Schools from coast to coast are swapping greasy lunch meals, like nachos, for healthy ones, like broccoli casserole. Experts say that instead of eating healthier, kids are now eating more junk than before, mostly buying sugary snacks like cookies and candy from the school vending machines. Why? Because kids have been eating unhealthy food for years, and are jolted when seemingly overnight their favorite foods are replaced with 100% all-natural food. A lot of them hate the taste and say it has no flavor, and assume all healthy food is disgusting.

That’s exactly what’s happening at Chicago Public Schools. Their cafeterias recently stopped serving Pop Tarts and doughnuts, and replaced them with fruit and oatmeal. The result? They’re selling 20,000 fewer lunches a day, and the number’s continuing to plummet. Even worse, all schools depend on booming lunch sales to fund their cafeteria operations. If students aren’t buying healthy food, then they could be forced to close their doors and not offer anything.

In fact, the Chicago Public Schools are so desperate to boost sales, they recently brought back an unhealthy but favorite meal of students: A processed spicy chicken patty sandwich. Doctors warn that schools can’t cave in to students’ unhealthy appetites. So, schools are scrambling to hook students with healthy food. How? Not by spicing up the meals, but by spicing up their marketing campaigns. Dr. Brian Wansink is a Cornell University professor who specializes in eating behavior. He says the key to making it work is to use basic psychology. For example, studies show a 35% jump in healthy food consumption when nutritious items are given fun names like "big bad bean burrito." Also, healthy food is often more appealing when it’s at the front of a lunch line, because most people instinctively grab the first food items they see.