The ketogenic diet was developed in the 1920s to treat epilepsy. Physicians had long noted that there were fewer seizures when their patients fasted, so to mimic the fasting state, a diet high in fat and very low in carbohydrates was created. When carbohydrates are restricted, the body runs out of glucose quickly and must use a different nutrient source for energy. In periods of starvation or intense exercise, this alternate fuel source is ketones, which are compounds made in the liver from fatty acids.

True ketogenic diets, which provide up to 90% of calories from fat, are still used to treat epilepsy, other neurological conditions and cancer. Those who follow a ketogenic diet for better athletic performance or longevity tout the benefits for its effects on cardiac and metabolic markers.

But as with most issues related to human health, the evidence is mixed. Below we examine the pros and cons of a ketogenic diet. First, the good news…

A ketogenic diet can suppress appetite. Studies evidence a small but significant decrease in appetite which can lead to overall reduction in caloric intake. It is not known if the appetite suppressant effect results from a higher satiety effect of protein in the diet, or from the ketones themselves.

A ketogenic diet lowers triglycerides and raises HDL. Triglycerides are a main component of body fat, and when released into the blood at high levels, they increase the risk of stroke. Triglycerides are often high when a person overconsumes processed food that is high in sugar and fat. HDL or high density lipoprotein is the so-called “good” cholesterol, because levels over 50 mg/dL are protective against heart disease.

A ketogenic diet lowers circulating glucose. As with any diet that removes sugar and refined carbohydrates, glucose levels will drop. Reduced glucose leads to lower insulin and therefore less chance of developing diabetes.

Now the bad news.

A ketogenic diet is restrictive and difficult to adhere to. Low fat, low carb and high protein diets all lead to short-term weight loss, but can be hard to maintain. One study attempting to compare weight loss maintenance after one year did not have any data for the ketogenic group because none of the participants were still following the diet a year later.

A ketogenic diet can cause digestive problems. The diet tends to be constipating and dieters often use laxatives to stimulate bowel movements. While it is possible to obtain the recommended 30 grams of fiber per day from the non-starchy vegetables allowed on the diet, those who prefer salami and cheese to a serving of asparagus may end up deficient. Additionally, bloating and/or constipation may result from consuming dairy products, which many adults are unable to digest.

You lose weight, but not fat. As with any dietary intervention that causes weight loss, lean muscle tissue will decrease unless strength training is employed concurrently. Body builders who follow a ketogenic diet often eat extra carbohydrates one day a week. The insulin needed to metabolize carbohydrates is an anabolic hormone that stimulates muscle growth and improves body composition.

As no one diet suits everyone, consult a practitioner with nutrition training to determine which eating program is right for you.

Dr. Needle is a naturopathic doctor at Optimal Health Center in Palm Desert and can be reached at (760) 568.2598.