The Obesity Code
Dr. Jason Fung · 2016 · 10 ideas · 10 min
Obesity isn't a calorie-counting failure but a hormonal disorder — driven chiefly by chronically high insulin — and the fix is when you eat, not just how much.
Why this book
Fung's argument starts with a simple observation: if obesity were really just "calories in, calories out," fifty years of counting calories should have worked. It hasn't. He proposes that fat storage is governed by hormones, above all insulin, and that the modern diet — frequent meals, refined carbohydrates, snacking around the clock — keeps insulin chronically elevated, which locks the body into fat-storage mode regardless of willpower. Cutting calories without lowering insulin, he argues, just makes the body defend its fat harder, which is why diets stall.
Why it matters: the book reframes weight loss from a math problem into a hormonal one, which changes the intervention from eat less to eat less often and eat differently — mainly through intermittent fasting, which Fung positions as the most direct lever on insulin available without drugs.
Who should read it
Anyone who has lost weight on a diet only to watch it return, and who suspects the standard advice is missing something, will find this book's hormonal reframing clarifying. It's also useful for people newly curious about intermittent fasting who want the physiological case for it, not just the anecdotes.
About the author
Jason Fung is a Toronto-based nephrologist who, after years of treating diabetic patients with worsening kidney disease, became a leading clinical voice on therapeutic fasting and low-carbohydrate approaches to obesity and type 2 diabetes.