The Obesity Code
Unlocking the Secrets of Weight Loss


Jason Fund MD blogs at Intensive Dietary Management.
The Obesity Code – A Book Review
Want to break the ‘code’ to reaching your ideal weight? Don’t worry; it’s already been cracked for you! The Obesity Code, Unlocking the Secrets of Weight Loss, by Jason Fung MD, is the key to a healthier lifestyle.
Author Jason Fung MD is a Toronto nephrologist treating patients with end-stage kidney disease. After years of treating his patients’ symptoms, Fung decided to investigate the root causes of Type 2 Diabetes, the most common cause of kidney disease.
His conclusion is that a ketogenic (low-carb, moderate-protein, high-fat diet) and intermittent fasting are excellent methods of reducing high insulin levels that cause obesity.
Fung’s quest began as he realized that he and his physician colleagues in the modern medical community, as well as the pharmaceutical industry, were focused on only treating the symptoms of diseases caused by obesity, not its core causes.
In The Obesity Code Fung relates and examines the evidence-based medical science connecting obesity and type-2 diabetes, and how the science should inform us on what and how often we should be eating.
As a preface, Fung concisely poses the question: What actually causes weight gain and what can we do about it? His thesis presents “a fresh framework for the understanding and treatment of obesity represents a new hope for a healthier future.”
After describing society’s well-documented ‘epidemic’ of obesity, Fung artfully and scientifically points out that our current understanding of the cause of obesity as ‘calories in, calories out’ is fundamental flawed. Fung describes the studies proving this longstanding ‘eat less, move more’ theory to be completely wrong and useless. Diets based on this theory always fail.
Instead, Fung reveals that real real science points to a “hormonal theory” of obesity, that is to say that obesity is and should be treated as “a hormonal dysregulation of fat mass.” Fung puts it this way, “Obesity is not caused by an excess of calories, but instead by a body set weight that is too high because of a hormonal imbalance in the body.”
With concise, succinct and easily understandable scientific analysis, Fung explains that although obesity is a multi-faceted syndrome, high blood insulin levels and the resulting insulin resistance are THE CAUSE of obesity.
Insulin is a key hormone vital to the body’s use of nutrients. Over time, persons who have maintained persistently high insulin levels will develop a resistance to normal levels of insulin and need more and more insulin just to allow the energy into their body’s cells. Fung puts it this way, “Persistent high insulin levels lead gradually and eventually to insulin resistance. Insulin resistance in turn leads to higher insulin levels. But the crucial starting point for of the vicious cycle is high insulin levels.”
The real problem is that the current treatment of insulin resistance (diabetes) is simply to give more insulin, similar to treating a cocaine adict with more cocaine or an alcoholic with more alchol. Diabetics treated with insulin will invariably gain more and more weight due to the increased infusion of insulin. Fung is totally dissatisfied with this approach and believes that the proper cure is through changing what and how often we eat. That is, eating less carbs and protein, which stimulate insulin production, and eating more fats which do not.
And, the cure also involves eating less frequently and actually fasting for at least 24 hours several time a week.
What does this suggest for a perfect diet? Fung informs us that what we eat (meal composition of carb, protein and fat) is important, but meal TIMING is equally important. What we eat, such as the glycemic index of the food we eat (candy vs. lettuce) determines how high blood insulin spikes. But just as important is the length of time insulin levels stay high. If insulin levels are chronically and persistently high because we are always eating and ingesting insulin stimulating foods, then insulin resistance is sure to develop.
Fung’s review of the evidence leads to the conclusion that reducing the number of meals/snacks eaten is twice as important of a factor in preventing obesity as a change in diet (meal content). So, if timing is that important, when and how often are meals to be eaten?
Before speaking to meal timing, specifically the idea of fasting, Fung debunks the longstanding, but disproven, myths regarding meal timing. For example, the idea that we should eat frequent small meals or ‘grazing’ to prevent low blood sugar is not supported by studies of subjects fasting for days or weeks or longer who do not develop low blood sugar problems.
What not to eat? Fung addresses the standard American diet and what is wrong with it. Refined sugar, artificial sweeteners, processed grains and carbs, as well as too much protein, all raise insulin levels quickly and substantially.
What should we eat to avoid overstimulation of insulin and provide the correct balance of macronutrients? It turns out that the Dr. Atkins was on the right track with his low-carb approach, but not with the high protein aspect of his diet plan. So, Atkins had a partial solution, but the idea that carbs were the sole driver of insulin elevation was incomplete.
Research cited by Fung confirms that dietary protein also causes a rise in insulin levels, with dairy products also being a potent stimulate of insulin. In fact, all food stimulates insulin production, but fats have the weakest stimulating effect, and pure natural fats, such as olive oil, do not stimulate insulin production at all.
As a side note, the ‘fat phobia’ of the last half century was a fraud, pure and simple. Fung discusses it, but you’ve heard the story by now. No need to repeat it here.
So, what do we eat and how often? This is the question. Here a Fung’s steps:
1. Reduce consumption of added sugar in any form and there are many. Read labels; sugar in its many forms is ubiquitous.
2. Reduce consumption of refined grains.
3. Moderate protein consumption to 20-30% total calories.
4. Increase consumption of natural fats, such as coconut oil, leaf lard, butter, olive oil and beef tallow.
5. Increase healthy fiber and try to use more vinegars.
But the most revealing research centers on the issue of “when to eat?” Fung argues that we should be breaking up the periods of high blood insulin levels caused by frequent eating through periodic FASTING, preferably for 24-36 hours. Besides the other healthy effects of fasting, insulin levels will be lower for longer, not elevated most of the time. Fung presents credible evidence that fasting alone will break the cycle leading to insulin resistance.
Be assured that none of the myths suggesting the dangers of fasting are true. Fasting for 24-36 hours or longer yields great outcomes. (Of course, if a person has existing health issues or for long fasts, only fast under the close medical direction of your physician.)
One added bonus: When you’re fasting you don’t need to worry about what to eat!
For more on fasting, read Fung’s book titled The Complete Guide to Fasting.
In sum, The Obesity Code is a must-read because it is the most up to date writing on diet to date. It’s truly the key to breaking out of the prison of obesity.
Read More on this subject by Jason Fung in his blog post titled The Calorie Debacle.
This is a fantastic, concise review of the book… except for the typos. Most of the review references Dr Fung as “Jung”! I’d love to share this article with my friends, but it’s distracting that the author’s name is continually mis-spelt.
Thank you for reading this review. I hope the typos are now corrected so that you can share this important info. Thanks again … Johnnie