Follow this Weight Loss Timeline to a Tee for Results that Stick

Day 1:

To lean out for life, set a realistic goal. "You can see great improvements in health by losing between 5 and 15 percent of your body weight, and you're more likely to keep those pounds off," says Donna Ryan, an obesity researcher at Pennington Biomedical Research Center.

5 weeks:

Ghrelin, a hormone that revs appetite, begins to spike after you start cutting cals, making it hard to stick to your plan. 

Stay satiated by "keeping low-calorie foods around, like vegetables and fruits, to snack on when your stomach growls," says Robert Kushner, M.D., an obesity specialist at Northwestern University.

6 months:

Bored with eating the same dang foods over and over again? Yeah, it's bound to happen now. Mix up your meals (by, say, adding back brown rice to lunch if you've been low-carbing) the wiggle room will make you less likely to bail, says Kushner. (Get after your weight-loss goals with Women's Health's Body Clock Diet. )

9 months:

By this point, you're probably settling at a manageable weight. Shift your focus from cutting food calories (tough to do forever) to burning the calories you consume by upping exercise. 

"Aim for an hour a day of moderate activity, six days a week, to keep weight off long-term," says Ryan.