Has your belt moved a notch when you weren't looking? Have all your clothes suddenly "shrunk?" Are you 10-15 pounds heavier than you'd like to be?

You're not alone if this describes you – and like many Americans anxious to look their best, you are probably desperate to try just about anything to shrink your waistline – fast.

Here is the bad news. There are a lot of fad diets in circulation that promise rapid weight loss, frequently by overemphasizing one particular food or type of food. Sometimes these unhealthy diets are even rumored to come from the American Heart Association. For example, last year a "cabbage soup" diet, which recommended a very limited menu, was erroneously promoted as being endorsed by the association.

"Many fad diets, like the cabbage soup diet, take advantage of people's desire for instant results by creating the myth that certain foods – in this case cabbage - have magical weight loss properties," says Robert H. Eckel, M.D., a member of the American Heart Association's Nutrition Committee and professor of medicine and physiology at the University of Colorado Health Sciences Center in Denver.

"Diets that overemphasize one particular food or food group are usually grossly unbalanced nutritionally and leave out a major component of any weight loss or maintenance plan, which is exercise." says Dr. Eckel.

"In addition, people who stay on a very limited diet can develop nutritional deficiencies, because no one type of food has all the nutrients necessary for good health.

"Starting and maintaining physical activities, like walking briskly 30 minutes a day most days of the week, is very useful for both losing and maintaining weight.

"Those able to withstand the monotony and boredom of a fad diet for more than a few weeks may lose weight, but for how long?" adds Dr. Eckel. "Most people eventually return to their old eating habits, which were responsible for their weight gain in the first place."

"Changing your eating pattern is easy for a short time, but maintaining it and overcoming the obstacles is harder. Successful dieters prepare themselves by setting clear goals, anticipating roadblocks they'll encounter, and deciding beforehand how they'll deal with challenges. They're also committed to modifying their usual way of eating. Becoming overweight doesn't happen overnight, neither does losing weight and maintaining weight loss," says Dr. Eckel.

Here's the good news. Recently the American Heart Association issued revised dietary guidelines that emphasize flexibility in food selection. Although the organization still recommends keeping total consumption of fats to no more than 30 percent of a total diet, the new guidelines suggest that people consider their diet over the course of the week, instead of one day. This allows some flexibility in choosing foods and fits the theme of consuming a variety of foods and reducing guilt from eating something high in fat now and then.