Ultraprocessed foods and chronic kidney disease - double trouble

Lay Summary When the diet we eat has more calories than the energy spent by the body, obesity may develop. Obesity increases the risk of developing chronic kidney disease (CKD). Ultraprocessed foods (UPFs) are among the products that can increase energy intake. UPFs include industrialized foods such as carbonated soft drinks, candies, ice cream, mass-produced packaged breads and buns, margarines and other ready-to-eat foods. In some UPFs, sugar is replaced for non-caloric artificial sweeteners, which may not add as many calories, but are still unhealthy. For individuals with CKD, a diet with large amounts of UPFs can trigger or worsen blood pressure and increase blood concentrations of glucose, potassium and phosphate. Therefore we recommend that patients with CKD avoid or reduce the use of UPFs in their diet and prefer home-made meals. High energy intake combined with low physical activity generates positive energy balance, which, when maintained, favours obesity, a highly prevalent morbidity linked to development of non-communicable chronic diseases, including chronic kidney disease (CKD). Among many factors contributing to disproportionately high energy intakes, and thereby to the obesity epidemic, the type and degree of food processing play an important role. Ultraprocessed foods (UPFs) are industrialized and quite often high-energy-dense products with added sugar, salt, unhealthy fats and food additives formulated to be palatable or hyperpalatable. UPFs can trigger an addictive eating behaviour and is typically characterized by an increase in energy intake. Furthermore, high consumption of UPFs, a hallmark of a Western diet, results in diets with poor quality. A high UPF intake is associated with higher risk for CKD. In addition, UPF consumption by patients with CKD is likely to predispose and/or to exacerbate uraemic metabolic derangements, such as insulin resistance, metabolic acidosis, hypertension, dysbiosis, hyperkalaemia and hyperphosphatemia. Global sales of UPFs per capita increased in all continents in recent decades. This is an important factor responsible for the nutrition transition, with home-made meals being replaced by ready-to-eat products. In this review we discuss the potential risk of UPFs in activating hedonic eating and their main implications for health, especially for kidney health and metabolic complications of CKD. We also present various aspects of consequences of UPFs on planetary health and discuss future directions for research to bring awareness of the harms of UPFs within the CKD scenario.