In this episode, we delve into the principles and practice of Fasting, including every other day fast and time-restricted feeding, also known as intermittent fasting. We explore the evidence on how confining your eating periods to specific parts of the day-or fasting for extended durations-affects outcomes such as weight loss, specifically fat loss, liver health, mental clarity, muscle health, longevity, among others. We'll discuss the concept of being in a "fasted" state, how it connects to blood glucose levels and their subsequent effects, and how the intensity of fasting can be modulated with activities like varying exercises or glucose disposal agents. We'll also discuss the most effective fasting regimen, covering both the essential aspects and the variable elements that are dependent on context. These elements help to maximize the advantages of a fasting or time-restricted eating plan. Additionally, we'll touch on what does or doesn't interrupt a fast, along with the impact of fasting on hormones such as testosterone and cortisol. We will examine how various eating windows influence fasting results, and consider why the conventional 8-hour eating window may be the best choice. To give you a clearer understanding, we'll explain the underlying mechanisms and provide you with practical tools to help you identify the best fasting duration and timing that suits you.