Fuller has struggled for full match fitness since dislocating his shoulder in February and was prevented from doing a full pre-season fitness programme after spending large parts of the summer with the Jamaica national squad.
Pulis has now told the 29-year-old to lose weight if he wants to repeat his performance last season, when he finished as the Potters' leading scorer with 11 goals, and Fuller is ready to rise to the challenge.
Talking to BBC Stoke, Fuller said: "The gaffer said that I've gained a bit of weight and that I need to lose some.
"I drink a lot of protein shakes and things like that. I need the weight because my main strength is my power."
"I know I need to pick my fitness up because I didn't have a proper pre-season," he added.
"In games, the lads keep putting the ball in the corners so I just keep chasing after it.
"I know that I need to get some running done. When I'm on the pitch I just run and run to try and make something out of nothing for the team."