OMAHA, Neb. -- The obesity rate of children between the ages of 6 and 11 has more than doubled since the late 1970s. The number of obese adolescents has tripled since then.

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The trend prompts a lot of finger pointing. Who's to blame? The government? Advertisers? Parents?

Experts say it is all of the above, but pediatricians and parents can have the most impact on reversing the trend.

Too often, parents are silent or complicit about their children's weight.

"There's research showing that when guardians or parents of overweight kids were asked if their kid was overweight, they said no, they didn't see it," said Dr. Ann Grandjean, at the Center for Human Nutrition.

It's human nature to become defensive when confronted with a problem.

"You try to address it with parents early on," said Dr. Pat McCarville, a Omaha family physician. "A lot of times you get a deer in the headlight look. 'I feed my kid what I need to, don't bother me about it.'"

Adding to the problem, many doctors feel squeamish about addressing childhood obesity.

"We did a survey with pediatricians. Sixty percent said when they saw a child that's overweight, they weren't comfortable approaching the parent about it," Grandjean said.

"If you set the family off negatively, you'll never get cooperation from families, and you won't accomplish goals," said Dr. Charles Sprague.

Sprague said doctors choose their words carefully, especially if the parents, themselves, are overweight.

"What's frustrating as a physician, it's very unusual to encounter an overweight child with two very fit parents," said McCarville.

McCarville said part of the problem is how we perceive obesity. Many still believe it's an aesthetic issue, when in fact, obesity is a medical crisis. Like any other medical crisis, it requires intervention.