During the day-trip the boatman will stop at a restaurant in a canal in the backwaters where you can have an Indian meal. Try the river crabs or fish, accompanied by a coconut liquor.
If you get thirsty while on the boat, ask the boatman to buy a fresh coconut from one of the farmers. The seller will cut it, put a straw in it, and there you have it: a fresh coconut juice. When you are done with the coconut milk, you can ask the farmer to cut the coconut, and eat the flesh.