Actually, there is a good reason to believe that natural flavours that taste good to us do so because they're healthy and contain the correct nutrients for us, and our bodies even can know about when we've consumed enough of them.

This book outlines all of that http://www.amazon.ca/Dorito-Effect-Surprising-Truth-Flavor/d...

If you don't want to read the whole book, here's the audio from a program called The Agenda with Steve Paikin with the author of The Dorito Effect. http://podcasts.tvo.org/theagenda/audio/2301343_48k.mp3