Since 1980, childhood obesity has tripled in the United States. In Texas, more than 30 percent of children are either overweight or obese. If something isn’t done soon, our kids will be doomed to a shorter life filled with chronic disease. Amazingly, a lot of this could be avoided if we reduced our children’s daily caloric intake by just 110-165 calories. That’s, like, half a Snickers bar!

Speaking of Snickers, did you know that half of U.S. elementary school students can buy unhealthy snacks such as candy, cookies, cakes and baked goods outside of school meals? These are the so-called “competitive foods,” and they are virtually exempt from federal regulation.

Schools are prohibited only from selling soda, gum and some candies in the cafeteria during lunchtime. However, competitive foods may be sold elsewhere in school through vending machines and school stores, even during lunch. And, by the law, the schools make a lot of money housing these vending machines — about $2 billion nationwide.

For years, public health experts have urged local and state governments to remove competitive foods from schools. In recent years, many states have started to pass competitive-food laws that restrict their sale, either banning them outright or setting limits on the amount of sugar, fat or calories they contain.

These laws cover food from vending machines, for instance, and those sold à la carte in the cafeteria or in fundraising projects for school teams or organizations. Interestingly, those states without any laws or weak laws — like Texas — have the highest childhood obesity rates.

Until now, the impact of these competitive-food laws on weight gain was not known. So it was easy for the skeptics to object to messing with our little darlings’ candy bars. Finally, last week, the impact of these laws was revealed in a pivotal study published in the journal Pediatrics titled, “Student Access to Competitive Foods in Elementary Schools: Trends Over Time and Regional Differences.”

The study tracked weight changes for 6,300 students in 40 states between 2004 and 2007, following them from fifth to eighth grade. They used the results to compare weight change over time in states with no laws regulating competitive foods against those in states with strong laws and those with weak laws.

The researchers grouped competitive foods into categories: Healthy foods included fruits, vegetables and salad; unhealthy foods were grouped as sugary (candy, baked goods, ice cream) and salty (pretzels, potato chips).

Most important, the study’s authors classified the laws as strong if they required schools to sell only foods that met specific nutrition standards. The laws were weak if they recommended but did not require sales of healthy foods, or if they used general language such as “healthy.”

Students who went to a school with strong laws in fifth grade gained, on average, 2.25 fewer pounds for a 5-foot-tall child who started out at 100 pounds in 2003 than students in schools with no such laws.

Thus, students exposed to strong laws gained less than those who were not, and they were less likely to remain overweight or obese over time compared to students in states with no such laws. Up until now, nothing that’s been done has had any effect on childhood obesity levels.

The study results show that “competitive food rules are incredibly important,” said Dr. Marlene Schwartz, deputy director of the Rudd Center for Food Policy and Obesity at Yale University.

“We have found that kids eat less junk food when there is less junk food in schools,” she said. However, “this is the first big national study that looked at the laws.”

“Competitive-food laws in schools reduce weight gain if they are strong and consistent,” Dr. Daniel Taber, the study leader, said.

Children eat about half their daily calories at school, so it stands to reason that replacing unhealthy competitive foods with healthy choices would reduce obesity. Hopefully, children will also learn about good eating habits that will lead to healthier lifestyles.

Later this year the U.S. Department of Agriculture is going to release new guidelines for school nutrition. Hopefully, these encouraging results will lead to rules against competitive-food sales in schools.

Until this happens, parents who live in states without strong competitive-food laws, including Texas, are encouraged to get involved and advocate for your children. After all, it’s their futures we’re talking about.