My puppy is hungry, not gaining weight, and seems hypoglycemic. Why?
Thanks for using Petco Pet Education Center, formerly Petcoach! I have several thoughts for you regarding Cooper.
1) He's simply hungry. Puppies, just like human children, do not all eat the same and do go through growth spurts. If he is underweight (per a veterinarian), increase the total amount by ~25%. If he is an appropriate weight, but seems to have "stalled out" in the growth department, give it time - again, sometimes weight gain comes in spurts. Your vet can actually calculate a daily calorie goal for Cooper based on his current weight and body condition score if you'd like a more specific recommendation.
2) He has an underlying problem. Liver shunt, heart defect, pancreas problem, or other issues can cause a "failure to thrive" or "runty" puppy. If he truly isn't gaining weight or is underweight despite a good appetite and plenty of food, it's time to talk to your vet about bloodwork and other testing to figure out if there is a problem.
3) He has worms. Worms do not shed eggs 24/7 and it is technically possible to have a "negative" fecal float and still have worms. If he had enough worms to cause problems gaining weight, it is doubtful the float would be negative but still, talk to your vet about a dewormer - just in case. It is much cheaper and easier than all the other testing so you'd hate to miss such a simple fix.
Hope this helps and best of luck to you and Cooper!
Updated on September 23rd, 2025