A diet fad from the 1970s that claims to help people lose about half a kilogram a day is again attracting a lot of attention and followers, despite the concerns of some doctors.

The diet involves either injecting or ingesting the pregnancy hormone human chorionic gonadotropin, or hCG, in combination with an ultra low-calorie diet.

Proponents say the hormone suppresses the appetite by tricking the body into thinking it is pregnant, which prompts the body to burn stored fat in places where dieters least want it, such as the upper arms, belly and thighs.

Dianne Gariepy of Edmonton, who has taken hCG drops on and off since October, recommends it to anyone who wants to shed unwanted pounds without feeling hungry. Gariepy, who has diabetes, credits the hormone with helping her to lose weight, adding she now takes only a third as much insulin as she used to need.

Gariepy said her doctor supports the hCG diet. "When I walked in 40 pounds lighter into his office, he was thrilled," she recalled.

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Dianne Gariepy says she lost 40 pounds using hCG. (CBC)

The regimen combines hCG with a 500-calorie a day diet — the equivalent of two slices of lean turkey on whole wheat bread, one slice of cheese, some lettuce, a little mustard, an apple and one cup of skim milk.

Popular daytime TV shows, magazines and the internet are abuzz about the diet. Some doctors are prescribing hCG as an injection.

Risks of hCG

Health Canada is now cracking down on hCG weight-loss products. Some distributors says they can no longer get their products into Canada.

Dr. Tom Ransom, an endocrinologist at the Queen Elizabeth II Health Sciences Centre in Halifax, warns hCG has no benefit and carries risk.

"Any doctor who prescribes it for weight loss is either ignorant of weight loss and what hCG does or they're really slimy charlatans who are taking advantage of people's desperateness to lose weight," Ransom said.

Risks of hCG include headaches, depression, acne, hair loss, breast tenderness and, in more rare cases, blood clots that can be fatal if they travel to the lungs, Ransom said.

The U.S. Food and Drug Administration says hCG can also contribute to cardiovascular problems. Ransom said that's because the hormone can cause a slight increase in blood pressure and cholesterol.

The plan appears to be effective because of the accompanying starvation diet, experts said. Out of 14 trials that tested the plan, 12 found it had no weight-loss benefit.

With files from CBC's Pauline Dakin