What do some epilepsy patients have in common with tech bros, bodybuilders, and Joe Rogan? The high-fat, carb-shunning diet known as keto, whose history dates back much further than its 2010s rise to fame. In this episode, Gastropod traces how a medical treatment pioneered more than 2,500 years ago was refined in the 1920s to treat seizures. We trace its wild ride in and out of fashion, with cameos from Robert Atkins, the 80s exercise craze, and Meryl Streep. And, of course, we've got the myth-busting science on what ketosis and ketones really are, the dangers of eating this way to lose weight, and the reason this diet can be life-saving—for people with a very specific medical condition. Bust out the butter (but please don't put it in coffee) and join us down the keto rabbit hole.