In recent years, with the improvement of transportation in Tibet, it's become more and more convenient to be vegetarian. The Tibetan eminent monks were very pleased to see that many Han people even Westerners have a vegetarian tradition, so they began to vigorously promote Tibetan Buddhists to be vegetarian. In this case, many Tibetan monks no longer eat meat. This is a good direction because being vegetarian can reduce the suffering of sentient beings and reduce the chances of sentient beings causing evil karma. Now, all the food served in the scripture halls of the top three monasteries(Ganden, Drepung, and Sera) are vegetarian, and all the people attending the Kalachakra empowerment puja also should have vegetarian.
The monk diet of the Gelug Sect is not invariable. In major Buddhist events and religious ceremonies, the combination of diet is very distinctive.