Why Are We So Fat?

Maria Signorello has something in common with an astonishing 61 percent of Americans today -- she's overweight.

"I was 9 years old when I first realized I was fat,'' said Signorello.

What followed was a lifetime of diets. Her latest efforts at Weight Watchers are paying off.

"I've lost 14 pounds in 8 weeks," she says.

But losing weight is the exception -- not the rule for most Americans in what has become an epic fight against fat, reports CBS News Correspondent Elizabeth Kaledin.

When did we get so fat? And why? Some trace it back to the industrial revolution, when automation and cars made us less active. Others say the current trend started in the late '70s, when women entered the work force in droves and processed, convenience foods became a necessity.

Whatever the root causes, the result is we are eating ourselves to death. Along with our super-sized meals come hefty portions of heart disease, diabetes, stroke and cancer.

"Americans are in very bad shape today," says Dr. Steven Heymsfield, an obesity expert at St. Luke's Roosevelt Medical Center.

"We have this idea we should never be hungry. So if we feel a little hungry in the middle of the afternoon, we should get a snack and that will clear up our hunger."

In trying to turn the crisis around, doctors are up against a big problem. It turns out that abundant food -- and eating 24 hours a day -- has become our culture. Snacking is the American way.

"Food is everywhere!"

That's the word from Marion Nestle, a nutritionist and author of the book "Food Politics."

"It's considered perfectly appropriate to have kids drink soft drinks. To have people eating on the streets, in the subways, on buses, in bookstores. Any place that you could think of that food could be served – food is served."

It's feeding us -- and feeding a healthy economy.

"There's great profitability in making Americans overweight and also having them continually trying to lose weight," said Heymsfield.

So who's to blame? Not surprisingly, the food industry is being painted as the villain. Critics site a whopping $33 billion a year spent on ads exhorting people to eat more.

The Mars company spent $13 million in one year just to advertise the Snickers bar -- a fortune compared to money spent pushing fruits and vegetables on a hungry public.

But food manufacturers say they are only heeding the call of consumers -- and our lack of activity is also to blame.

"I don't think you can just focus on food," said Lisa Katic, representing the Grocery Manufacturers of America. "We really have to look at calories in, calories out. We can't force consumers to eat or not to eat. They really ultimately make that choice themselves."

Maria Signorello has made a choice. The key ingredient in her weight loss program this time is a single-minded obsession. In this culture of food, she says, it's the only way.

"I think it's impossible without a certain type of resolve that 'I've had it!' I won't let anyone else talk me into another morsel of food that I don't want to eat."

Eye On America
Part 1: Why Are We So Fat?
Part 2: The Typical American Kid — Overweight
Part 2: Willpower In A Pill