The relative contribution of nutrition-related chronic diseases to the total disease burden of the society and the healthcare costs have risen continuously over the last decades. This challenge requires to explore and use the potential of dietary prevention of diseases such as obesity, type 2 diabetes, dyslipidaemia, cardiovascular disease and cancer. This evidence-based guideline systematically assessed the potential role of carbohydrates in the primary prevention of these diseases. The major findings were: a high consumption of sugar-sweetened beverages increases the risk of obesity and type 2 diabetes (strength of evidence: probable), whereas a high dietary fibre intake, mainly from whole-grain products, reduces the risk of obesity, type 2 diabetes, dyslipidaemia, hypertension, coronary heart disease and colorectal cancer (strength of evidence: probable and convincing, respectively). The practical consequences for current dietary recommendations are presented.