Puppy feeding and growth
Why is my puppy not gaining weight?
Last updated 23 September 2026 · How we write and check this
Short answer
A puppy that has not gained weight over a week or more may simply be underfed for its current growth phase, but it can also point to intestinal parasites, illness, or stress. Recalculate the food amount against current weight first, then involve a vet if the puppy still is not gaining within a week.
Start with the food amount
The most common and easiest to fix cause is simply feeding an amount that was correct a few weeks ago but has not kept pace with the puppy's growing energy needs. Recalculate the daily total from the food bag's chart using the puppy's current weight, not last month's.
Ruling out parasites
Intestinal worms are extremely common in puppies and can cause poor weight gain even when the puppy is eating well, since parasites compete for the nutrients from every meal. Most puppies are dewormed on a schedule by the breeder or vet, but a recheck is reasonable if weight gain has stalled.
When to involve a vet
If increasing food has not helped within about a week, or the puppy shows other signs like a dull coat, low energy, or loose stools, a vet visit can check for parasites, an underlying illness, or a feeding plan that needs more significant adjustment.
Key takeaways
- Recalculating food amount against current weight is the first thing to check.
- Intestinal parasites are a common, treatable cause of poor weight gain in puppies.
- Increasing food should show results within about a week if that is the whole issue.
- Persistent lack of weight gain alongside other symptoms needs a vet visit.