Anyone who’s gone on a diet knows: It’s easier to avoid potato chips if you don’t have any.

So it’s not a surprise that researchers found that California high school students eat less fat and sugar and fewer calories at school than their peers in states that allow the sale of snacks with more of those items.

What’s more, the California students didn’t compensate outside of school; they ate an average of 158 calories a day fewer than students in the other states, according to the study published Monday in the Archives of Pediatrics and Adolescent Medicine.The California students’ consumption outside of school was approximately the same as the students in the other states.

The researchers repeated their analysis with only Hispanic students, a population with particularly high rates of obesity, and found similar results.


“If students can consume 150 fewer calories per day while maintaining healthy levels of activity, it could go a long way toward preventing excess weight gain among teenagers,” said Daniel Taber, lead author of the study and an investigator with Bridging the Gap, a research program of the Robert Wood Johnson Foundation, which funded the study.

California was among the first states to regulate what’s known as “competitive” foods – those sold at school outside of the school meals programs -- in vending machines or student stores, for instance. The law took effect in July 2007 and limits competitive snacks to 35% of total calories from fat (10% saturated fat), 35% of its weight from sugars and no more than 250 calories. Competitive entrees can be 400 calories, with 100 calories of fat.

Nationwide, high school is far from junk food-free: 77% of high schools offered regular-fat and sugar snacks in 2007-08, the researchers said.

The researchers compared 114 California students with 566 teenagers in 14 states without laws governing fat, sugar or caloric content of competitive foods in May 2010 by asking them about what they ate in the previous 24 hours. (If you’re wondering about teenage reliability, the researchers noted that that could be an issue.)


Competitive foods, the researchers note, “are commonly foods of high caloric density and low nutrient density.” That, we presume, is how they compete. We’re sure there are teens who regularly choose celery over ice cream, but we also guess they’re few and far between.

This all matters because the Health, Hunger-Free Kids Act of 2010 requires the federal government to come up with standards for competitive foods in schools that take part in the federal school meals program.

There is no way to prove from the study alone that California’s laws were the cause of the differences that researchers observed, Taber said. But he also said the findings suggest that strong nutrition standards -- such as requiring that at least half the grains be whole -- may be an effective way to reduce teenage weight gain.

The regulations in California are a start, he said.


“California schools were getting the unhealthy foods out, but they were not necessarily replacing them with healthier alternatives,” even if the new foods – baked chips, say -- met the standards, Taber said. “Just because a student isn’t eating a candy bar, they are not necessarily eating a spinach salad in its place.”

You can read an abstract of the study here.

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