Broccoli is nutritious, and it knows it.
Since humans and other plant-eating animals have reason to consume a lot of broccoli, it has come to produce goitrin, a compound that tastes very bitter to people with a certain gene—which serves as a (meager) defense against getting eaten. Other vegetables that come from the very same plant, including kale, brussels sprouts, and collard greens, all employ a similar protective strategy. But, as the podcast Surprisingly Awesome recently noted, broccoli’s flavor armor can be actually quite effective, as evidenced by many kids’ disgusted reaction to tasting it for the first time.
But those kids can learn to like it, eventually: One 1990 study found that kids need to be presented with unknown foods somewhere between eight and 15 times before they come to accept them. This, of course, doesn’t come cheap. Once rejected, a good number of those eight to 15 servings of broccoli (or carrots or whole grains or fish) are going to end up on the floor and then in the garbage. And on top of that, parents need to buy a dependable backup food to have on hand.
Who can afford that sort of waste? Not parents with tight food budgets. A recently published study looking into the eating and shopping habits of both low-income and high-income parents suggests that the steep up-front cost of introducing foods to children is enough to deter a number of parents from trying. This cost-cutting decision may explain some of the differences between how rich and poor Americans eat.