In this week’s Health newsletter, we examine three things that may lengthen your life: so-called good fat, a form of fasting, and protecting your gut—particularly over the holiday season. Plus, mixing vitamins and minerals; a cannabis caution.

PHOTOGRAPH BY FROGGY/GROGG, ISTOCK/GETTY IMAGES PLUS 

And it can keep us young, too? Research suggests that brown fat—which we lose as we age—might reduce the risk of inflammatory diseases, control obesity, and ultimately lengthen our lives.

PHOTOGRAPH BY JASPER DOEST 

Yeah yeah yeah: Fasting is a popular practice, and research shows it has real health benefits. A new diet—which tricks your body into thinking it’s fasting—may have similar benefits.

Related: Giving up alcohol can do your body a world of good 

Also: Sugar, too. And quickly.

PHOTOGRAPH BY STEVE GSCHMEISSNER, SCIENCE PHOTO LIBRARY 

PHOTOGRAPH BY THOMAS ERNSTING, LAIF/REDUX 

We know her as Lucy. Discovered a half-century ago, she didn’t challenge notions that humans began in Africa—or that their ancestors learned to walk upright before they developed bigger brains. What made Lucy such a cultural sensation?

A. She had a relatable nickname.
B. She was older than other remains found previously.
C. She was more complete than other ancient skeletons at the time.
D. She had a tireless and telegenic discoverer.
E. All of the above. 

Today’s Soundtrack: Who’s To Blame For The Narcolepsy? Koshi Inaba

Today’s newsletter was edited and curated by David Beard and Setota Hailemariam and produced by Amanda Bryant-Williams. Thanks for reading! Have a suggestion? Let us know.