what’s left of your glucose. Eventually, our body will be depleted of glycogen in muscles which can cause a lack of energy and general lethargy which leads to the reduction of physical performance. 

6. Nutrient deficiencies 
Major concern of keto diet is losing of essential micronutrients. Consuming of fat and proteins based on animal sources will lose essential micronutrients which are highly found in starchy grains, legumes, fruits and vegetables. Moreover, low carbohydrate diet contains only little fiber percentage. 

7. Keto flu 
Keto flu is caused by transition of burning sugar to burning fat in order to meet out body’s energy need. When we switch our dietary plan from high carbohydrate diet to very low carbohydrate diet, it lowers the insulin level in our body. When insulin level is very low, our liver begins conversion of fat into ketones, which is substitutes for glucose. Moreover, when insulin level is dropped, our body responds by excreting more sodium in the urine, along with water. Losing lots of water and sodium is responsible for many of the symptoms of Keto flu such as fatigue, headache, irritability, lack of motivation, dizziness and vomiting. 

8. Keto Rash 
Keto rash is a prurigo pigmentosa, rare inflammatory skin condition happen more frequently in people with increased ketone levels like those with diabetes or people on a keto diet. 

9. Ketoacidosis 
Ketoacidosis is a condition seen in type one diabetics. The main factor for development of ketoacidosis is lack of insulin. The cell cannot shuttle in glucose from the bloodstream for energy use and the body has no signal to stop releasing fats which are converted into ketones. When ketone level gets too high, the blood becomes too acidic and which may potentially become life- threatening. Alcoholism, overactive thyroid and infections such as pneumonia are other medical problems which are associated with ketoacidosis. 

In conclusion, Ketogenic diet is a more beneficial and associated with some improvements in some cardiovascular risk factors, such as obesity, type 02 diabetes and HDL cholesterol levels. However, there are adverse effects which can be classified as mild, moderate and severe short term and long term effects. Therefore, if you need to reduce your body weight through a dietary plan, getting advices from a dietitian or other person who has better knowledge on human nutrition and dieting, is a better option to stay away from these kind of health problems. 

The writer is a medical laboratory technologist at a private hospital and holds a MSc. Degree in Industrial and Environmental Chemistry from the University of Kelaniya and BSc. Food Production and Technology Management degree from the Wayamba University of Sri Lanka.