This book unlocks the secrets of a powerful and sustainable brain, as well as explores the concept of a hybrid-powered brain and the transformative potential of the "Small Ketogenic" system. Supplying the brain with an ample energy substrate is vital for a positive mindset and a fulfilling day. Adequate energy fuels sharp thinking and clear judgement, while an energy-deficient brain leads to a variety of problems. Low blood glucose levels make it difficult to remember and amplify negative emotions. Delve into the brain's often-overlooked energy system to avoid these situations. The human brain functions on two energy systems: glucose from carbohydrates and ketone bodies from fats. These systems complement each other, and activating the hybrid system is surprisingly simple. Adopting the "Small Ketogenic" means extending the intervals between meals and allowing for a slight feeling of hunger within a reasonable range. This approach preserves cognitive function to the maximum. Inspired by the longevity of individuals in certain villages, the hybrid-powered brain enhances mental vitality. These villagers lead vibrant lives fuelled by their powerful minds. Maintaining ketone body concentrations between 0.2-0.5 mM ensures an active and calm brain. By making slight adjustments in eating habits, and adopting the "Small Ketogenic", we can achieve healthy longevity. This sustainable approach boosts the brain and promotes optimal health effects. Embark on a transformative journey of self-improvement and discover the true potential of your brain. This book revolutionises the way you perceive and care for your brain, leading you to a sustainable and fulfilling cognitive existence.