In Lao culture, Lao people usually sit on the floor to eat their meals especially in the countryside. Sometimes they will have a little table to put the food on, but most of the time they put the dishes of food straight on a linen or reed mat so that crumbs don't go on the floor.
The reason why Lao people eat on the floor with no tables and no chairs is because it's part of our tradition that's been carried out for thousands of years. Even during the monarchy era, the Kings of Laos in the past also ate on the floor.
Men always sit down on the floor with their legs crossed and women always squat or have the legs behind the body. Many Laotians think that they feel more relaxed when eating in sitting position on the floor, eating in sitting position also helps to digest better. It can be tough for foreigners who are not used to sitting on the floor for long periods, and they may experience numbness in their legs and stiff knees.
It is also believed that meals are a social affair and people eat in a friendship way on the floor. Another reason is that food is scarce in poor Lao families, and by sitting on the floor this makes everyone closer together and they can reach the food. In Lao culture, food is not served on individual plates like in western countries.
There's also something spriritual to it, because when you go to a temple you must sit on the floor, an act of lowliness and acceptance that you are the disciple and Buddha is greater than you.
In Laos, the floor is usually a clean place because people take off their shoes before entering the house. It's being more common to use tables and chairs in the city, but Lao people like to eat on the floor when there is a party or ceremony and there isn't enough space. There are many Lao style restaurants in Laos where you can sit on the floor to eat, and pillows and cushions are available.