High energy intake combined with low physical activity generates positive energy balance, which, when maintained, favors obesity, a highly prevalent morbidity linked to development of non-communicable chronic diseases, including chronic kidney disease (CKD). Among many factors contributing to disproportionally high energy intakes and thereby to the obesity epidemic, the type and degree of food processing play an important role. Ultra-processed foods (UPF) are industrialized and quite often high-energy-dense products with added sugar, salt, unhealthy fats, and food additives formulated to be palatable or hyper-palatable. UPF can trigger an addictive eating behavior and is typically characterized by an increase energy intake. Furthermore, high consumption of UPF, a hallmark of 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 uremic metabolic derangements, such as insulin resistance, metabolic acidosis, hypertension, dysbiosis, hyperkalemia, and hyperphosphatemia. Global sales of UPF per capita increased in all continents in the last 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 UPF in activating hedonic eating, and its main implications for health, especially for kidney health and metabolic complications of CKD. We also present various aspects of consequences of UPF on planetary health and discuss future directions for research to bring awareness of the harms of UPFs within the CKD scenario.