Keto has been promoted as a magic bullet for weight loss by its supporters and slammed as dangerous by its opponents. It's no surprise - completely removing almost all carbohydrates is not what most people consider ‘a balanced diet’. With carbs off the table, Keto diets involve a dramatically increased fat intake. At the same time, drastically reducing carbs means starving our gut microbes of the fiber that feeds them.  Nonetheless, doctors prescribe keto diets to treat people with severe diabetes and see dramatic improvements, and many healthy people swear by keto for weight loss. On top of this, removing carbohydrates prevents blood sugar spikes and crashes linked to inflammation and disease.  In today’s episode, Jonathan speaks to a leading nutritional researcher to understand whether or not keto diets are a crazy fad: Christopher Gardner is a professor at Stanford University and a member of ZOE’s scientific advisory board who’s produced a clinical trial of keto diets, published in the American Journal of Clinical Nutrition. Download our FREE guide — Top 10 Tips to Live Healthier: https://zoe.com/freeguide Timecodes: 00:00 - Intro 00:10 - Topic introduction 01:38 - Quick-fire questions 05:20 - What is a ketogenic diet? How does it work? 08:34 - Why have people become interested in keto? 10:16 - To promote ketosis, how low-carb should a diet be? 11:46 - Why are randomized trials so important? 14:37 - Christopher’s study 18:46 - What is a Mediterranean diet? 21:31 - Study results 25:33 - How sustainable is a keto diet? 31:22 - How strictly should you follow the keto diet? 32:47 - Diabetes and keto 35:36 - Keto’s impact on the microbiome 37:57 - Is there a long-term impact on the ability to process carbs? 39:51 - Summary 41:40 - Listener’s question 42:12 - Goodbyes 42:32 - Outro Episode transcripts are available here. Read Chris’ Study here. Follow Chris: https://twitter.com/GardnerPhD Follow ZOE on Instagram: https://www.instagram.com/zoe/ This podcast was produced by Fascinate Productions.