But Altarum researchers say data on children ages 5-14 are scarce and among children under 5, only those enrolled in public assistance programs are counted.
"The advantage of the registry-based clinical model is that it focuses on the youngest children -- where we have the best chance of preventing obesity from developing in the first place," said co-author and Altarum fellow Matt Longjohn.
"The clinical model also reminds providers to screen children and how to counsel them and their families according to established standards."
Two bills in Congress have been introduced that would provide grants through the Department of Health and Human Services to help states develop and expand their immunization registries.
Some studies estimate that the epidemic costs the nation $1,000 per person, per year in health care costs -- about $150 billion or 10 percent of overall health care expenditures.
"And the end is not in sight," said Longjohn. "We are developing a generation of kids with adult risks before they leave adolescence."
About 30 states have implemented or considered BMI surveillance programs, most of them school-based, like the one in Arkansas that was launched in 2003.
"In an ideal world, the doctor has a list of who is coming in that day and the immunization registry tells him they need this shot, this lead test follow-up and height and weight assessed and the BMI checked to see if they are overweight and if they are, kick in with other screening tests," said co-author and senior policy analyst Amy Sheon.
With the registry-based model, personally identifiable information never leaves the doctor's office and the only data shared is aggregate information on rates of obesity.
But some parents object to surveillance as an "intrusion by well-meaning adults."
"I have no problems with government publishing information regarding the effects of obesity and educating the public on this issue," said Scott Hipsak of Anchorage, Alaska.
"Further rules and regulations will not address this issue," he said. "People will eat what they want when they want it and you cannot change that."
He insists advertising, like anti-smoking campaigns would be more effective.
"I have one skinny to medium child and one child who has always, always been off-the-charts for weight since she entered the world at 9 1/2 pounds," she said of her adopted 5-year-old. "It's how she's built. It's how her family's built."
"She is also very active, eats a wide variety of healthy foods and is sick the least of us so to take her weight as a measure of her entire health would be a huge mistake," said Friedman, 40.
She is also frustrated by efforts to "shame" children and parents, rather than providing healthier school lunches, and making good food more affordable in neighborhoods where shopping is a challenge.
But other parents agree that the state should take on a larger role.
"If I had failed at being a good parent by letting my child get fat in the first place, yes, I would welcome help from a doctor," said Ann Joyce of Liberty, N.C. "Health trumps privacy when you have failed as a parent. Parents need to wake up to what they are doing to their kids."