The Obesity Code: Unlocking the Secrets of Weight Loss by Jason Fung cover

The Obesity Code: Unlocking the Secrets of Weight Loss

by Jason Fung

$5.36 on AmazonRead our full review

At a glance

Pages296
First published2016
AudienceAdult
ISBN1771641258

About the Author

Jason Fung

2 books reviewed

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LuvemBooks Verdict

Best for

Motivated general readers who feel let down by conventional dieting advice and want a systematic, physician-authored hormonal framework for understanding weight gain, presented with clinical references but without specialist jargon.

Worth it if

You're willing to follow an extended, multi-part argument — from epidemiological history through to practical guidance — and appreciate a coherent alternative theory of obesity even if it sits outside mainstream scientific consensus.

Skip if

You need a book whose recommendations reflect broad clinical consensus, or you're already familiar with the research literature and want a balanced survey of competing obesity models rather than one persuasively argued position.

What readers & critics say

Diagnosis Diet praises Fung's writing for striking "just the right balance" between clinical rigour and general readability, calling it a crossover success that convinces sceptical physicians without overwhelming lay readers. Red Pen Reviews, however, awards the book a modest scientific accuracy score, finding that its three core claims are poorly supported or exaggerated and that the carbohydrate-insulin model, while real, is a minority view "not well-enough established to warrant the strong claims" Fung makes.

Sources: Diagnosis Diet, Red Pen Reviews
4.6from 37,970 Amazon ratings— reader ratings, not a LuvemBooks score

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The Obesity Code: Unlocking the Secrets of Weight Loss by Dr. Jason Fung argues that obesity is a hormonal disorder driven by chronically elevated insulin levels — not a failure of willpower or caloric arithmetic — and that intermittent fasting is a primary tool for correcting it. Praised by Diagnosis Diet for striking "just the right balance" between clinical rigor and readability, the book is one of the more substantive entries in popular nutrition literature for general readers who feel conventional dieting advice has failed them. The key caveat: the carbohydrate-insulin model Fung champions is a minority scientific view, and the book's confident tone can make contested hypotheses read as settled consensus, a concern raised explicitly by Red Pen Reviews.
Is it worth reading?
For readers who feel that conventional dieting advice has failed them, The Obesity Code offers a coherent, physician-authored alternative framework that goes well beyond simplistic 'eat less, move more' guidance. Its six-part structure rewards readers willing to follow an extended argument across multiple sections, and its combination of accessible writing, referenced sourcing, and a systematic hormonal theory of weight gain makes it a substantive entry in popular nutrition literature. Those who already follow the research literature should note that Red Pen Reviews characterizes Fung's carbohydrate-insulin model as a minority view, and the book is best read alongside sources representing the full range of scientific opinion.
Similar books
Readers drawn to The Obesity Code will find natural companions in The Complete Guide to Fasting by Dr. Jason Fung and Jimmy Moore, which expands directly on the intermittent fasting framework introduced here. Good Energy by Casey Means MD and Calley Means similarly challenges mainstream metabolic health assumptions, while Outlive by Peter Attia MD engages with longevity, metabolism, and preventive medicine from a rigorous physician-authored perspective. For a contrasting dietary philosophy, How Not to Diet by Michael Greger MD FACLM or The China Study by T. Colin Campbell and Thomas M. Campbell offer well-documented alternative frameworks. Salt Sugar Fat by Michael Moss and In Defense of Food by Michael Pollan round out the broader conversation about how the food environment has shaped health outcomes.
Who should read this?
The Obesity Code is best suited to motivated general readers who feel that conventional dieting advice has repeatedly failed them and who want a systematic, physician-authored explanation for why. Its six-part structure rewards readers willing to work through an extended argument rather than skip to a meal plan. Readers already familiar with the research literature on obesity and metabolic health will recognize Fung's thesis as one significant position in an ongoing scientific debate, and may want supplementary reading. Those seeking recommendations that reflect broad clinical consensus may find the book a provocative but incomplete picture.
About Jason Fung
Peter Daou is a Lebanese-American political activist, musician, and author.
How does this compare to The Complete Guide to Fasting?
The Obesity Code functions as the theoretical foundation, building the hormonal case for why intermittent fasting works by establishing the insulin-driven model of obesity from the ground up. The Complete Guide to Fasting, co-authored by Dr. Jason Fung and Jimmy Moore, moves further into practical protocols and implementation. Readers looking for the 'why' behind fasting will find The Obesity Code the more essential starting point; those already persuaded and seeking the 'how' may find The Complete Guide to Fasting more immediately actionable.
How scientifically credible is it?
The Obesity Code is a referenced, evidence-cited argument written by a practicing nephrologist, and it draws on real research aligned with the carbohydrate-insulin model also associated with obesity researcher David Ludwig, MD, PhD. However, Red Pen Reviews — which subjects nutrition books to structured scientific scrutiny — concludes that while some researchers accept insulin as a primary driver of obesity, it is 'a minority view that is hard to reconcile with the evidence as a whole,' and that the theory is 'not well-enough established to warrant the strong claims' Fung makes. The book's persuasive clarity can make contested hypotheses read as settled consensus, so readers are best served by treating it as one well-argued position in an active scientific debate.
Summarize this book

Summarize this book

Published by Greystone Books in March 2016, The Obesity Code is a science-grounded non-fiction guide in which practicing nephrologist Dr. Jason Fung dismantles the conventional 'calories in, calories out' model and proposes that obesity is fundamentally a hormonal disorder caused by persistently high insulin levels and insulin resistance. The book is organized into six parts, moving from the history of the obesity epidemic through a refutation of entrenched nutritional myths — including the idea that dietary fat causes weight gain — and into Fung's proposed hormonal framework and practical guidance centered on intermittent fasting. It includes bibliographical references and an index, and carries a foreword by Timothy Noakes.

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Age & Reading Level

Recommended age

Adult

Reading level

Adult

Skip if you want dietary recommendations that reflect broad clinical consensus rather than a minority scientific model.

Editorial Review

Published by Greystone Books in 2016, The Obesity Code: Unlocking the Secrets of Weight Loss is a science-based non-fiction guide by practicing physician and New York Times-bestselling author Dr. Jason Fung, with a foreword by Timothy Noakes. Fung's central argument rejects the conventional "calories in, calories out" model, proposing instead that obesity is a hormonal disorder driven by persistently high insulin levels and insulin resistance — and that intermittent fasting is a key lever for correcting it. The book is structured across six parts, moving from the history of the obesity epidemic through a dismantling of what Fung calls nutritional "myths," and into his proposed hormonal model and practical framework. It is a landmark title in the low-carbohydrate and intermittent-fasting conversation, though its core thesis sits at the contested edge of nutrition science.

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