Dog Appetite Change: When It Signals Illness

1. The Evolutionary Drive: Why Dogs "Should" Be Hungry

In the wild, canines are opportunistic scavengers. Their biology is wired to eat whenever food is available. Therefore, a dog refusing food is one of the most reliable indicators of systemic illness. In clinical terms, we look at Anorexia (no eating) vs. Hyporexia (picky eating).

2. The "Selective Eater" Fallacy

A common owner mistake is saying, "He won't eat his kibble, but he'll eat a piece of chicken, so he's just being stubborn." In reality, the dog is likely experiencing nausea. High-value human food can sometimes trigger a "survival" eating response that overrides nausea, but the refusal of their standard diet is a clinical sign of Digestive Conditions.

3. Top Pathological Causes for Appetite Change

Metabolic Issues: Kidney or Liver failure causes a buildup of metabolic waste in the blood (uremia), which makes the dog feel profoundly nauseous.
Gastrointestinal Obstruction: If a dog eats a foreign object (sock, toy), the blockage stops motility. This is a surgical Emergency.
Dental & Oral Pain: Sometimes the hunger is there, but the physical act of chewing is excruciating due to abscesses or fractured teeth.

4. The Distended Abdomen: The 15-Minute Rule

If your dog stops eating and their abdomen looks bloated or feels hard, this is not a "wait and see" situation.

GDV (Bloat): This is where the stomach twists on itself. It is a fatal condition within hours.
Signs: Non-productive retching (trying to vomit but nothing comes up) and a sudden drop in appetite. This requires an immediate In-Person Care visit.

5. Nutrition & Transitioning: When to Worry

If you have recently changed diets, a temporary drop in appetite might be linked to Nutrition & Diet-Related Health or food allergies. However, if the refusal lasts more than 24 hours, the risk of dehydration and hepatic lipidosis (especially in smaller dogs) increases.

My dog won’t eat kibble but will eat chicken—should I worry? ▾

Yes. That pattern often points to nausea or mouth pain rather than “stubbornness.” If it lasts more than 24 hours or your dog seems uncomfortable, an evaluation can prevent a small issue from turning into a bigger one.

What’s the difference between anorexia and hyporexia in dogs? ▾

Anorexia means your dog is not eating at all. Hyporexia means they’re eating less than normal or only eating selectively. Both can be clinically significant, especially if the change is sudden or persistent.

When is loss of appetite an emergency? ▾

Treat it as urgent if appetite loss happens with repeated vomiting, a bloated/tight abdomen, unproductive retching, collapse, pale gums, or severe weakness. These can signal obstruction or GDV and require immediate in-person emergency care.

Can I try changing food first if my dog isn’t eating? ▾

If you recently changed diets, a short dip can happen—but avoid constant switching. If refusal lasts more than 24 hours, or your dog is lethargic, vomiting, painful, or bloated, book a RexVet online appointment to triage and decide if emergency care is needed.

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