Degus have very specific dietary requirements, so you must make sure you feed them foods that they are used to. Good quality hay (Timothy hay) and a mixture of guinea pig and chinchilla pellets will provide your degu with a variety of seeds, cereals, grains, dried vegetables and most importantly Vitamin C, which will keep their teeth and gums healthy. Root vegetables like carrot, swede, sweet potato, and parsnip can be offered every other day. Make sure you feed your degus twice a day (in the morning and in the evening).
Fatty foods and foods high in sugars should be avoided as degus can't break down the sugar like other animals can. Foods such as peanuts, sunflower seeds, fruits and carbohydrates should also be avoided — so don't buy cereal-type foods that include these. Sugary foods can cause diabetes and will make your degus very ill. This also means that any chinchilla or guinea pig foods containing molasses should never be fed to your degus. If you introduce new foods to their diet, mix a small quantity with their current food gradually so that you avoid causing them tummy upsets.
You will need to make sure you purchase a heavy, sturdy food bowl so that it doesn't tip over in the cage. Any uneaten food should also be removed each day, and the bowl and water bottle cleaned and refilled every day. A water bottle with a metal spout that attaches to the outside of the cage is the most suitable. To keep their vitamin levels up, try adding some supplements to their water.