Book SummaryThe Obesity Code, by Jason Fung

1-Page Summary1-Page Book Summary of The Obesity Code

In The Obesity Code, Jason Fung argues that for decades, we’ve misunderstood obesity and, as a result, have consistently failed in our efforts to curb its spread. To solve this epidemic, he asserts that we need a new, comprehensive theory of obesity. Fung presents this theory, arguing that obesity is a hormonal problem that causes overeating and weight gain, rather than a problem of willpower or self-control. He contends that overcoming it involves improving your diet and fasting regularly.

Fung is a Canadian nephrologist (kidney specialist) and head of the Intensive Dietary Management Program in Toronto. After witnessing diabetes patients gain weight from [restricted term] treatment, he began to explore type 2 diabetes...

The Obesity Code Summary How We Misunderstood Obesity and Weight Loss

In this section, we’ll start by sketching the history of modern medicine’s understanding of obesity, before explaining the dominant theory of weight gain. We’ll then break down how that model falls short and lay the groundwork for understanding Fung’s new model of obesity.

A Brief History of Obesity

According to Fung, the physician Jean Anthelme Brillat-Savarin first identified the fattening role of carbohydrates as early as the 18th century. At the time, sweets, breads, beers, and starches such as white potatoes were typical European foods. Decades later, Englishman William Banting echoed Brillat-Savarin’s low-carb advice: After overcoming his own obesity by eliminating starches and sugars from his diet, he advised the public to do the same. This advice held consensus through the early 1900s, when calorie counting first came about.

(Shortform note: Brillat-Savarin, not a physician but a politician and lawyer with an interest in gastronomy, is best known for writing The Physiology of Taste. In the book,...

The Obesity Code Summary Obesity Is a Hormonal Problem

In this section, we’ll lay out Fung’s theory of obesity. We’ll start from the full picture and then break down one part at a time, until we’ve unfolded each aspect of the theory.

In short, Fung contends that obesity results from a hormonal dysfunction that centers on chronically high [restricted term] levels. Chronically high [restricted term] throws your body’s fat storage out of balance, disrupts your hunger hormones, and drives intractable weight gain. Here’s how.

(Shortform note: One systematic review of Fung’s central claim (as above) contends that current evidence does not strongly support it. In contrast, the reviewers say that his view is a minority view that is yet to be reconciled with the existing data on [restricted term] and weight gain.)

Fat Storage Depends on Your Set Weight

Fat storage, Fung explains, hinges on the interaction between [restricted term] and your “set weight.” Simply put, normal [restricted term] levels stimulate your body to store a fixed amount of fat, depending on how small or large you are. That default amount of fat is called your set...

The Obesity Code Summary How to Overcome Obesity

Now that we’ve described Fung’s theory of obesity, let’s look at how he recommends overcoming it. In short, beating obesity means changing what you eat as well as when you eat—mirroring the argument that diet composition and meal timing contribute to high [restricted term], thus causing obesity.

In practice, this means eating a healthy diet composed of whole foods and engaging in regular, 24- to 36-hour fasts. Whole foods help you feel full and don’t spike your [restricted term], while regular fasting lowers your [restricted term] levels long enough to reverse [restricted term] resistance. When [restricted term] resistance reverses, your set weight will drop and your body will adjust by burning off fat until you reach that weight.

The NOVA Food Quality Guidelines

In Fast. Feast. Repeat., Gin Stephens offers much the same solution as Fung, albeit in a less prescriptive way. Stephens stresses that restricting your diet makes it more difficult to stick to, and that meal timing is ultimately more important than what you eat. However, [this doesn’t mean that food quality is...

Shortform Exercise: Plan Your New Eating Patterns

After laying out his theory, Fung explains that you can beat obesity by changing what and when you eat. In this exercise, sketch how you might implement his recommendations.

First, consider your diet composition (what you eat). Recalling Fung’s explanations of the main culprits—refined carbs and added sugars—list anything in your regular diet that might contain these ingredients. For instance, you might eat grocery store white bread or pasta sauce with added sugar.