Obesity along with chronic non-communicable diseases such as diabetes, hypertension, cancer and cardiovascular disease, constitute the main public health problem at present. Excess weight is classically attributed to an imbalance between calories ingested and calories expended, and consequently, it is proposed as a treatment for obesity, reducing caloric intake - hypocaloric diets - and increasing energy expenditure through physical activity. However, energy imbalance is not the primary cause of obesity, but simply a consequence of the expansion of fat mass. Both the hunger and lack of physical activity observed in the obese are only symptoms resulting from the activation of the mechanisms responsible for accumulating fat. Ultra-processed foods are the main vectors of obesity, since they often set in motion a set of metabolic changes that include insulin elevation, resistance to leptin and deregulation of the reward system, among other mechanisms that lead to increase in fat mass. The only effective treatment capable of preventing and treating obesity and associated chronic non-communicable diseases consists in the adoption of a food system based mainly on minimally processed natural foods.