I don't know about you, but even though I love every sunny, poolside moment of summer, I secretly rejoice when the days start to get shorter and the air a little chillier. The end of summer means the beginning of fall, and that means I get to drop kick my bathing suit and body-baring shorts and tanktops. I don't have to be so conscious of what I'm eating. And not eating.

But "dieting" isn't a seasonal activity. People watch what they eat year-round. According to Forbes, "Americans spent an estimated $46 billion on diet products and self-help books in 2004." If that's the case, why is obesity such a problem in the US? Because, as a government review has found, two-thirds of dieters on "diet regimes" will regain all the weight that they lost within a year. Give them five years, and almost everyone will gain it back.

People gain the weight back for a number of reasons, but one of them is that the popular diet programs are very expensive, especially since many health and nutrition experts believe that they are ineffective to begin with. Forbes examined the weekly menus of the ten most popular diets to find out just how expensive they really are. The results are listed below. The first dollar amount is how much the program costs per week for any associated book, membership fees, and food costs, and the second percentage is how much more that is than the average $55.44 a normal person spends on food.

• Jenny Craig - $137.65, 152.8%
• NutriSytem - $113.52, 108.5%
• Atkins - $100.52, 84.6%
• Weight Watchers - $96.64, 77.5%
• Zone Diet - $92.84, 70.5%
• Ornish - $78.75, 44.6%
• South Beach - $78.76, 44.4%
• SlimFast - $77.73, 42.8%
• Sugar Busters - $69.62, 27.9%
• Subway - $68.80, 26%

Whatever happened to good old fashioned "eat less, exercise more?" I think that's free.

The Wall Street Journal recently featured a story about how companies like Unilever, Danone and Kraft Foods are trying to create unique food ingredients that will help dieters stave off hunger. Unilever, maker of SlimFast, is working with something called the "ileal brake mechanism," a response from the small intestine telling the brain that the eater's body is sated. By creating fat molecules that can pass through the body and still trigger the response, products like SlimFast shakes would leave people feeling full for longer. Similarly, Danone is working on starches that break down slower in the digestive system, thereby keeping blood sugar levels up for longer periods of time. Still, experts in the article point out that hunger comes from many sources and and that satiety (fullness) is not something that can be achieved reliably with one single ingredient.