Being pregnant was a lot like being a child again. There was always someone telling you what to do.
The basic idea that incentives can be used to motivate behavior is a powerful one. It works for employees, and it has a clear place in parenting, as anyone who has tried to potty-train a recalcitrant toddler with sticker rewards knows.
The greatest moments are those when you see the result pop up in a graph or in your statistics analysis - that moment you realise you know something no one else does and you get the pleasure of thinking about how to tell them.
Every time you have a carrot instead of a cookie, every time you go to the gym instead of going to the movies, that's a costly investment in your health. But how much you want to invest is going to depend on how much longer you expect to live in the future, even if you don't make those investments.
The key to good decision making is evaluating the available information - the data - and combining it with your own estimates of pluses and minuses. As an economist, I do this every day.