The practice of offering food to monks is most visible in Theravada buddhist countries like Laos and Thailand, where the practice sustains large monastic communities. They walk single file, oldest first, carrying their alms bowls in front of them. Laypeople wait for them, sometimes kneeling, and place food, flowers or incense sticks in the bowls.
Tak Bat - A Venerable Tradition in Luang Prabang
It's one of the most vivid images of Laos - from 5:30 in the morning onward, silent lines of saffron-clad monks walk down the streets of Luang Prabang to collect alms. The locals are there ahead of them, ready with bowls full of the Lao staple sticky rice; every monk gets a scoopful in their bowl. With almost eighty temples in Luang Prabang alone, this adds up to hundreds of monks, who take different routes depending on where in town their temple stands. The routes that walk through Th Sakkarin and Th Kamal are among the most viewed by tourists, although the ritual occurs all around Luang Prabang.
Each monk carries a large lidded bowl, which is attached to a strap hanging from the monk's shoulder. As monks file past the line of almsgivers - who are usually sitting or kneeling on the street - these containers are reverently filled with handfuls of sticky rice or bananas, incense and even money.
The best rice for the tak bat ritual is prepared by the almsgivers themselves. The locals wake up early to prepare a batch of sticky rice, which they then scoop generously into each monk's bowl as the line files past.
The ritual is done in silence; the almsgivers do not speak, nor do the monks. The monks walk in meditation, and the almsgivers reciprocate with respect by not disturbing the monk's meditative peace. For hundreds of years, the ritual has cemented the symbiotic relationship between the monks and the almsgivers who maintain them - by feeding the monks and helping the laypeople make merit, tak bat supports both the monks (who need the food) and the almsgivers (who need spiritual redemption).
The upsurge of tourism in Luang Prabang has endangered the tak bat ceremony, as many tourists approach the ritual not as a religious ceremony to be respected, but as a cultural show to enjoy.
Tourists often jostle the monks, breaking their meditation; they take flash pictures of the line; and they disrupt the ritual with their inapppropriate noise, actions and dress.
As a result, fewer local are inclined to take part, because they refuse to be part of a dog-and-pony show for tourists. Some Lao officials are considering stopping the tradition because of the deep offense caused by tourists'beastly behavior.(http://goseasia.about.com/od/laos/a/Tak-Bat-Luang-Prabang-Laos.htm)