At the beginning of the last century obesity and type 2 diabetes were treated quite successfully using low-carbohydrate diets. Following the discovery of insulin, the carbohydrate content of the diabetic diet became more liberal, as glycaemia and glycosuria could be controlled, more or less well, with hypoglycaemic medication and insulin treatment. Later, saturated fats and high-plasma cholesterol concentrations were implicated in cardiovascular disease and since then high-carbohydrate diets have become synonymous with 'health' and have been conventional nutrition doctrine for the past 40 years. In spite of this, the prevalence of some non-communicable metabolic diseases have increased to epidemic proportions and have led an increasing number of researchers in the fields of medicine and nutrition to challenge the validity of present-day dietary guidelines. There is increasing evidence that diets with a lower, or even very-low, carbohydrate content can help overweight and obese individuals to lose and maintain lost weight, diabetics to control blood glucose with more ease and prevent the development of diabetic complications, while at the same time improving blood lipid profiles and biomarkers of cardiovascular risk. The present review considers the evolution of our diet and questions whether high-carbohydrate diets are indeed synonymous with health.