WATERLOO - More than one-third of adults - 72 million people - and 16 percent of children in America are obese.

The Centers for Disease Control and Prevention calls it an epidemic. Obesity doesn't discriminate - every age, ethnic group and education level is affected.

Many people blame the nation's farm policy for its weight problem. Some believe doling out farm subsidies based on production encourages farmers to overproduce corn, soybeans and other commodities. That eventually resulted in cheap, unhealthy foods being produced and consumed.

Farmers and commodity groups say that's hogwash. People are responsible for what they eat and the farm program has little or nothing to do with it.

Yet other health experts and farm advocates say the obesity issue in America - which people concede is a problem - is too complex to blame one group or government policy.

Obesity is defined as having a very high amount of body fat in relation to lean body mass. A body mass index of 30 or higher is considered obese, according to the CDC.

"There's not one thing to put your finger on that's the sole source of obesity," said Doris Montgomery, community health consultant and dietitian for the Iowa Nutrition Network at the Iowa Department of Public Health. "Oh yes, obesity is definitely on the rise. It's a serious problem."

Just because Iowa is a blue-collar state filled with active farmers and factory workers doesn't mean citizens will be healthier than the rest of the nation. Montgomery estimates 60 to 65 percent of Iowans are overweight or obese.

In fact, Iowa has followed the trend of rapidly rising obesity rates nationwide during the past 20 years. In 1990, there were 10 states with an obesity rate of less than 10 percent and no states at or greater than 15 percent. A year earlier, Iowa ranged from 10 percent to 14 percent.

By 2007, only Colorado had an obesity rate of less than 20 percent, while 30 states had rates equal or greater than 25 percent. Three states were more than 30 percent. Iowa was at 26.9 percent.

According to the CDC, obesity contributes to health problems such as type II diabetes, heart disease, hypertension, cancer and stroke, just to name a few.

"There's no way to blame just farmers or food products. It's the whole package," Montgomery said.

The mission of the Environmental Working Group, based in Washington, D.C., is to protect public health and the environment. The group primarily blames what it considers a broken farm subsidy program for the obesity problem. It annually compiles a list of subsidy recipients and amounts - available on its Web site, www.ewg.org - hoping the public will become upset enough to demand change.

Subsidies were created during the Great Depression to keep farmers in business. Back then, more than 20 percent of the population made their living off the land.

Farming is a volatile business, in part because producers can't control the weather, inputs costs or commodity prices, so subsidies stayed. Lawmakers and farm groups believe they provide an economic safety net, which in turn provides a reliable and affordable food supply.

EWG data shows taxpayers paid farmers $34.8 billion from 2003-05, and 66 percent of the payments went to 10 percent of the beneficiaries. Spokeswoman Michelle Perez said highly subsidized crops like corn and soybeans create an overabundance of cheap processed food, oils and sweeteners that are calorie-rich and nutrition-poor.

"Absolutely we think there's a link. We end up with food that hurts people's health," Perez said.

The Institute for Agriculture and Trade Policy in Minneapolis released a report called "Food Without Thought" in 2006. It said the primary driver of over-consumption of calories is the farm policy.

The report said, "the low cost of commodities like corn and soybeans make sugars and fats some of the cheapest food substances to produce. Whether by intention or not, current farm policy had directed the food industry investment into finding ways of using cheap food additives in processed foods."

High fructose corn syrup, often used in soft drinks, and hydrogenated vegetable oils used in cooking were highlighted in the report. Advocates for farm policy change said, prior to the last 1 1/2 years, low-cost grain also spurred livestock production. For example, cattle moved off pastures and into feedlots because feeding corn was a fast and cheap way to fatten cattle. However, this also resulted in more marbling, or fat in the meat that contributes to obesity.

A recently released documentary called "Food Inc." largely blames food companies and farm policy for obesity. Filmmaker Robert Kenner said subsidized corn and soybeans are in virtually everything from hamburgers to french fries. The film shows a young, obese family that prefers eating drive-through fast food instead of fresh fruits, vegetables and lean meat. Kenner claims, "were paying money for food that's making us sick."

As a nurse and farmer, Pam Johnson of Floyd knows obesity is a serious health issue, but she isn't to blame. When it comes down to it, Johnson said people are responsible for what goes in their bodies and how much they exercise to stay trim and healthy. However, she also realizes medical problems make it difficult for some people to lose weight.

"Obesity for me is a lack of knowledge. Moderation is the key: Calories in mean calories out," Johnson said. "Farm policy gets blamed for a lot of things that are disconnected."

The Iowa Farm Bureau Federation, the state's largest farm organization, believes farm policy encourages production of basic commodities, which helps keep the state's economy healthy. It's up to people to keep themselves healthy, a spokesman said.

Dave Miller, director of research and commodity services with the federation, said farm policy allows the United States to feed the world, and Americans spend less income on food than most other nations, which frees up money to be spent elsewhere.

"It's a stretch to say it (subsidies) relates to obesity. The correlation is not a causality," Miller said.

Sen. Charles Grassley of New Hartford knows how to combat the obesity problem, and it's not by eliminating farm subsidies. He's been a longtime advocate of farm programs, saying producers need a safety net. Abundant, affordable food also plays a key role in national security, Grassley contends.

To fight obesity, Grassley said people simply have to watch their diet and calorie intake. He said there's plenty of healthy food that's affordable.

"I don't know how you can blame the family farmer or even people in between for … for people eating too much," Grassley said. "So you've got to put it on the backs of the people that are making the decisions to do what they're doing."