While eating breakfast tacos at our heavenly neighborhood taqueria, Gueros, this weekend, I began to muse on fat. After all, I could think of many reasons why the tacos were delicious (The tang of those pickled onion! The salt of that queso fresco! The bite of that habanera sauce!), but the plain tortilla chips were just as irresistible, and I had a feeling that it was because of the sheen of glistening oil that they wore after their bath in the deep fryer.

I formed an extemporaneous theory that this must be because of some evolutionary phenomenon. After all, it’s not that fat is bad, necessarily, just that it packs a huge wallop of calories and energy all at once, which was probably quite helpful if you were trying to, say, survive a famine. Jason was skeptical of this thinking—if fat was actually good, then why did his stomach feel so lousy after eating all that grease? If he had stalked a wooly tortilla chip across the icy tundra for four days, I retorted, his stomach would probably feel just fine.

While little information is available about the elusive wild tortilla chip, I did find some interesting evidence that scientific thought about fat is still evolving. Continue reading →