How do I handle food for the pet and house sitter? Is it a fixed amount per day? Any suggestions?

You don't have to leave food for the sitter unless you'd like to. Just be sure that you have enough food/treats for your dog. Before the stay, you should go over what kind of access and/or privileges the sitter can take: use of kitchen, TV, bedroom, etc., and what other responsibilities you'd like the sitter to assume, like watering plants, dealing with mail, etc.

There's another question about house sitting here. Deb A and others have described how they perform house sitting functions and what supplies they bring. I'll go look for that answer to link here for you.

Finally found the question:

https://www.rover.com/community/quest...

This should give you an idea of how the sitters approach their assignments and what you might like to provide for them.

You can leave it to your own preference whether to provide food or not. I'm a sitter and for the majority of my stays I provide my own food. Here and there a client will say, "Help yourself to the food in the fridge or cupboards." and if I feel comfortable with that, I will commandeer an item or two :-D But I'm a shy, reserved person so most of the time I don't feel right eating up someone else's food.

Definitely have enough food and treats for your pet to cover your stay. You might want to tell the sitter where you buy food and maybe leave some money in case they run out and need to get more.

As the others have said about food for the sitter, this is something that should be discussed ahead of time, along with other aspects of them staying in your home. What other duties would you like them to do (mail, watering plants)? Can they leave to run errands or go back to their house for short periods of time? Be sure to let them know if you have any service people coming to the house, such as lawn, maid, maintenance, etc. and how they are to handle that situation. Explain how to operate any kitchen or other appliances you give permission to use.