A long-ago discredited fad diet has been getting increased attention lately, thanks to Web chatter and the claims of a bestselling author. The so-called HCG diet's recent popularity is a bit surprising -- and not just because research suggests it doesn't work.
Other currently popular diets call for cutting back on fat and sugar, consuming whole grains and lean meats, and even indulging in red wine. The HCG diet, in contrast, calls for eating just 500 calories a day while taking daily injections of human chorionic gonadotropin (HCG), a hormone produced by the placenta during pregnancy and excreted in pregnant women's urine.
According to the hype, HCG suppresses the appetite and prevents dieters from feeling weak or woozy on the low-calorie diet. But as with any fad diet, consumers should be wary of such claims, says Kelly Brownell, professor of psychology, epidemiology and public health at Yale University in New Haven, Conn.
The idea that daily hormone injections might help people lose weight first occurred to British physician A.T.W. Simeons in the 1930s. At the time, doctors had reported success treating children with Frohlich's syndrome (a condition marked by obesity and slow development of the reproductive organs) by giving them injections of gonadotropin derived from pregnant women's urine.
Simeons decided to experiment with giving the gonadotropin (it would later come to be called HCG) to people who were obese but did not have Frohlich's syndrome. When he did so, his patients' appetites diminished and the circumference of their hips and waists decreased -- even though they did not lose weight.
Simeons interpreted those findings to mean that the hormone moved fat away from the places where it was traditionally deposited and rendered it available for metabolism. He further supposed that if he injected overweight people with the hormone while limiting them to no more than 500 calories a day, they would metabolize that newly available fat and lose weight in the process.
Over the next 20 years, Simeons placed 500 of his patients on a strict weight-loss regimen: a daily shot of HCG and two daily meals consisting of 100 grams of lean meat, some leafy vegetables, fruit and a piece of crispbread, for a total of no more than 500 calories a day.
In 1954, he reported in the medical journal the Lancet that patients who followed the regimen for 40 days lost 20 to 30 pounds, and that 70% of them maintained their weight loss after going off the diet. He credited the hormone with making fat available for metabolism and enabling his patients to remain on the low-calorie diet without feeling weak, dizzy or excessively hungry.
Over the next few years, doctors who put their own patients on Simeons' regimen reported similar successes. But when doctors and researchers began to rigorously compare the diet's key ingredient -- HCG injections -- to a placebo, or dummy injection, they failed to produce evidence that the hormone was anything special.
In 1959, researchers in Israel reported that they had placed 45 patients on Simeons' diet, giving half the patients HCG injections and the other half saline injections. The two groups both lost weight at the same rate -- and all 45 participants complained of being constipated, hungry or weak.
In the early 1960s, researchers at UC San Francisco and at a U.S. Army Hospital in Fort Carson, Colo., came up with the same results. All three studies were published in the American Journal of Clinical Nutrition.
In the decades that followed, researchers continued to study the diet and to show that the hormone added little to the low-calorie regimen. In 1995, Dutch researchers reviewed the results of the 24 studies that had been conducted on the HCG diet.
Just 12 of them were well-designed, the scientists found; of those, 11 reported that HCG was ineffective in treating obesity. The Dutch team published its results in the British Journal of Clinical Pharmacology.
Despite these decades of negative study findings, the HCG diet was given new life by bestselling author Kevin Trudeau's 2007 book, "The Weight Loss Cure 'They' Don't Want You to Know About." Giving credit to Simeons, Trudeau recommended a multi-phase approach to weight loss, including a phase of daily HCG injections.
Trudeau has previously been targeted by the Federal Trade Commission for allegedly promoting unproven cancer cures, pain relievers and other products, and in 2004 was banned by the commission from appearing in infomercials selling products or services to the public. .
He said in a recent Chicago Tribune story that he wrote his latest book simply as a public service.
Regardless, the HCG diet continues to draw followers, with more and more online companies promising to supply the injections. The shots can come at a significant cost: Online prices range from $30 to more than $600 for a month's supply. And they have side effects. Simeons noted that his female patients often became pregnant while on the shots, and today, in fact, HCG is approved by the Food and Drug Administration as a fertility treatment.
Brownell says that any trendy diet should give consumers pause.
"Research has not found fad diets to be safe, effective and permanent," he says. "Consumers should be highly skeptical as the default."