Excessive Food Intake (Overnutrition or Polyphagia)

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This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Too much food intake can be harmful for your pet - but why do some pets overeat ?

Pets should only eat enough food to meet their energy requirements. In adult animals excessive food intake can result  in obesity , and in young puppies and kittens excessive food intake leads to increased rate of growth as well as obesity. Both these are detrimental to health for various reasons. Increased appetite and polyphagia also occurs when an animal is unable to digest, absorb or utilise nutrients properly.

There are many causes of overeating, and one of the most common is :

Bad feeding practices

  • Allowing continuous access to unlimited amounts of food (called ad libitum feeding) - is likely to encourage your pet to overeat. Owners often do this with dry foods because several days supply of  food can be left in open feeding dishes, or feed dispensers  for long periods without going off.
  • Feeding frequent tit-bits and treats can induce overnutrition particularly if high fat content foods are given eg meat offcuts, or fried food left-overs.
  • Feeding very palatable  foods can encourage over eating

Other causes of overeating include :

Endocrine (hormonal) disorders:

  • Diabetes mellitus 
  • Hyperthyroidism 
  • Hyperadrenocorticism (Cushings Disease) 

Also, gastrointestinal diseases :

  • Pancreatic atrophy
  • Malabsorption 

And, behavioural causes

In both cats and dogs excessive appetite due to unknown causes has been reported. In some breeds (such as the Labrador Retriever) it has been suggested by some authors that there may be a genetic predisposition to eat excessively and therefore to develop obesity.

In young animals competition at feeding time can lead to overeating in the most dominant individuals. It is well documented that rapid growth rates are detrimental to health - for example large and giant breed puppies that grow fastest are more likely to develop hip dysplasia than their littermates.

Consequences of polyphagia

Most causes of polyphagia will result in the development of obesity  - exceptions are in the case of gastrointestinal disease or diabetes mellitus when weight loss is likely to be seen.


Avoid bad feeding practices. Prevent access to excessive amounts of food.

Have your pet examined by your veterinarian in case  there is an underlying disease process which needs to be treated appropriately. 

Modify undesirable behaviour eg feed dominant puppies separately to the rest of the litter.


Updated October 2013