Restrictive diets are hard to stick with, especially when you must eliminate most of your favorite foods.

Research has also found that cutting out a particular food can cause cravings and may lead to overindulgence -- and weight regain -- when you allow yourself to enjoy it again.

Since permanent weight loss really involves a forever approach, learning how to work in your favorites, especially sweets, is a must even during the weight-loss phase.

Penn State University researchers set out to test whether purposefully including a favorite snack in a diet could help people stick with their eating plan and achieve weight loss success. They conducted a small study in which all the participants followed a low-calorie, high-nutrient diet of whole grains, vegetables, fruits, non-fat milk and lean protein with a small number of daily calories going to a sweet treat.

For one group of participants the treat was one small square of chocolate twice a day plus a sugar-free cocoa drink. For the other group, the treat was red licorice, plus the cocoa drink.

After 18 weeks, both groups lost inches and pounds, with the chocolate group achieving slightly better results. The researchers also found that participants didn't overindulge in their treats -- they kept within the overall calorie-range of their diet -- and that the snacks kept cravings under control.

To try this approach on your own, you must practice portion control. Make sure most of your intake is from nutrient-rich foods. And allot no more than 150 calories a day to your preferred snack -- that's about one ounce of dark chocolate.