By Maggie Fox, Health and Science Correspondent

WASHINGTON (Reuters) - A nutrition advocacy group said on Thursday the popular Atkins diet has caused heart disease and could have killed a teen-age dieter and urged the U.S. government to monitor the high-fat weight loss approach.

The Physician's Committee for Responsible Medicine stressed it could not prove the diet hurt or killed anyone, but one dieter said he was convinced the approach clogged his arteries and the parents of a teen-ager who died while on the diet also blame her meat-heavy regimen.

The PCRM called on the U.S. Centers for Disease Control and Prevention (news - web sites) to monitor diet approaches and check for evidence that the Atkins and other high-fat, high-protein diets may be harming people's health.

"You can never say this diet caused this death," PCRM director Dr. Neal Barnard cautioned. That is why he said the CDC should monitor large groups over time to see if there is an association.

The CDC had no immediate comment.

But Atkins Nutritionals, Inc. said its diet was safe. "There is no logic and no science to support any association between these individuals and the ANA (Atkins Nutritional Approach)," said Colette Heimowitz, vice president of education and research for the company.

The Atkins diet has made headlines around the world with a radical approach that flies in the face of most medical advice. First published in 1972 by Dr. Robert Atkins, who died after a fall last April, it is based on the theory that carbohydrates make people fat.

It encourages dieters to shun bread, pasta, fruit and many vegetables in favor of meat, butter and other fatty food.

"What I contend is that the Atkins diet gave me heart disease," Jody Gorran, a 53-year-old Florida businessman, said at a news conference. He said his arteries clogged and cholesterol shot up while on the diet.

DEATH OF TEEN DIETER

Paul and Lisa Huskey of Columbia, Missouri, say their 16-year-old daughter, Rachel, died of a heart arrhythmia in 2000 while on the diet. Dr. Paul Robinson, a pediatrician at the hospital where Rachel died, said the diet could have caused her death by leaching calcium and potassium from her body.

Many doctors and the American Heart Association (news - web sites) have warned that the diet could be dangerous. The Heart Association advocates a diet based on whole grains, fruits and vegetables.

It warned that over time the Atkins diet and similar approaches could raise cholesterol. Other experts have said it might also increase the risk of kidney disease and the PCRM adds osteoporosis and colon cancer to the list of risks.

The PCRM, which advocates a strict vegetarian diet, set up an online registry at www.atkinsdietalert.org for people to offer complaints about the diet.

Barnard said 188 people had logged on and complained of minor issues such as bad breath, constipation and a lack of energy. But then the complaints became more serious and included kidney, heart and gallbladder problems.

"These are all the conditions that physicians warned would be likely to occur in individuals on low-carbohydrate, high-protein, high-fat diets," Barnard said.

Doctors say anyone who loses weight will lower cholesterol in the short term.

More than 60 percent of American adults ore overweight or obese so the need for effective diets is clear.

"The skinniest people on the planet are vegetarians and Asians," Barnard said.