Robert S. Beale Jr., a prominent diet doctor who treated thousands of people at his Washington weight-loss clinics, died Nov. 13 in a traffic accident in Gambrills, in Anne Arundel County. He was 62 and lived in Columbia.

Dr. Beale, a sports car enthusiast, was at the wheel of his 2004 Dodge Viper when it crossed the center line of Waugh Chapel Road and collided with a Cadillac Escalade driven by a woman from New Jersey, Anne Arundel police said. Dr. Beale was airlifted to Maryland Shock Trauma Center, where he died of his injuries, they said. No one else was seriously injured in the daytime accident, which remains under investigation.

Dr. Beale was considered a pioneer in bariatric medicine, or the specialty of treating obesity. He was known particularly for his work with black women. In 30 years as a weight-loss specialist, he saw more than 25,000 patients and claimed to have treated more black women for obesity than any other physician in the world.

His work won him legions of devoted followers, but his practice was not without problems. Several times, Dr. Beale found himself at odds with medical and legal authorities over accusations of fraud and sexual harassment.

This year, he published "The Black Diet Doctor's Solution for Black Women," written with his daughter, Lisa M. Beale. The premise of the book, and of Dr. Beale's practice in general, was that black women have special physiological, psychological and social needs that affect their ability to lose weight.

"Genetics loads the gun," Dr. Beale wrote on a Web site promoting his book, "environment pulls the trigger."

After beginning his career in Glenarden in 1971 as a family doctor, Dr. Beale noticed that many of his patients had diabetes, heart problems and other illnesses exacerbated by obesity. He decided to treat the source of his patients' ailments, his daughter said, and in 1974, began to specialize in bariatric medicine. In 1978, he opened a weight-loss clinic in Anacostia and, later, a second office in downtown Washington.

"If you went out on the streets of D.C. and asked women about weight loss," said Ronald H. Johnson, a bariatric physician practicing in Fredericksburg, "I don't think it would take long before someone mentioned the name of Dr. Robert Beale."

Robert Spencer Beale Jr. was born in Prairie View, Tex., grew up in Durham, N.C., and graduated from Phillips Academy in Andover, Mass. He received his undergraduate and medical degrees from Howard University.

In 1982, Dr. Beale, whose practice emphasized checkups at least once a week, came under investigation for collecting $744,000 in D.C. Medicaid payments in four years. In some years, he netted more than $200,000 in Medicaid when the typical D.C. physician took in $12,000. He was ordered to reimburse a "significant" but unspecified portion of his Medicaid payments.

Dr. Beale also came under scrutiny for routinely injecting his patients with phenylpropanolamine, an appetite suppressant. A medical consultant for the city said the drug had no clinical value except as a decongestant.

In 1999, Dr. Beale was found guilty in D.C. Superior Court of three counts of sexual harassment and ordered to pay $280,000 in damages to three female former employees who lost their jobs after complaining about his sexual advances. He also was ordered to pay the plaintiffs' legal fees, totaling more than $500,000.

Nonetheless, Dr. Beale's medical license was not suspended, and when the diet drug combination "fen-phen" -- later linked with several deaths -- was introduced in the 1990s, he refused to prescribe it.

"Bob was way ahead of the curve when fen-phen came on the market," said Johnson, the bariatric doctor. "He said, 'Stay a country mile away from it.' "

Dr. Beale was a member of the American Society of Bariatric Physicians, the American Medical Association, the National Medical Association, Omega Psi Phi fraternity and First Baptist Church of Guilford in Columbia.

He owned many high-performance automobiles through the years, including the 500-horsepower Dodge Viper, and enjoyed racing them at Summit Point Raceway near Charles Town, W.Va. He was a member of the Ferrari Club of North America and owned a $200,000 Ferrari 360 Modena, capable of reaching 190 mph.

Survivors include his wife of 42 years, Marilyn T. Beale of Columbia; two daughters, Lisa M. Beale of Washington and Vicki Beale of Columbia; and his father, Dr. Robert S. Beale Sr. of Glenarden.

Lisa Beale said she plans to keep her father's clinics open and "continue the legacy of the work he has done."

Robert S. Beale Jr. was known for his treatment of black women.