In cities and administration centers there are a lot of restaurants and small cafés so you will find a place to eat without any problem. In remote areas and small villages it is better to book meals in advance.
If you have any food restrictions or are vegetarian or vegan, it is always recommended to inform your tour agent, guide or guesthouse owner in advance.
In remote places vegetarian food is not common and will be monotonous. But in the capital city the choice is much bigger. There are even restaurants and coffee shops specialized on vegetarian food.