Food nipples were first used 50000 years ago, when the grunts of the time, were on a food shortage. When the food shortage ended, the grunts already preferred the taste of the food nipples, and decided to use it as their primary food source.
Other species claims the food nipples taste like different things. Elites claims it tastes like blueberry pie. Humans claims it tastes like a weird, but an arousing mixture of chocolate milk, and nachos.