Experts also believe children's poor diets are a result of their home environment.
"Eating is learned behavior. Kids eat what their parents eat," said Dr. Charles Clark, professor of medicine at Indiana University School of Medicine. If busy parents throw a frozen pizza in the microwave, he said, that's a bad meal that sends a bad message.
"[We need] better food labeling, including fruits and vegetables, clarification of serving sizes ... [and] food labeling with caloric content," said Dr. Robert Eckel, a professor of medicine at the University of Colorado Hospital.
One nutritionist said that while the food industry does serve up a less-than-healthy dose of junk food, restaurants are improving their choices, and it's up to consumers to make the right choices.
"[W]e need for customers to continue to ask for healthier options. Change won't happen in these environments unless customers financially support the changes," said Diekman.
The Grocery Manufacturers Association, an organization that represents 300 food, beverage and consumer product companies, said that between 2002 and 2009, food and beverage companies have introduced thousands of healthier alternatives.
"Food and beverage companies are responding to consumer needs by providing thousands of healthier product choices that make it easier for shoppers to build a healthy diet for them and their families," the association said in a press release.
The association also said more than 90 percent of its companies actively promote healthy lifestyles.
Despite the National Cancer Institute study's findings, the director of the U.S. Centers for Disease Control and Prevention called the obesity epidemic a "winnable battle."
"CDC is committed to addressing the epidemic of obesity and overweight in the U.S.," says the agency's website, "and improving the public's health through the promotion of good nutrition, physical activity, and a safe food supply."