Many owners ignore sudden weight loss in their dogs, but it's one of the most alarming health signs. Even if they're eating well, they're still losing weight — it could mean diabetes, kidney problems, parasites, thyroid disorders, or even cancer. In many cases, early diagnosis can help control the disease and give your dog many years of healthy life. In this article, you'll learn what a healthy weight range is, how much weight loss per week is dangerous, and what diet and lifestyle changes can help your dog get back on track. Ignoring it can lead to regret later — so it's wise to be smart in the beginning.