The secret to losing weight, Sanford Siegal has been telling his patients more than 30 years, is eating cookies.

From his kitchen in Kendall, he baked up a 90-calorie concoction that is rich in hunger-suppressing amino acids and kneaded it in cookie dough. He vowed they could lose between 10 and 15 pounds in a month by eating six a day -- and a reasonable dinner.

After decades of refusing the national spotlight, the 80-year-old doctor has gone commercial. He's taking trips to Beverly Hills and catching up with the Kardashians. He's feuded with Madonna and done media blitzes on shows that don't really cater to his demographic.

``I'm flying to L.A. to do a segment for this show called Extra,'' Siegal said recently. ``It's one of those flashy shows.''

To those people, he is simply The Cookie Man. Although this moniker has given him wealth and prestige, he often wants people to remember that ``doctor'' is the title he is most proud of.

Siegal began his medical practice in Hialeah in the pre-Slim Fast world of the 1950s, and soon noticed most of his clients wanted advice on how to lose weight. So he began focusing on obesity, drawing the conclusion that simply encouraging exercise and healthy eating would not be realistic. If clients wanted to eat, they would.

``Hunger kills diets,'' is one of Siegal's favorite phrases.

He started experimenting with different protein-based ingredients to make a person feel full. Then he threw in a little flour, a little sugar and created the cookie. Because the cookie satisfies the eating sensation, Siegal said, the person takes in fewer calories -- 1,000 in a day -- and feels like they are eating much more.

After the person reaches an ideal weight, Siegal then suggests exercising to keep the pounds off. At this point, Siegal says it's easier to persuade someone to exercise because there's an incentive to keep the pounds off.

Siegal is no Mrs. Fields or Famous Amos. Still, as results came in, his popularity ballooned locally.

In the 1990s, he had 13 offices in Miami-Dade and Broward. He estimates more than 500,000 people across the country and Latin America have used the cookie diet.

The cookies, made inside a tiny Kendall warehouse with two dozen local workers, are now a multimillion-dollar business, according to his business manager -- who happens to be his son.

In 2007, Matthew had an idea for his father. Given all his success locally, Matthew thought his cookies could be the next big thing. Websites! Retail! Press appearances!

No, his father told him.

``I grew up with the idea that doctors are supposed to be distinguished,'' Sanford Siegal said. ``We weren't supposed to be out on television. I guess the world has changed.''

His son had another view. ``I told him, `In order for this to be very successful, I've got to turn you into a celebrity,'' Matthew said. ``And boy, did he cringe at that . . . My father has always hated self-promotion.''

Still, Matthew pressed on. He persuaded his father that, nowadays, the best doctors need to brand themselves. The public had begun to be saturated with all sort of diets: South Beach, Scarsdale, Atkins, Weight Watchers, Jenny Craig, high-carb, low-calorie, only grapefruits, only cabbage.

Matthew, a marketer who lives in the D.C. suburbs, crafted the business strategy. They launched the site at cookiediet.com. They put booths in Dadeland and the Galleria Mall. A lot of Web traffic came from Los Angeles, so they set up another store along Rodeo Drive.

Soon, Madonna was complaining that her then-husband, Guy Ritchie, lost his sex drive because of the cookies -- a claim Siegal disputes. In January 2009, one of Siegal's clients was featured on the cover of People Magazine for losing half her weight.

Siegal blushes when discussing celebrity clients, whom he still regards as his ``patients.'' The tabloids haven't been as conscientious, citing Jessica Simpson, Kelly Clarkson and Denise Richards as women who have taken on the diet.

The protein-rich ingredients are churned and pulled together by Siegal and his wife in their basement, as always. Siegal takes the secret mixture to the warehouse in 55-gallon tubs, where workers stir, pour, bake and pack the cookies. They come in oatmeal raisin, chocolate, banana, coconut and blueberry.

The reviews aren't always positive. In 2008, CBS' Early Show had a taste test of the many cookie diets, in which a dietitian stressed that it's always better to eat real food. Host Maggie Rodriguez tried one of Siegal's cookies and said, ``I have to admit, it doesn't taste that great.''

Still, Siegal has more than 600 re-sellers across the nation and celebrities clamoring for another bite. And the list is growing. This month, Siegal's cookies debuted at Aventura Mall.

``Honestly, I wouldn't be hurt if this is all just a fad,'' Siegal said. ``My goal was to help people lose weight and we've succeeded . . . But if we've been doing it for 34 years, it can't be a fad.''