Would You Put Butter in Your Coffee?

“It makes for the creamiest, most satisfying cup of coffee you’ve ever had,” Dave Asprey writes on his website. He’s the creator of Bulletproof Coffee, the small company credited for popularizing the concoction. The tech-investor attributes a high-fat diet to his 80-pound weight loss. And beyond taste, Asprey says this buttery drink provides all of the energizing benefits of a cup of coffee, without the four o’clock slump. Bulletproof believers insist that the butter’s high-fat content will slow the time it takes for your body to metabolize the coffee’s caffeine. In other words, increased energy, decreased crash.