Guinea Pig Nutrition

long haired guinea pig with a piece of tomato

The health of your guinea pigs will be very much a result of what you give them to eat. It is important that they get the correct nutrition to maintain their wellbeing. 

Fiber and Protein

The main part of a guinea pig’s diet is of fiber and protein with fiber constituting most of their intake. A guinea pig’s diet should be higher in fiber than protein and low in sugar, carbs and rich fats.

Fiber is incredibly important for guinea pigs as it helps move their food through the gut properly. Hay, which is rich in fiber, also helps grind down their teeth and prevents them from overgrowing. Your guinea pig’s pellet food should also have a high fiber content.

The fresh food you feed to your guinea pigs will also contribute to their daily fiber intake.

Baileys enjoying some parsley


Cavies can tolerate fats but should only constitute around 3-5% of their daily intake as excess fat can be converted into glucose and, again, upset the delicately balanced flora of their stomach. Check your pellet food which should have around 1-2% fat included in the ingredients.


Guinea pigs also require calcium, magnesium and phosphorous. These nutrients can be found in your dried guinea pig pellet food but, more importantly, can be found abundantly in fresh vegetables and fruit


Many guinea pig owners believe that a diet that is rich in calcium causes bladder stones or bladder sludge (white deposits in their urine) but it’s oxalate-rich food such as spinach, that is the main issue.

Calcium is an essential mineral that guinea pigs need to keep their constantly-growing teeth healthy as well as keeping their bones strong and healthy too. So, rather than trying to cut down on calcium-rich fresh veggies, it is better to make sure your guinea pig has a wide variety of daily fresh food or foraged weeds and plants so their diet is well-balanced.

Guinea pig eating grass and herbs from a pot
Sunny Pig eating grass and herbs

Don’t overfeed your guinea pigs with pellet food and make sure they have a constantly supply of timothy or meadow hay. Avoid calcium-rich alfalfa which is only really suitable for baby guinea pigs and nursing mothers.


Phosphorous is also an essential component of their diet and should be provided in a ratio of 1:1.5 when combined with calcium. An inverse ratio can cause digestive and urinary problems.

Vitamin C

Your guinea pig requires around 10-30mg of vitamin C a day. Guinea pigs cannot produce this essential compound so it is important that the food you provide your pet with contains vitamin C.

Supplements are rarely needed when a guinea pig is fed a good variety of fresh daily vegetables, so we don’t recommend supplementing your guinea pig’s diet with chewable tablets or with drops that are added to their water unless recommended by a vet.

Adding vitamin C drops to the water may result in them drinking less if they don’t like the taste which could lead to serious health problems.