What would you do if someone you didn't know went out of their way to buy you prepared food that you didn't want?

I have a friend who has a booth at the Flea Market on the weekends. She just posted this on her status. A guy showed up at her booth yesterday and they chatted.

A while later he came back with a burger and fries and water from the little cafe they have there and said, “Here. I brought you some lunch because you’re so nice!” She had bought a fruit cup earlier that was her lunch.
She thanked him but told that guy that she was ”...avoiding that kind of food. (That day anyway).... I did tell him I’d take the water… I felt so awkward!!!”

I know she eats “that kind of food” on other days. Is that what you would have done? I would have offered to split the food with him and explain I can’t eat that much in one setting! (Which is true.) Then I’d eat as much of my half as I could.