The Kuku Kuku no Mi is a Paramecia-type Devil Fruit that allows the user to turn objects into food. It was eaten by Streusen. With this fruit, the user has easy access to food to feed themselves and others just by transforming any object into food. The user does not even need to cook the food. The user can also turn an object into food in order to make it less dangerous or otherwise more useful.
However, while the food created by the user can provide nourishment, it apparently does not taste good, as Big Mom remarked, though that could just stem from Big Mom's very demanding palate. Other than that, the user is still affected by the standard Devil Fruit weakness.