Diet Season is upon us, that early stretch of January when anyone with drinker's remorse over a punchbowl of eggnog scrambles for a fast and easy way to drop extra pounds.

And in Sanford Siegal's opinion, weight-loss success depends on one smart cookie.

Some will turn to meal-replacement plans such as Dr. Siegal's best-selling "Cookie Diet," which, despite its longevity, is still considered one of this year's "hot" weight-loss strategies.

Dr. Siegal, a Pittsburgh native who began marketing his cookies in 1975, figures he has helped more than half a million people lose weight through a plan that has been copied ("The Hollywood Cookie Diet," "Smart for Life Cookie Diet") numerous times.

The secret, according to the product's Web site, www.cookiediet.com, is a "proprietary amino acid mixture that results from the blending of various protein food substances."

Every week, Dr. Siegal and his wife, Lyndol whip up this mixture; they are the only ones with the recipe. Some day their son, Matthew, CEO of the company, will inherit it.

"I just mix the formula, I don't bake the cookies," Dr. Siegal said. Indeed, the cookies are produced at two South Florida bakeries near Miami, where he has had his medical practice since 1957.

Here's how the diet works: Each day, you consume six of Dr. Siegal's pre-packaged, appetite-suppressing cookies, then have a "sensible," 500-calorie dinner of lean protein and vegetables. Participants are encouraged to take a multivitamin supplement daily and drink lots of water.

Cost is roughly $59 per week if purchased through the diet Web site, roughly $4.20 per "meal."

The math of it is simple: almost anyone consuming under 1,000 calories a day is going to lose weight, but the question is, is it a safe or even practical long-term approach?

Madelyn Fernstrom, director of the Weight Management Center at the University of Pittsburgh Medical Center, said that cookie diets and their ilk are nothing novel: "Remember Metrecal?"

That 1960s diet phenomenon was a powder you added to milk for a "shake" or bought pre-mixed, in cans. It was meant to replace at least one meal a day and was marketed specifically with women in mind.

"Metrecal was mentally helpful, that's all it was. Same with these cookies and their 'proprietary information,' the 'secret' hunger suppressant.

"Taking it to its most ridiculous conclusion, any time you eat a meal when you're hungry, it's a natural hunger suppressant," said Dr. Fernstrom, author of the recently released book, "The Real You Diet."

"I am constantly criticized by 'experts' who say 'no, that rapid weight loss is dangerous,' " Dr. Siegal said. "To which I always respond: What makes it dangerous?' "

Dietary supplements are not regulated by the U.S. Food and Drug Administration. Unless enough known cases of illness or even death are reported -- as in the case of ephedra, banned in this country in 2004 after it was linked to strokes, heart attacks and at least two dozen deaths in the 1990s -- manufacturers are pretty much free to market unknown substances.

"At the very least, it [supplements] is a waste of money. At worst, it can harm you," Dr. Fernstrom said.

Carol Kolb of Ross said she was skeptical before trying Dr. Siegal's diet, but is now a believer.

"This sounded too good to be true, so I ordered just one week [of cookies], plus the book," said Mrs. Kolb, a retired benefits representative for U.S. Steel who lost 20 pounds in two months. "I tried the cookies one day and thought 'They can't be this good,' but they were, and I right away went out and ordered another month's worth.

Mrs. Kolb, 55, stands 5 feet, 2 inches. She said she's always been in fairly good shape and enjoys working out. Still, she had yo-yo'd through various diets and was what she considered 10 pounds overweight. The death of her mother led to stress eating last March and she put on an additional 10 pounds in a short time.

Dr. Siegal's plan strongly recommends foregoing strenuous exercise until goal weight loss is achieved. After that, working out helps maintain the desired weight as more traditional foods are reintroduced into one's diet.

Mrs. Kolb, who years earlier had tried the Atkins Diet (low carbohydrate) with little success, said going back to the gym has helped her maintain her weight, although she would like to eventually reach 122 pounds.

"When you see this weight coming off right in the first month, really easy, it seems like 'Oh, my goodness,' " Mrs. Kolb said.

It's precisely that response that makes his diet so successful," said Dr. Siegal, who used these cookies in his practice back in the 1960s and began marketing them almost 35 years ago.

"The slow, steady method [of weight loss] sounds good, sounds healthy. It's also the recipe for failure because that's what makes people give up the diet," he said. "I had been treating obesity in my practice for several years before it struck me: losing weight slowly is discouraging. It's why I developed this product."

Philip Miele is an accountant who lives in Langhorne, Bucks County. Tall and athletic, he was dismayed but not surprised when his weight began to creep.

"As you can imagine, in my job I'm pretty well nailed to a desk. Food is always around," said Mr. Miele who dropped from 240 to around 190 pounds after four months on the cookie diet.

"Really, I was surprised. I had been skeptical because I tried other things like the South Beach diet [restricts some carbs, promotes some fats] and had had some success. But this gives you cookies, sort of the carbohydrates you crave."

"In order to lose weight, you have to be motivated. Under the best of circumstances, it's not easy ... you have to be able to control the hunger in the individual," Dr. Siegal said.

"And if you expect magic, it just doesn't happen that way."

"People are always interested in 'what's next? what's next? what's next?' and from a marketing concept, the cookie diet sounds very enticing," said Imperial's Heather Mangieri, president-elect of the Pittsburgh Dietetic Association.

"And it is simple and convenient and people are always looking for those kinds of diets. ... but the biggest thing is, most individuals on these will get bored. They need to incorporate [real] foods back into their lives and at the end of the day, they never learn how to do this properly."

"People often choose popular diets because they promise quick weight loss," said Joanne Larsen, a registered dietitian from Chicago who edits the American Dietetic Association's online diet manual at www.dietitian.com. "This seems to work for about three weeks until people fall off the diet wagon because either the calorie level is too low -- hunger -- or too many foods are eliminated -- no variety, boredom...

"Usually when a person goes back to their usual eating habits, irrelative of how much weight they have lost, weight is re-gained and typically more weight than the person had to lose in the first place," Ms. Larsen said.

Dr. Fernstrom noted that in the end, a cookie is just a cookie, and not the basis for nutrition: "You could just as easily eat three bowls of Special K every day. I think people are ready for a little complexity."

This version corrects Heather Mangieri's position.

First Published: December 28, 2009, 10:00 a.m.