It's no secret that Americans are fat -- and getting fatter by the burger. Nearly one-third of U.S. adults are overweight, and another third are technically obese, as defined by a body-mass index of more than 30. And Americans aren't happy about it. Last year, we spent an estimated $46 billion on diet products and self-help books.
Much of that money is wasted. Indeed, a government review found that two-thirds of American dieters regained all the weight they had lost within a year, and 97 percent had gained it all back within five years. And following these regimes is significantly more expensive than the tried and true technique of eating less and exercising more.
How much more? To find out, we examined weekly menus -- culled from official publications or company representatives -- from ten of the most popular diets on the market: Atkins, Jenny Craig, Ornish, NutriSystem, Slim Fast, South Beach, Subway, Sugar Busters!, Weight Watchers and Zone.
The median diet worked out to a costly $85.79 a week -- that's 50 percent more than the $54.44 the average single American spends on food. Our price calculations for the foods on each menu were done on a per-serving basis. Prices came from New York City-based online grocer Fresh Direct and were adjusted to the national average to control for any price differential.
Jenny Craig dieters were the hardest hit. A week's worth of food, which included both Jenny Craig-supplied meals and supplemental snacks, cost $137.65. Jared Fogle's informal -- but, for him, effective -- Subway Sandwich Diet was the least expensive of the bunch at $68.60 a week. The Sugar Busters! Diet came in a close second, with its weekly menu costing $69.62.
Does it really cost more to eat healthfully?
It doesn't have to, according to Dr. Pamela Peeke, a Pew Foundation scholar in nutrition and metabolism, "as long as you keep it simple." A typical, unfussy Sugar Busters! dinner of baked turkey breast with vegetables and a sweet potato on the side worked out to a mere $3.24. By contrast, one Ornish dinner had a shopping list 28 items long--and that's not counting herbs, spices or condiments. And an Atkins lobster salad lunch recipe called for one-quarter pound of lobster tail meat at $25.99 a pound.
"How many people know what orange roughly is? Give me a break," Dr. Peeke grumbles. "Give me a skinless, boneless chicken breast and call it a day."
And despite the extra cost, most diets currently on the market are not effective. "Let's face it," says Dr. Stephen Gullo, a New York City doctor and author of The Thin Commandments Diet, "this is the only growth industry in the United States where most of the customers fail."
"The very existence of the diet industry is proof of its ineffectiveness. If there were one safe, effective way to lose weight, then the others would be out of business," says Marilyn Wann, author of Fat! So?
According to Ernst Schaefer, a professor at Tufts University, "The fundamental misconception about diets is that most people are looking for a magic bullet." He--and many other nutritionists--claim that the most effective way of losing weight is to restrict caloric intake, and the most effective way to maintain the loss is through regular exercise.
Marian Nestle, professor of nutrition at New York University, agrees. "Eat less, move more," she suggests.
© 2012 Forbes.com