That's why so many diets that start as New Year's resolutions drown in pitchers of green beer on St. Patrick's Day, if not sooner.
Logically, there's no reason why a diet should end with a single slipup. What's the worst that can happen? It sets you back a day or two. If your goal is permanent weight loss, what you do six days a week should matter more than what happens on the seventh.
In fact, some in the field suggest that a good diet plan should include wiggle room. In other words, you should plan to give yourself an occasional break—in the form of a cheat meal.
The most popular example is Body for Life. Author Bill Phillips advised readers to follow his strict high-protein, low-fat plan six days a week and then use the seventh as a "free day" to eat whatever they wanted.
Pizza, pancakes, "a Big Mac or two for lunch"—it was all on the table. Those free days, Phillips wrote, "may help convince your body that it is not starving." But even more important is the psychology behind a break. "You don't want to create standards you can't meet," he added.
The 12-week Body for Life program was put to the test in a Skidmore College study. Even with 12 days of anything-goes eating, people on the program reduced their daily calories by 29 percent and lost an average of 11 pounds. But something interesting happened along the way: "Many of the participants grew out of the free-day eating plan early on," says study author Paul Arciero, D.P.E., a professor of health and exercise sciences at Skidmore.
After the first couple of weeks, they were happy with a single cheat meal or an occasional dessert rather than a full day without rules. Although it was impossible to say whether the call to cheat was crucial to the participants' success, Arciero was intrigued; he decided to follow up with several longer-term studies. What he's finding could lead to new and less militant weight-loss strategies. Answer these questions and outsmart the flab monster.