I fear for the future of America. It's not due to the economy's slow recovery and the millions of people looking for work, or the threat of terrorism posed by Al Qaeda's unwavering determination to wreak death and destruction on US soil.

My fears are based on what Americans are doing to themselves, and in particular, to the health of their bodies.

I took an early morning flight from Miami to Washington the other week. I decided to grab some breakfast at the airport. But little did I know my choice would be so limited. It wasn't for lack of eateries in the terminal - just none of it appealed to me.

There were grab-and-go pizzas, donuts and pastries including giant cinnamon buns, cakes, sandwiches dripping in mayonnaise (I hate to think what was in it) and using bread that was so high in sugar, it was off the charts.

I hunted down a chain coffee shop in the hope of finding some fruit and yoghurt, and as I sat down with other passengers to eat my not-so-healthy option, I was shocked at how many Americans had chosen pizza for breakfast at 8am.

It's little wonder this country has an obesity problem.

A report by America's Institute of Medicine released last week found that obesity is so entrenched in the US that it would take an intense push by schools, employers, doctors and others to reverse an epidemic that accounts for billions of dollars in annual health-care costs.

Two thirds of Americans are overweight or obese, and the number of people who are severely obese continues to rise. By 2030, statisticians predict 42 per cent of American adults will be obese – that's 110 million people who will be eating their way to potentially early deaths.

These are fairly disturbing statistics.

Food generally in the United States is reasonably priced. Good eating choices are available, but corporate America has made it too easy for people to eat junk food – it's cheap and some of it doesn't taste too bad.

So how did a country that describes itself as the greatest country in the world become one of the fattest countries on earth? To answer this question I spoke to Tyler Cowen, an economist and the author of an online dining guide in the United States.

He told me that historical accidents are to blame for the decline of food in America. First there was the Prohibition, which sent many restaurants bankrupt because they couldn't make a profit on food alone, then came the Great Depression, and then the baby boom, where children's taste buds took priority.

In his new book An Economist Gets Lunch, Tyler Cowen writes, "When the kids are in charge, food quality is bound to go downhill, and that has been a big part of the problem with American food."

One of the most interesting observations Cowen makes is that the American poor are more likely to be obese than starving. Mr Cowen says there's plenty of cheap food in America, but a lot of it is too sweet and a lot of is not good for us.

But, he argues, taxing junk food won't change people's eating habits. He points out that if people are determined to overeat, then they will do so whether there's a tax on food or not.

The report by the Institute of Medicine recommends that Americans create environments that ensure that healthy food and beverage options are routine including "increasing the availability of lower-calorie and healthier food in restaurants".

The authorities here in the US could also think about offering healthy option restaurants at airport terminals, where in my humble opinion pizzas should only be offered after midday!

This piece is based on Stephanie Kennedy's interview with Tyler Cowen for One Plus One which airs today at 11:30am and 2:30pm on ABC1, and 8:30pm on ABC News 24. The interview will be available on the program website after broadcast.

Stephanie Kennedy is a senior reporter with the ABC based in Washington. View her full profile here.