Looking (and feeling) better on the beach is a perfectly valid reason for wanting to slim down, but it might not be enough to keep you inspired for the long haul. "Come up with a running list of all the things that are better about your life when you're at a lighter weight," Nichols says. Your list might include things like being healthier, having more stamina, improving your confidence, shopping for fun fashions, keeping up with or setting a good example for your kids, or knocking something off your bucket list like hiking the Grand Canyon, which is much easier when you're fit and at a healthy weight. Once you've written out your detailed list, keep it handy and read it often, especially when you're feeling particularly drained, to remind yourself why it's worth staying on track, she says.