Back in 2010, the Rodriquez household changed their definition of fast food to mean a whole grain banana sandwich, a far cry from what they used to eat, and what their mother grew up on.

"Soda and we could pick out all the Doritos, all the chips," said Rosa.

She started worrying though after son Alfredo became overweight, because many of her family members have Type 2 diabetes. That's why she enrolled her family in an intensive five-month long study at Seattle Children's focused on healthy eating. The results were impressive and long lasting.

"We have an intervention that we know is really effective," said Dr. Brian Saelens who led the study.

Only one problem.

"This treatment is so expensive and health insurance doesn't cover it and so families are stuck," he said.

Now Seattle Children's is launching a bigger study with a twist.

"Can we treat families and then have parents of those families go on to treat the next set of families in a peer to peer model?" Saelens asked.

The SHIFT study (Success in Health: Impacting Families Together) hopes to enroll 300 eligible families over the next four years,

"Kiddos who are 7-11 years old who are at least above the 85 percentile for their BMI so heavy for their age and gender. They have to have at least one overweight parent," said Dr. Saelens.

That's because those children are more likely to stay overweight, so the focus need to be on the entire family. It's all about changing behavior.

The hope is that if the peer-to-peer model proves successful, this kind of treatment will become much more cost-effective and available to many more families who need it.

The study is being funded with a $2 million grant from the National Institutes of Health.