“When they have the debit card rather than the cash, we know that it causes them to think about it slightly differently,” says David Just, PhD, lead study author and professor at the Cornell Center for Behavioral Economics in Child Nutrition Programs. Debit cards give kids access to a pool of funds—$150 at once, let’s say, instead of the daily $5 that parents might give them for lunch. That leaves a lot of room to purchase more unhealthy à la carte items like cookies and chips.
Among the 2,314 public school students studied, the differences between the debit vs. cash crowd were stark. At schools that allowed cash purchases, 42% of students chose healthy items, while only 31% of kids at debit-only schools bought them. Kids at cash-friendly schools bought 20% more fresh vegetables and less candy than kids at debit-only schools, and they ate an average of 31 fewer calories than their debit peers.
Debit cards certainly have their place in cafeterias—they expedite lunch lines, which gives kids more much-needed time to eat, and they ensure that kids on a free or reduced-lunch program aren’t singled out. But the health consequences are significant, especially as more schools go cashless. One solution? Some schools partner with debit vendors that allow parents to put parental controls on how much money their kids can spend each day, or even on what they’re allowed to buy, Dr. Just says.
But kids aren’t the only ones due for a debit detox. Studies have shown that credit-card-wielding adults spend more money on more frivolous things—pleasurable things higher in sugar, fat, and salt—than they do when they spend cash.
Some credit card companies offer features that allow users to set spending limits on certain categories—a budget specifically for fast-food restaurants, for instance. But until the diet credit card becomes a reality, there’s a simple change you can make, Dr. Just says. “Restricting yourself to cash for food purchases really would change the types of food you eat.”
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