￼The epidemics of obesity, metabolic syndrome and type 2 diabetes have worsened over the past decades. During this time our preventive and therapeutic approach (the ‘vaccine’), consisting of a low-fat diet and exercise, has remained fundamentally unchanged. A case is made that these conditions are inter-related and may be caused by a single underlying factor related to the carbohydrate content of diet. The validity of the present approach is challenged when those most knowledgeable in its application succumb to diseases it is meant to prevent. Others argue against the status quo that a low-carbohydrate diet may be more beneficial. A strong belief in the present approach discouraged research into low-carbohydrate diets until recently. Several studies have now demonstrated their benefits and are refuting old claims that they cause harm. Aboriginal people suffer more acutely from the epidemics in question and their dietary history suggests that a sudden increase in carbohydrates is to blame. Recent studies and a case history demonstrate that carbohydrate consumption can drive appetite and over-eating while carbohydrate restriction leads to weight loss and improvement in the markers for metabolic syndrome and type 2 diabetes. The growing evidence in support of low-carbohydrate diets will encounter resistance from economic interests threatened by changes in consumption patterns.