Ketogenic diet is specially designed to induce ketosis in the body. When glucose in the body drops to very low levels, the body switches to fat as a source of energy. The body burns the stored fats and converts it into energy. The fat metabolism produces molecules called ketones. These are compounds composed of 2 groups of atoms linked together by a carbonyl functional group. They can be use by the cells as a source of energy. The brain, in particular, can use ketones for about 70 to 75% of its energy requirements.
What Causes Ketosis?
The body enters a ketotic state when there is not enough amount of glucose in the cells. There are not enough carbohydrates to supply the glucose needs of the body. Ketosis is induced in the following conditions:
• Starvation
Starvation and fasting states results in inadequate or no intake of food that the body can digest and convert into glucose. The body normally enters starvation mode during sleep, skipping meals or when fasting. The lack of food intake results in a drop in blood glucose levels. Glycogen (stored glucose) stores are mobilized. They are converted into glucose for the body to use as energy. To augment the glycogen conversion, the body starts to burn the stored fats. Ketogenesis occurs in response to the ketotic state (lack of available glucose). This is the process that metabolizes fats to produce an alternative energy form-ketones.
• Insulin problems
• Low carbohydrate intake
Effects of ketosis in the body
Ketosis causes the release of ketones in the body. These molecules can cause a few symptoms, which can be either negative or positive.
Negative Effects
Most of the negative effects experienced gradually wear off as the body adjusts to the ketones as sources of energy. Most people are able to adjust by the end of the first week after starting on a ketogenic diet. Others may take up to 2 weeks. It may take up to 12 weeks for the body to adapt 100%to fat burning.
The desired effects usually take longer to be achieved. Subtle effects are seen between 6 and 8 weeks.
• Weakness
• Light-headedness
• Fatigue
• Headaches
• Mild irritability
• High cholesterol (if too much unhealthy fats)
• Vomiting
• Ketoacidosis
This effect can only occur when the body’s control mechanism fails. Lack of insulin allows the ketone levels to increase in levels that can already be toxic to the body. This condition is called ketoacidosis. However, ketosis induced by diet is not enough to cause this condition.
In children, ketogenic diets can be used as part of epilepsy management. The following are some of the reported side effects of this diet:
• Constipation
• Dehydration
• Kidney or gall stones
• Slowed or poor growth
• Drowsiness
• Exacerbation of gastro-oesophageal reflux
• Increased bruising
• Increased risk of fractures
• Excess ketosis and acidosis
• Psychosocial food refusal
Women with epilepsy using the ketogenic diet can experience:
• Menstrual irregularities
• Eye problems
• Decreased bone density
• Pancreatitis
Micronutrient deficiencies may result from the restrictions. Most carbohydrate-rich foods are also rich in vitamins and minerals. The severe restrictions on carbohydrate intake may cause deficiencies of these essential nutrients. It is very important to also consider the micronutrient (vitamins and minerals) intake along with the macronutrient (fats, proteins and carbohydrates) counting and proportioning in meals. Supplementation may also be necessary to avoid deficiency states.