Does the definition of human ultra-processed foods apply to dog and cat foods? A review of pet food processing techniques, their impact on health, and a call for pet food processing classification

Evidence linking higher intake of ultra-processed foods (UPFs) with increased risk of chronic diseases in humans has grown since the establishment of the NOVA classification and its widespread adoption in nutrition research. Extruded dry and wet diets for cats and dogs (commonly known as kibble and canned/tinned foods) share many features with human UPFs. As these formats are the predominant pet diets in developed countries, similar concerns have been raised. However, progress in this field is constrained by the absence of a clear definition of UPFs in pet nutrition. This Perspective outlines the human UPF definition, with emphasis on the NOVA classification, and reviews mechanisms proposed to explain their negative health impacts in humans. We then compile the current state of knowledge on pet food processing across both traditional dry and wet diets and emerging dietary formats, illustrating the diversity of products available and their potential implications for canine and feline health. We argue that findings from human UPF research cannot be directly extrapolated to dogs and cats, but highlight the need to develop an objective, systematic classification of pet foods based on processing levels. Such a framework would enable research into health effects of processing in companion animals while incorporating the perspectives of manufacturers, regulators, and researchers. Finally, we propose a set of key factors that should inform this classification to reflect the diversity of pet food formats and facilitate its acceptance and use within the veterinary nutrition and pet food research communities.