The ketogenic diet may seem like the latest weight-loss craze, but it’s actually been around for nearly a century. Developed in the 1920s, this ultra-low-carb, high-fat eating plan was originally used to treat seizures in people with epilepsy. Today, it’s getting some serious attention for an entirely different reason. “There’s growing research showing that the ketogenic diet is effective for managing blood sugar in people with diabetes,” says William Yancy, MD, program director at the Duke Diet and Fitness Center in Durham, North Carolina. “However, because we don’t have studies [lasting] longer than two or three years, we don’t know what can happen with regard to complications over longer periods of time.”
In terms of weight loss, you may be interested in trying the ketogenic diet because you’ve heard that it can make a big impact right away. And that’s true. “Ketogenic diets will cause you to lose weight within the first week,” says Mattinson. She explains that your body will first use up all of its glycogen stores (the storage form of carbohydrate). With depleted glycogen, you’ll drop water weight. While it can be motivating to see the number on the scale go down (often dramatically), do keep in mind that most of this is water loss initially.
On a ketogenic diet, your entire body switches its fuel supply to run mostly on fat, burning fat 24-7. When insulin levels become very low, fat burning can increase dramatically. It becomes easier to access your fat stores to burn them off. This is great if you’re trying to lose weight, but there are also other less obvious benefits, such as less hunger and a steady supply of energy. This may help keep you alert and focused.