This chapter presents the core principles underpinning the modified ketogenic diet (MKD)-UK approach, but diet centers in different parts of the United Kingdom, and indeed across the world, may navigate the initiation, prescription, and fine-tuning of their hybrid keto journeys slightly differently. The MKD-UK prescription process starts out with an estimation of individual energy requirements, just like the classic KD. This is then translated into an approximate distribution of 5% energy coming from carbohydrates, 75% from fat, and 20% from protein. The guidance for protein is simply to include a good quality source at each meal, choosing moderate-sized portions with no weighing. Therefore, the MKD-UK delivers an element of the classic KD control over the most antiketogenic (carbohydrate) and proketogenic (fat) components of the diet, while maintaining the more liberal modified Atkins diet approach to protein (although adjustment to protein portions may come along during the fine-tuning phase, if required).