I heard that Balinese Hindus always include non-vegetarian in their diet including pork and beef. Is this true?
Yes, they do. Only their brāhmaṇas and kṣatriyas are restricted from eating beef and pork. The rest can eat pretty much whatever they want. From Island of Bali by Miguel Covarrubias:
A Brahmanic priest we occasionally visited told us that under no circumstances may Balinese eat the following: "human flesh, tigers, monkeys, dogs, crocodiles, mice, snakes, frogs, certain poisonous fish, leeches, stinging insects, crows, eagles, owls, and in general all birds with moustaches"! We assured him nobody ate such things, but he remarked that it was well to keep it in mind anyway. Being of the highest caste and a priest besides, he could not touch the flesh of cows, bulls, and pork, eat in the streets or in the market, drink alcohol, or even taste the food from offerings from which the essence had been consumed by the gods. Members of the high nobility — Brahmanas and Satrias — are forbidden to eat beef, but many of the lesser Gustis do not mind eating it.
Outside of these prohibitions the common people eat everything that walks, swims, flies, or crawls. Chicken, duck, pork, and more rarely beef and buffalo are the meats most commonly eaten.
The original castes still remain as subdivisions of the fourth and lowest of the Hindu castes, the Sudras, who constitute about ninety-three per cent of the population of Bali.
The Hindu-Balinese nobility is divided into the three well-known groups: the priests, Brahmanas (Brahmins of India); the ruling royalty, Satrias (Ksatriyas); and the military class, Wesias (Vesiya). They are supposed to originate directly from the gods.
According to the legends, the Brahmanas sprang out of the mouth of Brahma, the Satria from his arms, and the Wesia from his feet. Perhaps the reason why the common people look upon their nobility with such respect is that they have still an unshaken belief in their divine origin.