That guy peddling the old bicycle down the Chappaquiddick Road ­— he’s a ground-breaking nutritionist, a skilled sailor, a medical official for the last shah of Iran, and a strong critic of recent American policy toward his native land.

 

Not to mention a passionate advocate for Chappy, where he and his wife have stayed for nearly four decades.

 

“We came in 1969 to Chappaquiddick, and immediately fell in love and realized, that’s the place that fits our personality,” Dr. Siamak A. Adibi said, recalling his introduction to the island at the Vineyard’s eastern end.

 

“Houses are unpretentious, people are very lovely, beautiful scenery, beaches untrammeled — and we’ve been coming there ever since,” said Dr. Adibi, now professor emeritus at the University of Pittsburgh School of Medicine.

 

His unlikely journey to the seaside roads of Chappy started 74 years ago in a much different place, in the landlocked city of Tehran, surrounded by snowcapped mountains.

 

By the time he was 15, he knew that he wanted to pursue medicine as a career. Learning that the best medical training in the world could be found in the United States, he boarded a flight for Washington, D.C., undeterred by a big fight with his family, whose members were unhappy with him moving so far away. 

 

Once in Washington, he got on a bus and headed for Baltimore, showing up unannounced at Johns Hopkins University, where he asked in his broken English to be admitted.

 

“They all were very impressed,” he recalls. “They had never seen a Persian. “I seemed extremely adventurous, with no letter of  acceptance or contacting them or letting them know. 

 

“I just came to study medicine,” he said. “They saw my determination. They said I had to learn English. So I spent a few months just practicing English and I went back and they took me as I was.”

 

Appreciating his premed education at Johns Hopkins, but not the lack of excitement in Baltimore in 1950, the young man headed north to Philadelphia, where he obtained his medical degree at Jefferson Medical College. His next stop was at the time the center of the medical universe, Boston, where he obtained a doctorate at the Massachusetts Institute of Technology in nutritional science. That’s also where he decided to pursue research rather than the practice of medicine.

 

Believing he should return to Iran, he met with a government official there about research opportunities.

 

“Adibi,” the official said, “we’d love to have you back. But we don’t have research facilities in the country yet.”

 

Dr. Adibi decided to remain in the United States. “This is where I’m going to have to stay, because I want to do what I want to do,” he said.

 

In his research, he had become intrigued by the lack of attention that American medicine was paying to nutrition as a part of health. He began specializing in the field, drawing the attention of the University of Pittsburgh Medical School, which invited him to set up a section specializing in the study of gastroenterology.

 

At Pittsburgh, Dr. Adibi focused on the problem of American obesity. He decided to pursue an approach that used what essentially was a supervised partial starvation, followed by a regimen of prescribed diet and exercise.

 

He said his approach was popular with patients, generating a waiting list for admission to the program, but less so with insurance companies, which didn’t want to open the door to covering such treatments.

 

Dr. Adibi next analyzed an approach that insurance companies were willing to cover: intestinal bypasses as a way to treat grossly overweight patients. His research showed that the bypasses could cause other damage, in particular liver problems.

 

By the late 1970s, Iranians again were telling the medical researcher that he had an obligation to his native land.

 

The shah of Iran, who had ruled the nation since 1953, wanted to establish a city of medicine north of Tehran, a place that could serve as a medical center for the Middle East. Dr. Adibi previously had met the shah when the ruler recognized him for his academic accomplishments in the United States. The shah offered Dr. Adibi a position as imperial chief of medicine with the new medical center, which was in the midst of construction.

 

Dr. Adibi accepted. But as he was planning his move to Iran and the staffing of his section, Iranian unrest intervened.

 

Much of the Iranian population rose up against the government by the autumn of 1978 in a series of strikes, riots and demonstrations.

 

In January 1979, the shah fled, never to return to Iran. In the coming months, exiled Iranian spiritual leader Ayatollah Khomeni returned to Iran and established an Islamic republic, one with a fierce antipathy to anyone tainted by Western culture.

 

Back in the United States, Dr. Adibi dropped his plans to move to Iran. He turned his efforts toward helping his faculty members escape from Iran, where the new government was executing people connected with the shah’s government.

 

In retrospect, Dr. Adibi sees the shah as a man possessed of both many flaws and some excellent qualities, mixing the idealism embodied by the medical center with widespread repression. 

 

Dr. Adibi said he was unaware of the depth of the anger that Iranians felt toward the shah. He said the population turned to Islamic fundamentalists because the shah’s security forces effectively had eliminated any other sources of opposition.

 

In recent decades, Dr. Adibi said, the United States has been paying the price for wrong-headed policies in the Middle East in general and toward Iran in particular, starting with a failure to understand the motivation for the hostage-taking in 1979, and continuing through President George W. Bush’s ill-fated war in Iraq and continuing efforts to isolate Iran.

 

“Going into Iraq was a trap, and you can see how we’re losing billions of dollars and how our brave young soldiers are trapped in these ghettoes,” said Dr. Adibi, who became an American citizen in 1962. “You’re never going to solve the problems of Sunnis and Shiites and Kurds with American B-52s. This is something that should be solved by their own country.

 

“I’m very upset, because this has increased the power in the hands of the extremists, and now with the Israeli fiasco following the American thinking that Hezbollah and Hammas can be treated by fighter planes — the same error. There has to be a diplomatic negotiation and compromise.

 

“These people are fighting because they feel they have been denied their rights, and you’re going to make them more angry by doing this,” he said.

 

He has been surprised by the lack of knowledge that Americans, including highly educated ones, have about Iran and the Middle East. He now hopes to emulate Vineyarder David McCullough by writing a book to help make Iran’s history come to life.

 

Closer to home, Dr. Adibi and his wife, Joan, have been working to preserve the special nature of Chappaquiddick, their adopted summer home. Those efforts, however, have encountered a number of hurdles.

 

“We’re concerned about the aquifer on Chappaquiddick,” Dr. Adibi said. “If it goes, we go. There’s no water system.”

 

But the Edgartown planning board declined to pursue his recommendation to require minimum one-acre zoning on Chappy to help protect the aquifer.

 

More recently, the Adibis’ efforts to promote affordable housing for working-class Vineyarders on Chappy have faced continuing legal challenges and strained personal relationships.

 

“One of my very closest friends will not talk to me anymore, so we have paid a price,” he said.

The Adibis, however, aren’t going anywhere. On the water, Dr. Adibi, a member of the Edgartown Yacht Club, delights in his Rhodes 19, named Eroica in honor of Beethoven’s Fourth Symphony. 

 

On land, Dr. Adibi is a bicyclical omnipresence on the roads of Chappy, which are all dirt save two. His avid riding, it turns out, has a rational underpinning.

 

“I’m concerned about the environment, so I want to avoid fossil fuel pollution,” he said. “And our economy is hostage to foreign oil, so I hate to drive a car unless I have to. And actually, it was a great way to meet people. I became known, and I met many people on my bicycle.

 

“And there’s a fourth reason,” Dr. Adibi said. “I love to eat, and this is one way to keep my weight down. Biking 10, 20 miles a day, it really helps. The only way I think I’ve been able to control my weight is by all the biking.”

 

When Dr. Adibi hops on his bicycle, he makes certain it’s an old one. In fact, he owns a fleet of old bikes.

 

“They’re less likely to be stolen,” he said. “And I live in dirt and sand. I don’t need a fancy bike. When one dies, I get another one.”