That depends on your work schedule, home life and personal preferences. Some people find that starting on a Monday and finishing on a Friday is best as their work distracts them and gives them something to focus on besides food. Other people like starting the program in the middle of the week and finishing on a Sunday night. There’s no right or wrong answer here. You may want to keep in mind that most people find days two and three to be more challenging than days four and five, so make your plans accordingly.