The phrase "Fat for Fuel" refers to a metabolic state in which the body uses dietary fat as its primary source of energy instead of carbohydrates. This process is called keto-adaptation, and it occurs when an individual follows a low-carb or ketogenic diet for several days or weeks. During this time, the body enters a state of nutritional ketosis where it burns fat as its primary fuel source instead of carbohydrates. This can lead to weight loss and improved health outcomes such as increased energy levels, better mental clarity, and reduced inflammation.