Nutritional ketosis is a metabolic state in which the body burns fat as its primary fuel source, rather than carbohydrates. This process involves the breakdown of fats into molecules called ketone bodies, which are then used by cells for energy. Nutritional ketosis typically occurs when someone follows a low-carb diet and consumes fewer calories than they burn, causing their body to shift towards using fat as fuel instead of carbohydrates. This state is often associated with weight loss, improved mental clarity, and increased energy levels. However, it's important for individuals to maintain a healthy balance between nutritional ketosis and other metabolic processes to ensure optimal health.