This video explains the 5 levels of chronic kidney disease (CKD) in cats in a clear, evidence-based way, focusing on what is actually happening inside the body at each stage and challenging the common advice to simply reduce protein intake, by breaking down how protein metabolism works, including the conversion of amino acids into ammonia and then into urea via the liver, and how the kidneys are responsible for excreting that urea, while also explaining why excessive protein restriction can lead to muscle loss, increased internal ammonia production, misleading improvements in bloodwork, and faster overall decline, especially in earlier stages of CKD, where maintaining high-quality, highly digestible animal protein is critical for preserving muscle mass and metabolic health, alongside managing phosphorus intake, hydration, and calorie sufficiency, making this a comprehensive, long-form guide for cat owners who want to understand kidney disease properly and make better nutritional decisions rather than blindly following outdated or oversimplified recommendations.