Carbohydrates are the primary fuel of the human body. A few days without carbs drives the body into a metabolic state known as ketosis, where the primary energy source is fat. A diet that induces a permanent state of ketosis is known as a ketogenic diet. This dietary regimen is currently gaining popularity, largely fueled by the weight loss bandwagon and the publicity created by American physician Dr. Atkins for his Atkins diet. While a ketogenic diet is commonly employed to successfully treat some ailments—even epilepsy in children—its safety over the long term has remained an under-researched and controversial topic.

What are the consequences of a persistently altered metabolism?

ketogenic-dietA 2010 study carried out at Johns Hopkins Medical Institutions found no evidence of significant side effects after a long-term high-fat dietary regimen among epileptic patients. Scientists tracked 101 young patients at the Johns Hopkins Children's Center that underwent a ketogenic regime to treat epileptic seizures. Depending on the patient, the diet lasted between 16 months to 8 years. Researchers did not find any significant side effects caused by the diet, although they noted that potential side effects might take decades to be noticeable and the average body size of the participants was below the norm. As expected, the patients' epileptic episodes were drastically reduced. This was one of the first studies about the long-term effects of a high-fat and low-carbohydrate diet.

What are the disadvantages and possible side effects?

The nutritional profile of a ketogenic diet may potentially cause a number of side effects that range in severity. For example, there is a risk of constipation because dietary fiber is typically present in high-carb foods. Other symptoms include higher cholesterol, kidney stones, low blood sugar, increased blood acidity, and even impaired growth. Ideally, there should be a balance between the macro nutrients. This can be more difficult to achieve with a high-fat diet given that the human body is adapted for a carb-burning mode by default. Greater attention should be given to essential minerals and vitamins as the body will still need these micronutrients to function properly. Nutritional supplements are often necessary.

So is it worth trying?

Some nutritionists claim a ketogenic diet has to be strictly controlled in order to minimize the risks of ineffectiveness, malnutrition and even potentially fatal side effects. One of the greatest dangers associated with this diet is the possibility of inadvertently inducing ketoacidosis. This is an extremely dangerous metabolic state that can lead to death if not promptly halted.

Also, slow deamination of muscle tissue to fuel the body can be a problem, a condition when the body starts to consume itself. People with a poor ability to metabolize fat are at particularly higher risk. And since weight loss is a common effect, this diet might not be appropriate for those on the lower end of the healthy BMI range either.