The ketogenic diet (KD), a high-fat, adequate protein, low-carbohydrate diet has been used since 1921 for the treatment of severe medically refractory epilepsy. In the past 15 years, the use of the KD has expanded enormously and a huge amount of clinical evidence of its efficacy is available. The classical KD is however restrictive and therefore alternative more liberal varieties of the classical KD have been developed within the last 8 years. The purpose of this report is to summarise the principles and evidence of effectiveness of the alternative ketogenic diets: Medium Chain Triglyceride (MCT)-KD, modified Atkins diet (MAD) and low glycaemic index treatment (LGIT), compared to the classical KD. The clinical evidence to date suggests that the more liberal versions of the classical KD such as MCT KD, MAD and LGIT have an efficacy close to the classical KD; however, no RCT data are available for MAD and LGIT. This evidence suggests that factors such as age, epilepsy type, lifestyle and resources are important factors in deciding which diet we should start a patient on. This report intends to summarise guidelines based on the evidence available.