Fad Diets: Revisiting Fad Diets of the Past (cont.)

And the list goes on and on and on ? the raw food diet, the macrobiotic diet, the vinegar apple cider diet, the breathing diet ?You name it and it's conceivable that there has been a diet based on consuming it and/or avoiding it.

The Changing Face of Weight Loss

"If you really look at these plans, they were all typically very low in calorie -- almost starvation-based," Kulze tells WebMD. "There has been an advancement in science of nutrition and weight loss and a lot of older fad diets are at odds with that information," she explains. Today, "people are approaching weight loss from a different perspective," Kulze says.

Thirty years ago, weight loss was about appearance and aesthetics. Now "the message is out about the impact that [weight loss] has on your health and we have so much wonderful information on how certain foods can promote health," she says. "Permanent weight loss results from permanent diet and lifestyle changes, so the trend has been away from fad diets."

Not to mention the fact that these fad diets are difficult to adhere to, she says. "They take a lot of planning, you have to buy all your own food and you can't go out to eat," she says. "We are really into convenience; we like to go out to eat and these diets took major planning," she says.

Are Carbs the New Calorie?

"With the exception of the macrobiotic diet, which is more philosophical and body cleansing, many of the fad diets of the past were based on caloric restriction," says Geri Brewster, RD, MPH, a nutritionist in New York City and Westchester, N.Y., and the former director of nutrition at the Atkins Center for Complementary Medicine. "We have gone from calorie content to looking at macronutrients," she says.

Broadly, Brewster points out, diets of past were based on calorie control and now we are looking at the type of calorie.

Decades ago, "I really think [fad diets] were popular because for the first time, medical doctors were writing these books," she says. But "there was no magic bullet; they were calorie-control diets."

As time wore on, people grew savvier, more scientific, and started attacking nutrients.

"Diets that were too calorically restrictive are not sustainable long term and were easily replaced by the notion that you could eat more of something," she says. "We removed the fat and that, of course, is incorrect so now it's eliminate the carbohydrates and sugar and go back to protein," she says.

Her hope long term is that the pendulum will swing back into some semblance of normalcy and diets will mainly comprise lean protein, good fats, and complex carbohydrates.

Where Are They Now?

"I haven't seen the Scarsdale diet, cabbage soup diet, or the Beverly Hills diet in a long time," says Samantha Heller, RD, a senior clinical nutrition at the New York University Medical Center in New York City.

"One of the reasons that they have fallen by the wayside is that they are very calorically restrictive and they all say don't stay on them for more than seven to 14 days," Heller says.