There is a profound spiritual science behind offering food. Hindu traditions propound that deities do not physically partake of the food, but rather absorb the 'Praana' (vital life force) of the items the food offering is made of. At Puja time, when the deity is invoked, specific rituals are done to transfer that Praana to the deity as it hovers around the Murthi (consecrated image of a deity) in astral form.
Deva's Kitchen 