The ketogenic, or “keto,” diet is a diet in which energy is obtained primarily from fat, while protein and carbohydrates are limited. The lack of carbohydrates causes the body to go into a state of ketosis, in which energy is derived from the breakdown of fat.
Despite some promising benefits, there are concerns that such high fat intake is not heart healthy. Specifically, fat derived from processed foods and animal products contribute to high cholesterol, which increases the risk of heart attack.
This article discusses the facts and risks of the keto diet.
The keto diet dates back to the 1920s when it was used for treatment of seizure disorder in children. It was also found to be useful in controlling blood sugar in people with diabetes.
Emphasis of dietary guidelines in the past several decades has been on a low-fat diet, but the continued rise of obesity and diabetes has renewed interest in the keto diet for its role in weight loss and blood sugar management.
What Is Ketosis?
Food provides macronutrients, which are compounds that are broken down to provide energy for the body. These macronutrients include fats, protein, and carbohydrates (“carbs”).
Fats are broken down into fatty acids, and proteins are broken down into amino acids. Carbohydrates are broken down into simple sugars like glucose, which is used as the primary energy source in the body. This is particularly true in the brain, since fats cannot cross the blood brain barrier to provide energy there.
When carbohydrates are restricted, such as in the keto diet, several things happen. The body starts a process called ketosis to break down fats to provide energy. This breakdown of fats creates ketone bodies, which can be used for energy throughout the body, including in the brain.
At the same time, another process called gluconeogenesis occurs to create glucose by the breakdown of non-carbohydrate substances, like certain amino acids and triglycerides.
A range of carb-restricting diets exist, but a true ketogenic diet is one that induces a state of ketosis. The exact amount of carbohydrate restriction that will induce ketosis varies between individuals.