Over 50% of an Orangutan's diet is made up of fruit.  Orangutans travel as far and as fast as they need to in their home ranges to find food.  Although fruit is their primary food source, Orangutans have been known to eat up to 400 different things!  When the Orangutan is not spending time resting or sleeping during the day, they are foraging for food.  This is necessary because Orangutans have a high caloric need and high quality food is not always readily available.  Orangutans belong to the group of Primates called "Nutcracker Primates" which crack open hard-coated fruits for food (3).  In the wild, Orangutans have shown intelligence by using leaves of trees as gloves when handling fruit covered in sharp points. 

Some of an Orangutan's Popular Food Items

sap young leaves flowers
honey shoots stems
seeds nuts bamboo
fungus pith of plants bark
soil termites ants
eggs invertebrates sometimes hunt small mammals