Everything we do, from breathing, to exercising and daydreaming requires energy. All energy is produced in the cellular level, and is produced on demand – it cannot be stored. Therefore, everything you do always antagonises this limited resource of energy. Higher level functions such as creativity and rational thinking are not essential for surviving – at least not like breathing, moving and digestion are – and as a result they score lower in the energy priority list. At the same time, such higher level functions require a lot of energy. So how do you achieve and maintain peak mental performance and clarity of thought? By boosting your energy production and minimising the energy expenditure of other functions.