Whether it's because they've reached old age, they're suffering with an allergy or you just think a different premium dog food would better suit their needs, there are many reasons why owners may decide it's time to change their pooch's diet.

However, while a change of food may be the right course of action, your canine companion has a very sensitive stomach and switching their diet without any warning can result in upset stomachs, constipation, diarrhoea or a refusal to eat.

Therefore, if you are going to switch dog foods, then it is essential that you do so gradually to help your pup's system to digest the new brand more easily, by adjusting the enzymes in their digestive tract.

The whole process of switching foods should take about ten days, during which time you should mix the new food with the old type, gradually increasing the proportion of the new food.

So on the first day you should feed one part new food to nine parts old, the second day should be two parts new and eight parts old, and then so on until day ten when your pooch will be eating just the new food.

It is also important to take portion size into account when changing diets. For instance, if you're switching your pup from wet to dry dog food you will not need to provide as much volume-wise, as a dry diet is usually higher in energy.

While most pups will happily chow down whatever food is put in front of them, others may turn their nose up at an unfamiliar taste, so make sure you mix the new and old food in well.

Finally, keep a close eye on your pooch during the first few days on their new diet to pick up on changes such as lethargic behaviour, a dull coat or misty eyes, so if the new food is not working out you'll be able to tell as soon as possible.

Written by: Hannah