It doesn’t mean extravagant, it means “a lot of food to eat”. I know how to cook. The intuition of how much I need to cook comes with more experience, but it means I’d need to go through months of me cooking too much and either throwing it away, or eating the same thing for a long time. When you cook for two or more, the dishes just disappear. You can skip a day, your partner will eat it though. So then you do, and suddenly four days worth of meals are gone.