After her first daughter, 51-year-old Debbie Bakeman of Burbank said she packed on the pounds, eventually weighing more than 200 pounds.
She went to a weight loss clinic and tried a low calorie diet plan which included injections of the pregnancy hormone called human chorionic gonadotropin, or HCG.
"Basically, within a few months, I had great results," Bakeman said.
In about two to three months, Bakeman lost 40 pounds.
Using HCG, Dr. Lorraine Maita has helped many of her patients at her New Jersey practice lose large amounts of weight within 26 to 40 days. She's tried it herself and lost 12 pounds.
The diet's creator, Dr. A.T.W. Simeons observed starving women in third-world countries deliver healthy babies. He determined the hormone helped these women transfer fat stores in order to nourish their babies.
"That's how he determined HCG will mobilize body fat," Maita said.
During pregnancy, a woman's body produces about 300,000 international units (IUs) of HCG. On most HCG diets, patients are given about150 IU's.
But in order to get your body to burn its fat stores, the other part of the diet is severe calorie restriction, a mere 500 calories per day. Some say that's the real reason the diet works. Other critics say the evidence shows HCG is no better than a placebo.
Huntington Hospital's Dr. John de Beixedon says people lose weight because they're hardly eating, which can lead to malnourishment.
"I have to go with the science on that one," Beixedon said. "So far, there is really no proof and benefit to HCG."
Another concern is that HCG diets are marketed using homeopathic supplements, liquids and tablets that dissolve under your tongue. Most doctors say the diet's only safe and effective using the injected form, done under a doctor's supervision.
"What's dangerous about it is that people are buying things from the Internet, they're unmonitored, they're not being supervised by a physician," Maita said.
Dr. Mehmet Oz, who was interviewed several HCG experts on his show, said he'd like to see more research.
"I've asked some of these doctors to do trials, to actually use it in a few dozen people and then give me the raw data," Dr. Oz said. "Let me understand because I've been getting some of this information. I really am curious. There's something happening with the HCG diets."
Maita said the rapid weight loss plan is simply a tool to get people to their desired weight. The real challenge is keeping it off.
After the HCG diet, Bakeman said she gained even more weight. The only thing she really lost is money. The diet is costly, about $1,000 for 26 days. Follow-up costs vary after that.
HCG hasn't been approved by the U.S. Food and Drug Administration as a treatment for weight loss, and there aren't any long-term scientific studies about its safety.