Additionally, no fruit is off-limits once you've completed the 31 days. "You can have a sandwich in week four, which just makes things easier," Alpert said. Week four is the home stretch, when you can enjoy two starches per day, including bread and rice, in addition to high-fiber crackers. For week three, you can add grains such as barley, quinoa and oatmeal, and even some more fruit including grapes and clementines. You can also have another glass of red wine during the week and an ounce of dark chocolate each day.