Oliver, 31, has spent the past several years crusading for healthier food in British schools with a television series that aired last year and a government-backed overhaul of school catering. Now he wants the United States to address the issue.
"England's the most unhealthy country in Europe and America is the most unhealthy country in the world," Oliver, known for his frank opinions, told REUTERS in New York while promoting his latest book and television series on Italy.
The Essex, England-born chef started cooking at age 8 at his parents' hotel before his first book and television series, "The Naked Chef," made him famous at the age of 21 in several countries and spurred more books and shows.
Oliver said U.S. politicians should "stop being so subservient" to "junk food companies" and that the country should cut down on junk and fatty foods, which would help reduce future health costs.
"A fat person in England isn't the same as a fat person in America," he said, asserting that America's obesity problem was far worse.
In the United States, the percentage of overweight young people has more than tripled since 1980, according to the U.S. Centers for Disease Control and Prevention.
The obesity rate for U.S. children and youth rose from 16 percent in 2002 to 17.1 percent in 2004. It is projected to hit 20 percent by 2010.
Oliver said clearer government guidelines were needed, such as New York City Mayor Michael Bloomberg's recent proposal for a near ban on artificial trans fat in restaurant food.
"The junk food companies have got more resources than the government and more money to spend on poxy lawyers so I completely admire and condone the mayor for doing it," he said.
But unlike in Britain, he won't personally take on the U.S. crusade. "I'd love to do it but I don't know if I have got it in me," he said.
Oliver said TV cooking guru Rachel Ray might be a better advocate. "(As an) English boy in America, they might not appreciate my honesty," he said.
Oliver's latest book "Jamie's Italy" was released in U.S. bookstores earlier this month and his television series "Jamie Oliver's Great Italian escape" will debut in the United States this month.
Image: A menu for fried chicken and french fries is displayed on a wall at a fast food restaurant in New York, October 30, 2006. REUTERS/Shannon Stapleton/file