First, the good news: They work. The Nutri/Systems, the Jenny Craigs, the Optifasts, the Weight Watchers and all the rest of the parade of mass-market, enrollment-style diets currently on the American scene. Sign up, stick with it and lose weight. If you're faithful, it's virtually guaranteed.
More good news: They're not considered dangerous. Stay within the doctor's guidelines and the diet's strictures and you'll likely stay healthy.
The inevitable catch: The real world. Real meals. Real food. Actual day-to-day eating without diet counselors, group support, weekly meetings, prepackaged foods or strictly limited calorie intake. Going it on your own in the world of restaurants and dinner parties and seemingly limitless food choices.
"These diets all have some really positive points about them," says Bettye Nowlin, a registered dietitian and a spokesperson for the American Dietetic Assn. "They all use behavior modification and all have an exercise component, and you need both of those to be successful. But they're not realistic in the long term. People aren't going to keep up these systems all their lives."
Still, say medical and diet professionals, the current crop of diet plans, many of which have appeared only in the past decade, are far superior to their gimmicky or ill-advised antecedents that emphasize practices such as food combining, single-food diets, fasting and other questionable weight-loss strategies. The newer diets, which shun such oddities and often recommend or require close medical supervision and sound, basic nutrition, have little relation to fad diets such as the nutrient-deficient Last Chance Diet that was briefly popular in the 1970s and was blamed for several deaths.
But the new diets are playing for high stakes--the enrollment-style diets are estimated to be a multibillion-dollar industry--and each offers a distinctive "hook" to attract the approximately 100 million overweight Americans. The maxim of the diet biz in the late 1980s remains: You gotta have a gimmick.
The enrollment-style diets fall into three basic types:
Liquid, or supplemented fast, diets. These plans typically are medically supervised, either by the dieter's personal physician or one designated by the diet facility. The regimen involves an initial period of abstaining from solid food and subsisting on the low-calorie, high-nutrient liquid supplement. A normal, balanced diet is then gradually reintroduced during a period of counseling and behavior modification. Optifast and the Cambridge Plan are typical examples.
Prepackaged food diets. Dieters are provided with full menus of prepackaged, low-calorie foods that they prepare themselves. There are periodic group meetings and behavior modification classes with diet counselors. The Nutri/System and Jenny Craig plans belong to this category.
Low-calorie, "real food" diets. Participants attend meetings, behavior modification classes and group support sessions while adhering to a specified, varied low-calorie diet incorporating foods available at a grocery store. Diet Center and Weight Watchers are examples.
All the diets, however, have one thing in common: claims of long-term success. The responses of medical and diet professionals to those claims is equally consistent. They say that, in most cases, they aren't true.
"(The diets) are, I think, fairly successful in the short run," says Albert Marston, a professor of psychology at USC who specializes in the study of diet and weight control. "All diets see good weight loss at the beginning. The first problem people face is the loss of motivation after several weeks. They get bored with the food or frustrated with not eating. The really big problem is getting people all the way down to their goal weight."
Marston says studies he has conducted have shown that dieters reaching their goal weight "have a far better chance of keeping the weight off. If they drop out before that, the tendency is to gain (the weight) back."
(Claims by the diet plans notwithstanding, independent medical and nutrition experts interviewed say 90% or more of dieters are likely eventually to gain all or a portion of their lost weight back.)
For those who do reach their goal weight, says Marston, other pitfalls lurk. While all the enrollment-style diets emphasize behavior modification and counseling in proper nutrition and the psychology of eating, "they try to get people to come back for maintenance (programs), but once people leave the diet they tend to think of it as history," Marston says. "Attendance at follow-up meetings is generally very poor, and that's a time when people need to be very careful. Because when they slip, the attitude tends to be, 'Oh, I've blown it.' They have a kind of fall-off-the-wagon attitude."
Dieters are less likely to suffer that slip if good eating habits are emphasized from the very beginning of a diet, says Ann Coulston, a research dietitian at Stanford University Medical Center.