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How Not to Diet by Michael Greger M.D. FACLM Review: Science-Driven Weight Loss Beyond Fad Diets
A New York Times bestseller from the founder of NutritionFacts.org, How Not to Diet dismantles the diet-fad cycle by grounding weight loss in peer-reviewed nutritional science, making a research-dense case for plant-based eating, calorie density, gut microbiome health, and twenty-one evidence-based fat-burning accelerators — a serious, wide-ranging reference for readers willing to engage with the depth of the science.
LuvemBooks Verdict
Best for
Chronic dieters who have cycled through trending approaches without lasting results and want a rigorous, evidence-based explanation of why those approaches fail — and what the science actually supports instead.
Worth it if
You want to understand the mechanisms behind weight loss — calorie density, the insulin index, gut microbiome, chronobiology — rather than simply follow a prescriptive meal plan, and you are open to a plant-based dietary framework backed by dense research citations.
Skip if
You are looking for a concise, quick-start protocol, are firmly committed to a ketogenic or other non-plant-based eating pattern, or find 608 pages of research-heavy reading more exhaustive than you need.
What readers & critics say
Books Google's snippet quotes critical coverage calling it a book "for those who want the facts, not your typical fantasy, filler or fluff," signalling strong praise from at least one major press outlet. The publisher page at us.macmillan.com highlights a peer endorsement from Dean Ornish, M.D., who describes it as "one of the best books I've ever read on how to lose weight in sustainable ways that enhance health."
Sources: Google Books, Macmillan4.7from 7,184 Amazon ratings— reader ratings, not a LuvemBooks score
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How Not to Diet is a 608-page, peer-reviewed deep dive into the science of sustainable weight loss, authored by physician and NutritionFacts.org founder Michael Greger M.D. — a serious reference work that goes far beyond food rules to cover calorie density, the insulin index, gut microbiome health, chronobiology, and twenty-one evidence-based fat-burning accelerators. It debuted as an instant New York Times Best Seller and earned a notable endorsement from Dean Ornish, M.D., signaling genuine credibility within evidence-based medicine. LuvemBooks considers it essential reading for anyone who wants to understand the "why" behind weight management, with the key caveat that its plant-based framework and research-heavy depth make it a demanding fit for readers seeking a quick, protocol-driven guide.
- Is it worth reading?
- For readers who have cycled through trending diets without lasting success and want to understand the underlying science, LuvemBooks considers How Not to Diet a genuinely authoritative resource. Its scope is unusually wide — ranging across calorie density, hormonal response, microbiome science, circadian biology, and sleep research — and every topic is grounded in citations to research rather than anecdote. The book's comprehensiveness is also its main barrier: at 608 pages, it rewards the committed reader far more than the reader seeking a concise, step-by-step protocol. Those open to engaging with the depth of the science, and at least willing to consider a plant-based dietary framework, will find it a reference that rewards re-reading.
- Similar books
- Readers drawn to How Not to Diet will find natural companions in several works featured on this page. Greger's own How Not to Die (not currently in the LuvemBooks catalogue) established his evidence-based, plant-forward framework, while The How Not to Die Cookbook (Greger and Gene Stone) translates that philosophy into recipes. T. Colin Campbell and Thomas M. Campbell's The China Study is one of the most cited works underpinning the plant-based dietary case. For a different angle on weight and metabolism, Jason Fung's The Obesity Code focuses on insulin and intermittent fasting — a direct counterpoint to some of Greger's conclusions. Michael Pollan's In Defense of Food offers a more accessible, less research-dense argument for whole-food eating, and Peter Attia's Outlive covers longevity science with comparable scientific rigor from a different dietary perspective.
- Who should read this?
- How Not to Diet is best suited to adult readers who have grown frustrated with cycling through diet trends and want a rigorous, evidence-grounded explanation of why those approaches succeed or fail. It rewards those who want to understand the mechanisms behind weight management — calorie density, the insulin index, microbiome health, chronobiology — rather than simply follow a protocol. Readers who are open to a plant-based dietary orientation, or at least willing to engage with the evidence for it, will find the framework most directly applicable. It is less well suited to readers seeking a quick-start guide, a minimalist plan, or a framework compatible with ketogenic or other animal-product-centered diets.
- About Michael Greger M.D. FACLM
- Michael Herschel Greger is an American physician, author, and speaker on public health issues. He is best known for his advocacy of a whole-food, plant-based diet and his opposition to animal-derived food products.
- Does the book push a plant-based agenda?
- Greger is explicit that plant-based eating is not one option among many in his framework but a scientifically grounded foundation for sustainable weight management — so yes, the book's dietary direction is clearly plant-based. However, the review draws a distinction between advocacy and dogma: rather than prescribing a rigid meal plan, Greger identifies the criteria that make a diet effective, inviting readers to reason about food choices rather than follow rules blindly. The book also directly engages with and evaluates competing approaches — including ketogenic diets and intermittent fasting — rather than dismissing them without argument. Readers committed to animal-product-centered eating patterns should go in knowing the evidence is marshalled in a specific direction.
- How does this compare to How Not to Die?
- How Not to Die established Greger's evidence-based, plant-forward method and applied it broadly to preventing disease across multiple organ systems. How Not to Diet is a more focused successor, applying the same research-intensive approach to a single question: what does the evidence say about healthy, permanent weight loss. At 608 pages, How Not to Diet is arguably denser and more exhaustive in its treatment of that narrower topic, and it adds new territory — chronobiology, twenty-one weight-loss accelerators, detailed engagement with competing diet philosophies — that goes beyond what How Not to Die covered. Both books share the same authorial philosophy and citation-heavy style.
Summarize this book
Is it worth reading?
Who should read this?
About Michael Greger M.D. FACLM
Does the book push a plant-based agenda?
How does this compare to How Not to Die?
Summarize this book
Published by Flatiron Books in December 2019, How Not to Diet is a science-focused nutrition reference book in which physician Michael Greger M.D. asks what peer-reviewed evidence actually says about healthy, permanent weight loss. The book moves through three broad sections: the root causes and mechanisms of obesity; a detailed framework for an ideal weight-loss diet built around calorie density, the insulin index, and gut microbiome health; and a final section that evaluates contested approaches including ketogenic diets, intermittent fasting, and high-intensity interval training. Greger also introduces twenty-one "weight-loss accelerators" — adjunct strategies drawn from fields including chronobiology — designed to work in concert with a solid dietary foundation, not as shortcuts around one. The publisher describes it as structured to be "timeless" and capable of standing up to any future diet trend.
Follow up
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Age & Reading Level
Recommended age
Adult
Reading level
Adult
who it suits
Skip if you want a concise, step-by-step weight-loss protocol rather than a deep engagement with nutritional science.
Our Review
Dr. Michael Greger's How Not to Diet belongs on the shelf of anyone who has cycled through trending diets without lasting success — and wants to understand why.
What the Book Actually Is
How Not to Diet: The Groundbreaking Science of Healthy, Permanent Weight Loss by Michael Greger M.D. FACLM front cover
Published by Flatiron Books in December 2019, How Not to Diet is a science-focused nutrition reference book — not a memoir, a cookbook, or a brief popular-science overview. Dr. Michael Greger, a physician, internationally recognized nutrition expert, and the founder of NutritionFacts.org, turns the full weight of his research practice toward a single question: what does the evidence actually say about healthy, permanent weight loss? The book is structured in three broad movements: an examination of the root causes and mechanisms of obesity; a detailed framework for an ideal weight-loss diet; and a final section that confronts widely debated approaches — ketogenic diets, intermittent fasting, and high-intensity interval training — alongside questions about exercise, metabolism, and sleep. The result, according to Macmillan's publisher description, is a guide designed to be "timeless" and capable of standing up to any future trend.
The Central Argument and Framework
Greger's core thesis, as laid out by the publisher, is that plant-based eating is not merely one option among many but a scientifically grounded foundation for sustainable weight management. He builds this case through a series of concrete dietary levers: calorie density, the insulin index, and the impact of specific foods on the gut microbiome. Rather than prescribing a rigid meal plan, the book identifies the criteria that make a diet effective — a structure that invites readers to reason about food choices rather than follow rules blindly. Beyond diet composition, Greger introduces twenty-one "weight-loss accelerators" — adjunct strategies drawn from fields including chronobiology — that are designed to work in concert with, not in place of, a solid dietary foundation. The book is explicit that these accelerators are supplements to a healthy diet, not shortcuts around one.
Significance and Reception
How Not to Diet debuted as an instant New York Times Best Seller, extending the cultural footprint Greger established with his previous book How Not to Die. Dean Ornish, M.D. — founder and president of the non-profit Preventive Medicine Research Institute and author of UnDo It! — offered a notable endorsement published on Macmillan's own site, calling it "one of the best books I've ever read on how to lose weight in sustainable ways that enhance health" and describing NutritionFacts.org as "one of the most credible sources of science-based nutrition." That kind of peer endorsement from a figure of Ornish's standing in evidence-based cardiology and lifestyle medicine signals the book's credibility within the medical community, not merely in popular wellness circles. Greger also donates 100 percent of his book proceeds to charity, including NutritionFacts.org — a fact that shapes the context in which the work was written.
Genuine Strengths
The book's most distinctive asset is its scope and evidence density. Where most weight-loss titles center on a single mechanism or a proprietary protocol, How Not to Diet ranges across calorie density, hormonal response (via the insulin index), microbiome science, circadian biology, metabolism, sleep research, and the specific claims of competing diet philosophies. Each topic is grounded in citations to research rather than anecdote. Readers who want to understand why a dietary principle holds — not just what to eat — will find that the book is structured around explanation rather than instruction alone. The publisher describes it as "chock full of actionable advice and groundbreaking dietary research," positioning it as a reference that rewards re-reading rather than a one-pass motivational read.
Limitations and Who May Struggle
The very comprehensiveness that makes How Not to Diet authoritative is also its most significant barrier. At 608 pages, the book is a substantial undertaking, and readers expecting a concise, step-by-step protocol may find the research-heavy format demanding. The book's framework is also built firmly on the premise that plant-based eating is central to weight-loss success — readers who are not open to that dietary orientation, or who follow eating patterns that diverge sharply from it, may find the prescriptive direction of the evidence less applicable to their preferences. Additionally, because the book engages seriously with contested diet approaches like ketogenic diets and intermittent fasting, it will directly challenge assumptions held by adherents of those methods — a feature or a friction point depending on the reader's disposition. Those looking for a quick-start guide or a minimalist framework will find the depth here more exhaustive than they need.
Sources & Further Reading
The key facts and claims in this review are grounded in the retrieved, verified sources listed below.
- Cited in this review
- 1
us.macmillan.com
- 2
- 3
nutritionfacts.org
- Further reading
- 4
Michael Greger M.D. FACLM, Wikipedia
- 5
- 6
- 7
- 8
- 9
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