Replace the pieces of fruit with a variety of vegetables (and treat fruit as nature's candy). A bowl of rice, lentils, quinoa or some other (whole) grain will help you with the proteins and gives you some fiber for a better digestion. A time restricted eating window (commonly known as Intermittent Fasting) can further help you to get leaner.

In your place I'd recommend looking up Fasting and Ketosis – which is the state your body is in after it used up (most of) the sugar stored in your liver and muscles and switches to body fat as fuel. Ketosis takes a little while to get accustomed to – remember though it has been the default for our ancestors, as they did not have sugar in abundance as we in the 21st century do.

Wishing you well for your acting part!