My sons’ schools allow parents to set up debit accounts for students to buy school lunch in the cafeteria. Parents can put money in the account online, and then they don’t have to worry about sending in money. I don’t put money in my sons’ accounts because there is no way to monitor how much they spend. If there is $20 in an account, a student could theoretically buy $20 worth of food at one lunch.

To me, it seemed like it would be too tempting for the boys to buy the regular lunch option and then load their tray up with cookies and chips, too, if I used the account option. So, on the two days a month that I allow them to buy, I send them with cash.

A recent study gives me another reason to think my cash-only policy is a wise one. NPR reports that according to behavioral economist Brian Wansink at Cornell University “kids are much, much, much more likely to take desserts and are much less likely to take fruits and vegetables" when they buy their lunches using a debit card or account than they are when they pay cash.

When students paid with cash, they bought three times as many vegetables and ate 10 percent fewer calories than when they paid with a debit. Why?

It probably has to do with the psychological effect of paying with credit or debit than with cash. Just like people choose to spend their money more wisely when shopping if they pay with paper rather than plastic, it seems as if students equate cash with making wiser choices.

In the past couple of years, the schools in my district have highly encouraged parents to use the account system because it makes things move more quickly in the lunchroom. When students have to dig cash out of their pockets and lunch aides have to make change, it can slow the long lines down. When lunch is only 23 minutes long, every second counts.

I understand that’s an issue, but I’m still going to continue to send in cash. The twice-a-month school lunch that my kids buy is a compromise. I’m not willing to compromise any more on this.

If you have kids who buy lunch at school regularly or just once in a while, do you use a debit system or have them pay with cash? Do the findings in this study make you think differently about the way they pay?

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Robin Shreeves ( @rshreeves ) focuses on food from a family perspective from her home base in New Jersey.

Kids make healthier cafeteria choices when paying cash, study says
Cash in hand is an incentive for students to chose more fresh produce.