Saturday, January 30, 2010

Slimming Down School Milk: Did it have an impact?

Schools are getting smart and thinking more about where kids are getting their calories from in school. With childhood obesity continuing to rise (even though adult obesity seems to have slowed down), the implementation of sound school wellness policies is imperative to curbing unhealthy habit forming behaviors in kids' lives.

There is not a ton of data on how school nutrition policies have impacted student health or changed children's consumption of certain foods. (Though if you're interested, I've done a ton of research in this area on sugar-sweetened beverages). But now we have data on one common policy: switching school cafeterias over to serving kids lower-fat milk (1% or fat-free).

While every school district must have a wellness policy that documents the school district's position on nutrition and physical education, school meals, competitive food (a.k.a. school sold outside of school meals) and other wellness issues, the monitoring and evaluation section of wellness policies is usually lacking.

Often times its unclear who is charged with monitoring or implementing the school's wellness policy. It's rare to find a policy that describes what metrics will be used to evaluate its success. It's no surprise then, that we don't have much data on what school nutrition policies are most effective in promoting kids' health and which are less so.

Thankfully, when it comes to switching over schools from whole or high-fat milk to low-fat or fat-free milk, evaluation results have begun to surface!

An article on highlighted a study out of NYC, which found that the switch to low-fat and fat-free milk resulted in

  • An increase in student milk purchases by 1.3%
  • A reduction in 5,960 calories from milk served to milk-drinking students annually
  • A reduction in 619 grams of fat from milk served to milk-drinking students annually
The findings come from this week's publication from the Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.

The only problem I see with the reporting of the study (and perhaps the study itself) is that it doesn't mention comparing the changes in consumption, calories, and fat to a similar school or school district that didn't switch to low-fat or fat-free milk entirely. For example, perhaps milk consumption increased among students in all schools because it was being promoted more heavily in media and by food service staff. It may have had nothing to do with the switch to low-fat or fat-free products.

Giving students the choice of fat-free and low-fat milk is important. And switching over entirely to low-fat and fat-free milk is a great public health intervention. These results show that it can be effective, especially when considering the impact on a large scale (all students in a state or the entire country).

However the last line of the article was the most important to me:
"The switch [to lower-fat milk] also might promote changes in children's taste preferences toward lower-fat milk."
While I disagree with the premise that kids need 3 glasses of milk a day for "strong bones" - I do think that a kid who drinks several glasses of milk a day will be better off drinking lower-fat milk than whole milk. Just do the math:

A typical half-pint (8 oz) serving of whole milk has 146 calories and 8 grams of fat (5 are saturated fat). But a half-pint of 1% plain milk has only 102 calories and 2 grams of fat (1.5 are saturated).

Changing the types of milk offered in school does not appear to impact kids' consumption of this nutrient rich beverage. But it may serve to change norms and taste preferences for lower-fat milk, which could benefit them in the future. Schools are meant to teach our kids the skills and habits that will promote life-long learning, health, and success. The cafeteria is one place where greater attention to this educational mission is warranted.

Glad to have some evidence to back up this school policy. Make sure your school sells low-fat and/or fat-free milk!!

Note: the milk carton image was created by Mark A. Hicks, illustrator and published in Discovery Education's Clip Art Gallery.

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