The so-called ‘ketogenic diet’ aimed to limit energy derived from carbohydrates, has many variations which cause confusion in the literature and beyond. For ‘intractable’ epilepsy (when seizures cannot be managed completely by drug therapy, also referred to as ‘refractory’, ‘uncontrolled’ or ‘drug-resistant’ epilepsy) the dietary fat to carbohydrate plus protein ratio is held at a ratio of 4:1 or 3:1. Thus promoting fat metabolism to ketone bodies as a primary energy source. This intervention limits glucose availability and consequently neural ‘excitability’ and seizures. Overall, the diet is high-fat, low-carbohydrate, and restricted protein in design. This generally accepted clinical approach (which is based on essentially fasting, historically) was applied and recorded back to the 1920s (for a patient with diabetic ketoacidosis). That observation (and others) initiated the diet applications for epilepsy and thereafter (or perhaps in parallel with) for both (i) weight management (especially the ‘Atkin’s diet) and (ii) enhanced sport performance. Products for weight loss tend to be high-fat but not in the ratios anticipated for seizure management, where, perhaps, brands have been developed that are more cognisant of consumer demands for desirable sensory characteristics than specific nutrient ratios. Whilst ketogenic type diets have been discussed in the context of different applications within the literature, the challenges associated with making and utilising ketogenic products for different applications/needs (with associated compliance) tend not to be addressed. This review addresses some of the challenges associated with creating and consuming ketogenic products, especially for seizure management, which restrict and control energy derived from carbohydrates. It aims to contextualise the issues faced with making and consuming this type of diet with significance generally to individuals interested in this approach to dietary energy regulation, most especially health professionals and people involved in sport nutrition.