You have plenty of company. The number of obese Americans has risen from 13 percent in 1960 to 22.5 percent today. Two out of three adults are trying to lose weight, according to the Journal of the American Medical Association.

There's enough dieting advice out there to fill a dozen refrigerators, yet millions of Americans still find it tough to take off what they put on so easily. Why is it so difficult to lose weight and keep it off?

Boring but sensible

The collective failure to slice off the pounds probably has less to do with lack of will power than with the stubborn refusal to accept the boring truth, writes Carol Rinzler. Unfortunately, the only way to lose weight and keep it off is to follow a sensible weight loss diet to produce a trimmer, healthier, probably happier you and stay that way through a life-long pattern of healthful eating and regular exercise.

Losing weight isn't just a matter of looking good but of staying healthy. Carrying around extra pounds puts you at risk for developing many diseases, especially heart disease, stroke, diabetes and cancer.

Rinzler weighs in with the experts when it comes to theories about the best way to slim down: gradually. According to the National Institute of Diabetes and Digestive and Kidney Diseases, no matter how much weight you have to lose, modest goals and a slow course will increase your chances of both losing the weight and keeping it off. You should expect to lose about a pound a week after the first week or two.

The little things theory

The slow-but-steady philosophy is behind what Rinzler calls her Little Things Theory of Dieting. The idea is to maintain slow but steady weight loss by cutting calories in amounts so small that you won't even notice they're gone.

I like the 'Little Things Theory,' and I would like to stress that losing weight doesn't have to be torture, Rinzler says. It's designed to show how you can live the rest of your life without giving up everything you love (to eat).

To lose weight, you have to cut calories. Basically, a pound of fat is equivalent to 3,500 calories. If you regularly consume about 2,000 calories a day, you would have to shave off 500 calories a day to take off one pound in a week.

Dieters often want instant gratification. They want to lose a lot of weight in a very short time, Rinzler says. So, they choose something impossible like eating nothing but lettuce leaves. In short order, they fall off their draconian diet and reward themselves with a fat pastrami sandwich.

Using the Little Things Theory, Rinzler says you don't think in hundreds of calories, you think in terms of ones or tens and make your weight-loss program a one-year plan. For example:

One teaspoon of sugar is worth 16 calories. If you put sugar in your coffee and if you drink three cups a day, that's 48 calories. Switching to a no-cal sugar substitute saves 48 calories a day. Multiply that by 365, and you save 17,520 calories a year. At 3,500 calories a pound, that's five pounds less of you, just by giving up three teaspoons of sugar a day.
One slice of bread is worth 90 calories. Make your lunchtime sandwich with one slice of bread rather than the customary two, and you save 90 calories a day or 32,850 calories a year for a net loss of nine pounds of body fat.
One 12-ounce can of regular soda a day equals 150 calories. One 12-ounce can of diet soda doesn't have any calories. Switching to the diet brand saves 54,750 calories a year and peels off 15 pounds.
You won't turn skinny overnight, Rinzler says, but you will lose steadily without feeling deprived and without depriving your body of much-needed nutrients. The Little Things Theory is also more likely to provide lasting results.

Examining diet fads

According to the National Heart, Lung, and Blood Institute, weight-loss methods that rely on fad diets and diet aids such as drinks, prepackaged foods or diet pills don't work in the long run.

Diets that prohibit or severely restrict whole food groups are also dicey, Rinzler says. One-food diets? No way, she says. They lead inevitably to boredom and some kind of nutritional deficiency, she says.

Low-carb, high-protein weight loss plans such as Dr.Atkins' New Diet Revolution, The Carbohydrate Addict's Diet, Protein Power, and Sugar Busters, may take credit for helping people to drop weight quickly, but critics contend that most of the initial weight is water. So in most cases, these diets do not help people keep weight off once they go off the program. Further, they prohibit or severely restrict consumption of whole categories of foods, such as grains, cereals, vegetables and fruit.

Furthermore, low-carb, high-protein diets emphasize foods from animals, which means you get more total fat, more saturated fat, and more cholesterol each day, a combination that may raise your risk of cardiovascular disease, Rinzler says. Of course, being obese also raises your risk of cardiovascular disease, but Rinzler says the point is there are healthier ways to lose weight.

Finally, you should know that any sensible weight-control plan includes exercise. Exercise not only helps to burn calories, but it builds muscles and lowers blood pressure.

According to experts, the number one predictor for long-term weight control is exercise.