Book excerpt: See results in three weeks, with a revolutionary keto diet program from Dr. Michael Mosley, the #1 New York Times bestselling author of The Fast Diet. Recent studies have shown that a keto diet not only produces significant—and rapid—weight loss, but also has many other benefits for long-term health. But it must be done the right way. In 21-Day Keto Magic, Dr. Mosley presents the latest science on the ketogenic diet—a diet high in fat and protein and very low in carbs—explaining how it works and why it is so good for you. The aim of a keto regime is to kickstart a process called ketosis, whereby your body goes from burning sugar to burning fat for fuel. Flipping this metabolic switch has the added advantage of making you feel less hungry, which makes the diet highly motivating and relatively easy to sustain. 21-Day Keto Magic offers a detailed, step-by-step program, along with easy tips and clear advice on which foods support ketosis and which ones stop it, how to tell if you are producing ketones, and how to ensure that you're following the diet safely. There are also 50 delicious recipes from Michael's wife, Dr. Clare Bailey, as well as shopping lists, weekly meal planners, and all the other tools you need to ditch stubborn fat and transform your health for life.