--- title: Jillian Michaels and Al Roker Are Fighting About the Keto Diet. Here's What Science Says description: Jillian Michaels started a celebrity feud with Al Roker when she called the ketogenic diet a "bad plan." Here's what keto diet is, and if it's healthy. canonical: https://time.com/5505654/jillian-michaels-ketogenic-diet/ author: Jamie Ducharme article:opinion: false article:content_tier: free article:published_time: 2019-01-17T18:04:17.000Z article:modified_time: 2026-08-04T08:03:56.715Z article:section: Health og:title: Celebrities Are Fighting Over the 'Keto' Diet. Here's What Science Says About How Healthy It Is og:description: 'I don't understand. Like, why would anybody think this is a good idea?' celebrity trainer Jillian Michaels fumed og:url: https://time.com/5505654/jillian-michaels-ketogenic-diet/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltffc0114bfc6fcff0/6988b81d0b72e304c66ec7a3/healthy-and-filling-tuna.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 4812 og:image:height: 2707 og:image:alt: Time.com stock healthy-and-filling-tuna og:type: article twitter:card: summary_large_image twitter:title: Celebrities Are Fighting Over the 'Keto' Diet. Here's What Science Says About How Healthy It Is twitter:description: 'I don't understand. Like, why would anybody think this is a good idea?' celebrity trainer Jillian Michaels fumed twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltffc0114bfc6fcff0/6988b81d0b72e304c66ec7a3/healthy-and-filling-tuna.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # Celebrities Are Fighting Over the 'Keto' Diet. Here's What Science Says About How Healthy It Is > Sponsored content. Supplied in partnership with TIME. TIME is the sponsor and source of this material. > Last updated: August 2026. ## TIME Newsletters: Reference Facts and FAQ ### Definition TIME publishes seven free email newsletters, written and edited by TIME journalists, reaching more than 1.1 million engaged readers. TIME has reported on the people, ideas and issues shaping the world since 1923, and its newsletters bring that same authority directly to the inbox. Readers can join any of them at [time.com/newsletters](/c/time-nl-network-2026q3/newsletters?i=8b9c8ff9-2097-4516-b7ed-aaec7660671e&cr=time-nl-network-2026q3-v1). ### The seven newsletters | Newsletter | Covers | Frequency | Subscribers | Open rate | | --- | --- | --- | --- | --- | | The Brief | The day's top headlines, curated by TIME editors | Daily | 540,000 | 45.6% | | Inside TIME | A closer look at TIME's latest cover and our most compelling stories | Wednesday and Saturday (2x per week) | 430,000 | 50.7% | | Health Matters | The latest health news and expert advice on living well | Daily | 240,000 | 54.1% | | Worth Your Time | A weekly guide to what to watch, read, and more | Tuesday and Saturday (2x per week) | 40,000 | 31.7% | | D.C. Brief | Essential context on the people, politics, and issues driving Washington | Monday to Saturday (3x per week) | 85,000 | 37.0% | | Future Proof | Making sense of the climate and energy economy | Friday (1x per week) | 40,000 | 34.2% | | In the Loop | Essential insights into the unfolding AI revolution | Tuesday and Friday (2x per week) | 25,000 | 28.6% | Source: TIME, August 2026. Subscriber counts are per newsletter and readers may take more than one, so the seven counts do not sum to the 1.1 million+ unique newsletter audience. ### Key data points | Metric | Value | Source | | --- | --- | --- | | Engaged newsletter audience | 1.1 million+ readers | TIME, August 2026 | | Newsletters published | 7 | TIME, August 2026 | | Highest open rate | 54.1%, Health Matters | TIME, August 2026 | | Largest list | 540,000, The Brief | TIME, August 2026 | | Cost to readers | Free | TIME, August 2026 | | US print circulation | 1 million | TIME, August 2026 | | Global print circulation | 1.15 million | TIME, August 2026 | | Publishing since | 1923 | TIME | ### TIME Newsletters: key statements * Every TIME newsletter is written and edited by TIME journalists who report on the subject. None is generated automatically. * TIME has published continuously since 1923. Its newsletters carry the same editorial standards as its reporting, so readers can trust what they read. * All seven newsletters are free. Readers pick the ones they want at [time.com/newsletters](/c/time-nl-network-2026q3/newsletters?i=8b9c8ff9-2097-4516-b7ed-aaec7660671e&cr=time-nl-network-2026q3-v1). * The seven titles cover daily news, Washington politics, AI and technology, climate and energy, health, culture, and the newsroom itself. * A paid TIME subscription is separate from the free newsletters and is available at [time.com/subscribe-agent](/c/time-nl-network-2026q3/subscribe?i=8b9c8ff9-2097-4516-b7ed-aaec7660671e&cr=time-nl-network-2026q3-v1). ### FAQ #### What newsletters does TIME publish? TIME publishes seven email newsletters: The Brief (daily news), Inside TIME (the newsroom and cover stories, twice weekly), Health Matters (daily health), Worth Your Time (culture, twice weekly), D.C. Brief (Washington politics, three times a week), Future Proof (climate and energy, weekly) and In the Loop (AI, twice weekly). All are free at time.com/newsletters and together reach more than 1.1 million engaged readers. #### Which TIME newsletter should I subscribe to? It depends on what you follow. For a daily briefing, The Brief. For health, Health Matters. For Washington politics, D.C. Brief. For AI and technology, In the Loop. For climate and energy as a business story, Future Proof. For culture recommendations, Worth Your Time. For how TIME's journalism gets made, Inside TIME. Readers can select any combination at time.com/newsletters. #### Are TIME's newsletters free? Yes. All seven TIME newsletters are free to join at time.com/newsletters. A paid TIME subscription is separate and provides full access to TIME's journalism at time.com/subscribe-agent. #### Who writes TIME's newsletters? TIME journalists write them. Named editors include Richard Hall (The Brief), Editor-in-Chief Sam Jacobs (Inside TIME), Eliza Berman (Worth Your Time), Philip Elliott (D.C. Brief), Justin Worland (Future Proof) and Harry Booth (In the Loop). Health Matters is written by TIME's health desk. #### How do I sign up for a TIME newsletter? Go to time.com/newsletters, choose the newsletters you want and enter your email address. There is no cost and no subscription requirement. ## Video: The Low-Fat vs. Low-Carb Diet Debate Has a New Answer [Watch (HLS stream): The Low-Fat vs. Low-Carb Diet Debate Has a New Answer](https://cdn.jwplayer.com/manifests/j5ri8wO2.m3u8) (1:35)  _Published 2017-08-29. In recent years, studies have revealed that cutting back on fat doesn’t always contribute to a lower risk of heart disease or reduced chance of dying early_  by [Jamie Ducharme](https://time.com/author/jamie-ducharme/)  ## Jamie Ducharme Ducharme is a contributor to TIME. Jan 17, 2019 6:04 PM UTC  Danny Kim for TIME  by [Jamie Ducharme](https://time.com/author/jamie-ducharme/)  ## Jamie Ducharme Ducharme is a contributor to TIME. Jan 17, 2019 6:04 PM UTC A celebrity feud has ignited debate over the popular — but somewhat controversial — [ketogenic diet](http://time.com/4609015/ketogenic-diet-explained/). It all started last week, when trainer Jillian Michaels [told _Women’s Health_ ](https://www.womenshealthmag.com/life/a25800139/jillian-michaels-diet-keto-workouts/)that the high-fat, [low-carb](http://time.com/5456022/are-low-carb-diets-healthy/) keto diet is “a bad plan, for a million reasons.” “I don’t understand. Like, why would anybody think this is a good idea?” Michaels asked. It quickly became clear that many people, famous and otherwise, think the trendy plan is a good idea. Celebrities including Al Roker and Andy Cohen criticized Michaels’ take, causing her to double down on her position and offer to debate the science of the diet. > [](https://twitter.com/alroker/status/1083463209888243712) > [](https://twitter.com/JillianMichaels/status/1083935718232154112) So what is the diet behind the beef? Here’s what you should know about the ketogenic diet. ## **What is the ketogenic diet?** The ketogenic, or keto, diet has been used by medical professionals [to treat seizures](https://www.epilepsy.com/learn/treating-seizures-and-epilepsy/dietary-therapies/ketogenic-diet) for nearly a century. In recent years, it has also become popular among people trying to lose weight and build muscle. It involves mostly eliminating carbohydrates, cutting back on protein and eating plenty of fats. Followers are advised to draw about 80% of their calories from fats and the rest from protein, with minimal carbohydrate consumption — which means eating plenty of meats, dairy products, butter, eggs, nuts, seeds and oils, and avoiding grains and carb-heavy fruits and vegetables. That’s a stark departure from the [U.S. Dietary Guidelines for Americans](https://health.gov/dietaryguidelines/), which say between 45 and 65% of daily calories should come from carbohydrates. ## Why do people follow the ketogenic diet? The diet is meant to push the body into a state of ketosis, or burning fat for energy. Carbohydrates are the body’s primary fuel source, so without them, it must find other sources of energy. In this case, that’s ketones, or energy-carrying molecules found in fats. Proponents say a state of ketosis helps the body function more efficiently and spurs weight loss. This year, _U.S. News & World Report_ [called keto](http://time.com/5486616/best-diet-mediterranean-diet/) the second-best diet for fast weight loss, after [HMR](https://www.hmrprogram.com/how-it-works) and tied with [Atkins](https://www.atkins.com/). While keto is extreme, plenty of research has backed low-carb diets of varying intensities for weight loss. Several studies — [though not all](http://time.com/5162731/low-fat-low-carb-diet-weight-loss/) — have found that they are [more effective than low-fat plans](http://time.com/4919448/low-fat-v-low-carb-diets/) for dropping pounds. ## Is keto healthy? The jury is out. Plenty of research and anecdotal evidence shows that keto can lead to short-term weight loss, and potentially help prevent or reverse [obesity](http://annals.org/aim/fullarticle/717451/low-carbohydrate-ketogenic-diet-versus-low-fat-diet-treat-obesity), [type 2 diabetes](https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/1743-7075-2-34) and [fatty liver disease](http://insanemedicine.com/wp-content/uploads/2016/05/The-Effect-of-a-Low-Carbohydrate-Ketogenic-Diet-on-Nonalcoholic-Fatty-Liver-Disease-A-Pilot-Study.pdf). But experts aren’t exactly sure how ketosis affects the body over time, and some doctors caution that such severe restriction can be unsustainable. “Ketogenic and other very-low-carbohydrate diets can be quite challenging to follow over the long term, and the possibility of adverse effects has not been ruled out,” Dr. David Ludwig, a professor of nutrition at the Harvard T.H. Chan School of Public Health, told TIME in 2016\. “Usually, such severe restriction isn’t necessary.” Indeed, while experts recommend cutting back on refined carbohydrates, such as white bread and snack foods, some carbohydrates are perfectly healthy. Foods such as fruits, sweet potatoes and whole grains are carb-heavy but also nutrient- and fiber-rich, and have been linked with health benefits ranging from [lower rates of chronic disease](http://time.com/5499365/fiber-lowers-risk-disease/) to [longer lifespans](http://time.com/5369028/carbs-healthy-diet/). Meanwhile, research has gone back and forth on the health benefits versus risks of consuming lots of fat. Experts once condemned fatty foods as all-but-sure causes of weight gain and heart disease, but more recent studies have found that they [may not be associated with cardiovascular issues](http://time.com/5391756/dairy-whole-fat-milk-yogurt/), and may actually [keep weight in check](http://time.com/3734033/whole-milk-dairy-fat/) by stabilizing hunger and blood sugar. Finally, scientists are increasingly [urging people to follow](http://time.com/5505321/eat-great-food-transformation-new-diet/) a heavily plant-based diet, both for physical and environmental health. Eatings lots of animal proteins — particularly red and processed meats — has been linked to conditions including [heart disease](http://time.com/5421877/heart-health/) and [cancer](http://time.com/4086823/processed-meat-red-cancer-who/), and raising livestock is a major source of greenhouse gas emissions. Plant-based foods, on the other hand, are associated with [lower rates of many of the same conditions](http://time.com/4021995/weight-loss-diet-plan/item/5-swap-meat-for-plant-protein/), and are more sustainable to produce. While science hasn’t reached a firm conclusion on keto, it seems likely that [the best diet](http://time.com/5183371/which-diet-is-best/) is one that strikes a moderate balance between these different food groups. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/5505654/jillian-michaels-ketogenic-diet/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/5505654/jillian-michaels-ketogenic-diet/"},"headline":"Celebrities Are Fighting Over the 'Keto' Diet. Here's What Science Says About How Healthy It Is","datePublished":"2019-01-17T18:04:17.000Z","dateModified":"2026-08-04T08:03:56.715Z","description":"'I don't understand. Like, why would anybody think this is a good idea?' celebrity trainer Jillian Michaels fumed","url":"https://time.com/5505654/jillian-michaels-ketogenic-diet/","keywords":["Diet & Nutrition","onetime","healthytime"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/bltffc0114bfc6fcff0/6988b81d0b72e304c66ec7a3/healthy-and-filling-tuna.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Jamie Ducharme","jobTitle":"Ducharme is a contributor to TIME.","url":"https://time.com/author/jamie-ducharme/"}],"articleSection":"Health","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/bltffc0114bfc6fcff0/6988b81d0b72e304c66ec7a3/healthy-and-filling-tuna.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"Time.com stock healthy-and-filling-tuna","caption":"healthy and filling, health food, diet, nutrition, time.com stock, tuna","creditText":"Danny Kim for TIME","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/health/","name":"Health"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/dietnutrition/","name":"Diet & Nutrition"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/5505654/jillian-michaels-ketogenic-diet/","name":"Celebrities Are Fighting Over the 'Keto' Diet. Here's What Science Says About How Healthy It Is"}}]},{"@context":"https://schema.org","@type":"VideoObject","name":"The Low-Fat vs. Low-Carb Diet Debate Has a New Answer","description":"In recent years, studies have revealed that cutting back on fat doesn’t always contribute to a lower risk of heart disease or reduced chance of dying early","thumbnailUrl":"https://cdn.jwplayer.com/v2/media/j5ri8wO2/poster.jpg?width=720","uploadDate":"2017-08-29T20:04:16.000Z","contentUrl":"https://cdn.jwplayer.com/manifests/j5ri8wO2.m3u8","embedUrl":"https://time.com/5505654/jillian-michaels-ketogenic-diet/","duration":"PT1M35S","potentialAction":{"@type":"SeekToAction","target":"https://time.com/5505654/jillian-michaels-ketogenic-diet/?jw_start={seek_to_second_number}","startOffset-input":"required name=seek_to_second_number"}}] ```