In this chapter, I will present the principles of the book and explain the importance of diet, goals and physical activity for health and well-being. Diet and physical activity are two fundamental aspects of a healthy life. An adequate diet provides the nutrients necessary for the body to function properly, in addition to helping to prevent chronic diseases, such as diabetes, hypertension and obesity. Physical activity promotes muscle strengthening, improved cardiorespiratory function and the release of endorphins, which bring a feeling of well-being. However, many people have difficulty reconciling these two aspects of life in a healthy way. Some people exercise a lot but don't eat adequately to meet their body's needs, which can lead to reduced performance and an increased risk of injury. Other people eat well but don't exercise enough, which can lead to weight gain and reduced cardiovascular health. The goal of this book is to help readers understand how food and physical activity are related and how they can be combined to achieve the best results in terms of performance and recovery. With this book, you will learn how to adapt your diet to improve your physical performance and recovery after exercise, as well as receive practical tips for incorporating these healthy habits into your daily routine.