Kevin McLin (a former publicist for the Jackson family) stated that Michael Jackson generally liked eating turkey burgers, Chinese food, a lot of vegetables, but he avoided red meat.
Also, right after a concert, sources close to him revealed that he used to eat watermelon (backstage) as a way for him to replenish the fluids that he just lost on stage while performing.
This suggests that also right after each 'This Is It' show, he would eat watermelon (backstage) for the same reason.
Michael Jackson also liked to order and eat fish sandwich from McDonald's (especially, while working in the recording studio).
One of the singer's favourite meals generally was chicken breast (chicken breast was also his last meal on Earth).
It is interesting to note that during Michael Jackson's last week on Earth, Randy Phillips hired a guy whose sole purpose was to remind the singer to eat.