What food rules do Buddhists follow?

Avowed Buddhists are strict vegetarian.

Answer:

Many people think Buddhists eat only plain rice or hold to a strictly vegetarian diet (with no exceptions). In truth Buddhists are inclined to a vegetarian diet as eating meat implies that animals have suffered. This does not hold true in all cases. HH the Dalai Lama only came to a strictly vegetarian diet later in life as, in Tibet (his homeland), the opportunity for pursuing such a diet is limited.

The only foods outside of a Buddhist's diet would be alcoholic drinks, and food prepared from animals slaughtered specifically at the request of the Buddhist.

It is a point of propriety that Buddhists will eat whatever food is given to them in good faith - as is demonstrated by the story that the Buddha himself died of eating tainted meat given to him for a meal.