K. Dun Gifford, who started an influential nonprofit organization to combat obesity and promote healthy eating around the world, and whose well-connected life put him in celebrated company and at the scenes of many newsmaking events, died on Sunday in Exeter, N.H. He was 71 and lived in Cambridge, Mass. The cause was a heart attack, his son Dun Gifford Jr. said. After graduating from Harvard Law School, Gifford carved out careers in politics, real estate and business. He was also a bon vivant and a sometime restaurateur who traveled with gregarious ease in social circles of the famous and accomplished, and he had plenty of stories to tell. As a teenager, he survived the wreck of the Andrea Doria. And his early experience in politics working for two Kennedys made him a witness to the assassination of Sen. Robert F. Kennedy and the immediate aftermath of the automobile accident on Chappaquiddick Island that implicated Sen. Edward M. Kennedy in the death of an aide, Mary Jo Kopechne. He became best known as the president of Oldways Preservation Trust, a nonprofit organization he founded in 1988 to address the issue of nutritional eating in an era of fast food. Oldways has created educational programs, organized conferences and developed and promoted models for balanced and sustainable diets. Opposing fads that rely on edicts like banishing fats or carbohydrates, Oldways has been an advocate of the so-called Mediterranean diet, which emphasizes food from plant sources, using olive oil as the principle source of fat and avoiding processed foods. Under Gifford, Oldways created several advocacy groups, including the Whole Grains Council, which works to increase the consumption of whole grains, and, along with the American Cheese Society, the Cheese of Choice Coalition, which successfully lobbied against a threat by the Food and Drug Administration to limit the sale of unpasteurized cheeses. 'We need to teach people that food is glorious and that you don't have to eat a whole lot of it to be satisfied,' Gifford said in an interview with The Financial Times in 2005. Early in his career, Gifford worked in Washington for the Department of Housing and Urban Development before becoming a legislative aide to Sen. Edward Kennedy. He later became national campaign coordinator for Sen. Robert Kennedy during his bid for the Democratic presidential nomination. On June 5, 1968, he was walking behind Kennedy through a pantry in the Ambassador Hotel in Los Angeles when an assassin, Sirhan B. Sirhan, shot the senator to death. In photographs, his son said, Gifford can be seen in the scrum that wrestled Sirhan to the ground. In July 1969, Gifford was called by Edward Kennedy's office to assist in handling the death of Kopechne, a former secretary for Robert Kennedy. Gifford accompanied Kopechne's body back to her home state, Pennsylvania, for burial. Days later Kennedy pleaded guilty to leaving the scene of an accident, resulting in a two-month suspended sentence. Kilvert Dun Gifford was born in Providence, R.I., on Oct. 23, 1938, the son of Clarence H. Gifford Jr., a banker from Kentucky, and Priscilla Marshall Kilvert. He attended private schools in Rhode Island and studied English at Harvard. He was returning from Europe with his family in 1956 on the Italian luxury liner Andrea Doria when it was rammed by the Swedish ocean liner Stockholm 45 miles south of Nantucket. Fifty-one people died in the collision; the Giffords were among the 1,660 rescued. The experience did not discourage him from going to sea. Gifford served in the Navy from 1960 to 1963, and the next year, as a competitive sailor, he was the navigator aboard the yacht Constellation in its successful defense of the America's Cup. Gifford worked in commercial real estate in Boston in the 1970s and '80s, and he invested in several restaurants, including Harvest, in Harvard Square. He maintained a long friendship with Julia Child, with whom he shared a fondness for martinis and McDonald's French fries. In 1976, with a lawyer friend, John Kerry, who would become a senator from Massachusetts and the 2004 Democratic nominee for president, he founded Kilvert & Forbes, a cookie company. (They later sold their interests in it.) Gifford married Gladys C. Porter in 1960; they divorced last year. In addition to his son, Dun Jr., he is survived by his companion, Sara Baer-Sinnott, who is executive vice president of Oldways; two brothers, Charles, the former chairman of Bank of America, and John; a sister, Priscilla Mleczko; two other sons, Arnold Porter Gifford and Clarence Hamilton Gifford; a daughter, Caroline Ames; and five grandchildren. 'He was a cheerful and optimistic fellow, without, in some cases, reason to be,' said his friend Russell Morash, the producer of 'This Old House' and other TV shows. Asked if his friend had an ego, Morash said, 'Inevitably.' 'We'd go sailing, and in the densest fog bank, he'd claim to know where every landmark was,' Morash said. 'Whether he actually did was a question. He loved to tell the story of Chappaquiddick. He loved to talk about the Andrea Doria. He loved to gather an audience and tell them the truth -- from his perspective.' 