When I was a kid, one of the highlights of the school year was when a classmate would bring in cupcakes to celebrate their birthday.
That has changed with my own daughter. Her elementary school only allows healthy birthday treats or an appropriate alternative, like pencils or stickers.
And that's not unusual. Over the past decade, schools have cracked down on the consumption of sugary drinks and junk food. And in 2014, the U.S. Department of Agriculture implemented its Smart Snacks in School regulations, which banned junk food from being sold in school cafeterias, vending machines, and fundraisers during school hours at schools that participate in the National School Lunch Program.
The idea behind the changes is to limit the amount of fats, sugars, sodium, and calories in school foods in an effort to promote healthy eating and curb childhood obesity, according to Scholastic.
And while these measures may be working, a study published this week in the journal Obesity suggests the risk of obesity is actually higher when kids are out of school than when they are in school. It's only the most recent in a number of studies that have suggested the trend.
Researchers followed 18,170 kids in the U.S. from the fall of kindergarten in 2010 through the spring of second grade in 2013. They found the prevalence of overweight increased from 23.3% to 28.7%. All of the increase occurred during the two summer vacations. No increase occurred during the school years.
Although there's no definitive data for exactly why kids pack on pounds during summer vacation, the study suggests major risk factors for childhood obesity lie outside of schools.
According to researchers, kids may be more sedentary during the summer months, spending more time watching TV and using other devices. The American Academy of Pediatrics previously linked screen time to a higher risk of obesity starting in early childhood.
And without a consistent schedule, kids may also sleep less, which has been discovered to slow metabolism, encourage weight gain by boosting hunger, and slow the rate at which calories are burned.
Jennette Moreno is a clinical psychologist at the Children's Nutrition Research Center at the Baylor College of Medicine. She told NPR:
It does seem that kids sleep less during the summer or have more irregular sleep-wake patterns, and disrupted sleep is associated with higher BMI. My hypothesis is that without the structure of school, kids are going to bed at irregular times and parents are more relaxed about enforcing bedtimes. As a result, children's sleep and circadian rhythms are disrupted.
Study authors say out-of-school behaviors have to be changed to avoid summer weight gain. The study recommends things like summer camps and summer learning programs to keep kids busy. Also, sticking to consistent meal and sleep patterns. Amanda Staiano is spokesperson for The Obesity Society. She told Endocrinology Advisor:
We hope these findings galvanize efforts by parents, educators, public health advocates, and officials to make sure that summer does not set back efforts made during the school year to not just teach our children, but to keep them healthy.