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FROM NEW YORK TIMES BESTSELLING AUTHOR DR. JASON FUNG—the physician widely credited with popularizing intermittent fasting for weight loss—comes the landmark book that is helping millions around the world achieve natural, sustainable weight loss.

The Obesity Code is a groundbreaking, science-based guide to lasting weight loss that goes beyond “calories in, calories out.” Instead of blaming lack of willpower, practicing physician Dr. Fung explains how hormones—especially insulin—drive weight gain, cravings, and stubborn belly fat. If you’ve tried countless diets and always regain the weight, this book shows you why, and what to do differently.

Drawing on clinical research and real patient success stories, The Obesity Code reveals how insulin resistance and constantly elevated insulin levels lock your body into fat-storage mode. Traditional low‑fat diets, frequent snacking, and severe calorie restriction can actually make things worse, slowing your metabolism and increasing hunger. Dr. Fung shows you how to work with your biology instead of against it, so you can lose weight naturally and improve your metabolic health.

Dr. Fung is often cited as the founder of intermittent fasting for weight loss. Rather than another restrictive fad, intermittent fasting is a flexible, practical tool you can adapt to your lifestyle. You’ll learn:
How intermittent fasting helps lower insulin and unlock stored fatDifferent fasting methods (including 16:8, 24‑hour fasts, and more)How to start safely and manage hunger, social events, and busy days
In addition to when you eat, Dr. Fung explains what to eat for sustainable, natural weight loss. The Obesity Code emphasizes:
Whole, unprocessed foods instead of ultra‑processed snacksMinimizing sugar and refined carbohydrates that spike insulinIncluding healthy fats, quality protein, and fiber‑rich vegetablesA realistic, adaptable approach rather than a rigid, one‑size‑fits‑all diet
Whether your goal is to lose weight, reduce belly fat, reverse pre‑diabetes or type 2 diabetes, or simply improve overall health and wellness, The Obesity Code provides clear explanations and actionable steps. It’s ideal for readers who want to:
Lose weight naturallyLearn how to intermittent fast for weight lossReverse insulin resistanceGain science-backed weight loss information
If you’re tired of yo‑yo dieting, conflicting diet advice, and short‑term fixes, The Obesity Code offers a clear, evidence‑based roadmap to lasting change. Learn how to rebalance your hormones, use intermittent fasting effectively, and finally achieve the healthy, sustainable weight loss you’ve been looking for.

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Dr. Jason Fung, MD

Dr. Fung is the New York Times bestselling author of multiple critically acclaimed science and health books. He completed medical school at the University of Toronto and a fellowship in nephrology at Stanford University, and is now a practicing nephrologist (kidney doctor) and co-founder of The Fasting Method, a program to help people lose weight and reverse type 2 diabetes and obesity.

Publisher ‏ : ‎ Greystone Books
Publication date ‏ : ‎ March 1, 2016
Edition ‏ : ‎ 1st
Language ‏ : ‎ English
Print length ‏ : ‎ 296 pages
ISBN-10 ‏ : ‎ 1771641258
ISBN-13 ‏ : ‎ 978-1771641258
Item Weight ‏ : ‎ 2.31 pounds
Dimensions ‏ : ‎ 5.9 x 1.2 x 8.9 inches
Book 1 of 2 ‏ : ‎ The Obesity Code
Best Sellers Rank: #2,934 in Books (See Top 100 in Books) #2 in Health, Mind & Body Reference #2 in Endocrinology & Metabolism (Books) #6 in Weight Loss Diets (Books)
Customer Reviews: 4.6 4.6 out of 5 stars (38,071) var dpAcrHasRegisteredArcLinkClickAction; P.when(‘A’, ‘ready’).execute(function(A) { if (dpAcrHasRegisteredArcLinkClickAction !== true) { dpAcrHasRegisteredArcLinkClickAction = true; A.declarative( ‘acrLink-click-metrics’, ‘click’, { “allowLinkDefault”: true }, function (event) { if (window.ue) { ue.count(“acrLinkClickCount”, (ue.count(“acrLinkClickCount”) || 0) + 1); } } ); } }); P.when(‘A’, ‘cf’).execute(function(A) { A.declarative(‘acrStarsLink-click-metrics’, ‘click’, { “allowLinkDefault” : true }, function(event){ if(window.ue) { ue.count(“acrStarsLinkWithPopoverClickCount”, (ue.count(“acrStarsLinkWithPopoverClickCount”) || 0) + 1); } }); });
Customers find this book to be a must-read that is well-documented and makes medical information understandable. Moreover, the book is easy to read with user-friendly terms, and customers appreciate its profound research and solid scientific basis. Additionally, they value its content on weight loss, explaining the science behind weight gain and offering alternate ways to lose weight, while also providing good guidelines on how to eat healthy. Customers describe it as life-changing, with one noting it changed their whole outlook, and they appreciate its focus on improving health and preventing debilitating metabolic diseases.