Being prepped to make a life changeâ€”like knowing 15 ways to change eating habits in a dayâ€”will help you get started. But being confident that you know the exact day may be more of a gut feeling: Often the most successful dieters start because of a wakeup call, says Amy Shapiro, MS, RD, founder of Real Nutrition NYC. Maybe you went to the doctor and he told you that you’d have to go on medication unless you did something to get your cholesterol down, or a family member has a heart-to-heart with you about your health, or a friend gets sick. ‘When these things happen you set a goal that’s more emotional rather than weight-based, and that’s often more successful,’ explains Shapiro. ‘If things get rough along the way, you can remind yourself why you’re on this journey,’ she says.