Dr. Jason Fung
Four weeks. One book. A complete case for why calorie counting keeps failing — and how insulin, food quality, timing, and age actually govern body weight.
The Obesity Code is nephrologist Dr. Jason Fung's case against the "calories in, calories out" model of weight gain. Drawing on decades of clinical experience treating diabetes and obesity, Fung argues that body weight is regulated hormonally — not arithmetically.
His central claim is that insulin is the primary driver of fat storage, and that chronically elevated insulin — from refined carbohydrates, frequent eating, and sugar — keeps the body locked in storage mode regardless of total calories consumed.
The book walks through why decades of "eat less, move more" advice have coincided with rising obesity, what actually spikes insulin, how meal timing and fasting windows offer a simpler lever than food choice alone, and how the body's metabolic rules shift with age.
Over four weeks this September, the West Egg Health Newsletter worked through that case one layer at a time — from debunking the calorie model, to the role of insulin and sugar, to timing and eating patterns, to what a metabolic reset looks like after 50.
Obesity is hormonal, not mathematical — insulin, not calorie math, decides whether energy is stored or burned.
Not all calories are equal — sugar and refined carbs spike insulin far more than whole foods at the same calorie count.
Severe restriction backfires — cutting calories too hard can collapse resting metabolism instead of fixing the setpoint.
Timing is a lever too — meal frequency and fasting windows shape insulin as much as food choice.
Metabolism shifts after 50 — hormonal changes with age mean the same habits need to be applied differently.
The environment drives the epidemic — genes set susceptibility, but modern eating patterns pull the trigger.
Each issue stands alone as a complete lesson. Together they form a comprehensive guide to understanding — and resetting — your metabolism.
Week 1 · September 1–7For fifty years the official advice has been "eat less, move more" while obesity rates climbed. This issue makes the case that the calorie model itself is missing the hormonal system that actually decides where energy goes.
Week 2 · September 8–14With insulin established as the key hormone, this issue goes to the source: what sugar and refined carbohydrates actually do to insulin — and why not all carbs behave the same way.
Week 3 · September 15–21Beyond what we eat, this issue turns to when we eat — showing how meal timing and fasting windows are just as powerful a lever on insulin as food choice, and often simpler to apply.
Week 4 · September 22–28Three weeks of the why. This final issue applies calories, insulin, and timing to the body’s biggest metabolic shift — what changes after 50, and how Fung’s framework adapts to it.
The science in this series is actionable today. Pick up a copy of The Obesity Code, start with Week 1, and begin rethinking how your body actually regulates weight.
