By Daily Mail Reporter
Big challenge: Jamie Oliver looks flustered as David Letterman argues why his healthy eating plan won't work on The Late Show last night
Jamie Oliver's attempt to revolutionise America's unhealthy eating habits hit yet another stumbling block yesterday when his plan was dismissed by David Letterman.
In a move away from his talkshow's usual format, the TV host delivered an extraordinary five-minute lecture at the start saying why Oliver was doomed to failure.
While Letterman praised Oliver's idea, he said it wouldn't work in a country full of fast food chains and convenience food.
Passionate: Oliver tries to convince Letterman to his way of thinking
Oliver chatted to Letterman during a cooking segment on The Late Show last night as he promoted his new TV show Jamie Oliver's Food Revolution.
The six-part series sees Oliver travel to the city of Huntington, Virginia - known as the most unhealthy city in America - in a bid to overhaul their eating habits. He actually bursts into tears of frustration as his message fails to get through.
Letterman started off the segment by outlining his thoughts on why Oliver's healthy eating plan wouldn't work.
He said: 'You know who was on the programme last week was Kirstie Alley and she has a kind of second career dealing with her weight and her struggles to lose weight.
Giant problem: Residents of America's fattest town, Kristin Cookson and Justin Peterson study in Starbucks between meals
'We got to talking about how difficult it is for people to lose weight and I maintained that try as hard as you might you are never going to succeed because we are living in a culture dominated by the commerce of selling food that is inherently unhealthy.'
Oliver said despite the dominance of fast food, he hoped to educate people about what they were putting in their bodies and the health problems they will face in the future.
However, Letterman fired back he had battled weight problems himself and controversially believes diet pills are the only successful way to lose weight in America.
Big appetitie: A Huntington chef prepares one of the town's specialities... a 15lb burger
He said: 'After five or six, ten or 20 years of trying to lose weight there is nothing in this culture you can do to lose weight short of medication.
'If you want to go to a doctor, no seriously, go to a doctor and they'll be happy to give you as many pills as you need.
'But as long as we are trying to feed this many people we are going to continue to eat bad food. And you think McDonald's is going to close down? No, they're not going to close down.'
Letterman then gave several examples of why Americans didn't like change: 'In the late 60s we were going to be changed to the metric system... well that didn't work, did it? And you know why? It was too hard for Americans to figure out metres.
'Soccer, remember soccer? Well that didn't work either.'
Oliver interjected how the smoking ban - in New York and several other U.S. cities - had been successful, despite the initial outrage from smokers.
Emotional: Oliver cries with frustration after clashing with dinner ladies in Huntington
Letterman replied: 'But again that was people making the decision. With eating it's not a decision. People have to eat.
'God bless you but here's what I think will happen. I think that the species will evolve to the point where 1,000 years from now we all weigh 5-600lbs and it will be OK.'
Oliver insisted the increasingly unhealthy lifestyles of today's children meant they would be living shorter lives than their parents, which Letterman agreed on.
But he blamed America's food industry for making unhealthy food so available: 'We'll go into any supermarket and there are 160 different kinds of cookies.
'I don't care how much ground up sea grass you eat or wheat germ - or stuff you find in your pocket. As long as they are selling 160 different types of cookie what hope do you have?'
Oliver appeared to become resigned to the fact he wouldn't convert Letterman to his way of thinking, turning to the audience and saying: 'As you can see ladies and gentlemen, my challenge is big.'
Poor diet: Mother-of-four Stacie, surrounded by a week's worth of deep fried food, starts to cry as Oliver tells her that her cooking will kill her children
In Oliver's new show, he reduces an American mother-of-four to tears when he warns her that her cooking will end up killing her children.
Sitting in front of a pile of the family's weekly food intake, Oliver tells a weepy Stacie: 'This is going to kill your children.'
Her son Jamie, 12, admits he is picked on at school due to his large size and hopes to become a chef.
Oliver's new series sees him hoping to reciprocate his success in Britain, where he overhauled school dinners.
Oliver is shocked when he sees dinner ladies making pizza for breakfast and served instant mashed potatoes to children at Central City Elementary.
Amazed that they're not using real potatoes, he points to the mash, saying: 'It's that kind of food that is killing America.'
An incredulous Oliver is further stunned when he holds up tomatoes on a vine to a young boy, who believes they are potatoes.
The chef stands back as he watches the children eating and notices they are all drinking flavoured milk and are uninterested in fruit.
Using shock tactics to explain to the children and staff how much fat they're eating every year, they eventually are open to change.
During the series, a local newspaper claims Oliver has said several disparaging things about Huntingdon, which he insists was taken out of context.
An emotional Oliver is seen tearing up as he says: 'They don't understand me 'cause they don't know why I'm here.'