The Follow-up to the Multi-Million Copy Bestseller the Obesity Code

“In The Hunger Code, Dr. Jason Fung once again delivers a masterclass in breaking free from the lies of diet culture and the grip of ultra-processed foods. This is the book you’ve been waiting for.”—Ben Azadi, New York Times bestselling author of Metabolic Freedom

For generations, we've accepted the story that weight loss can never last—that as soon as we go off the diet or stop taking the medication, we revert to our old habits, regain the weight, and the calorie-counting journey starts all over again. Traditional medicine continues to treat the symptom of weight gain rather than addressing its root causes. Too often, healthcare systems intervene with quick fixes and short-term solutions, ignoring the factors that lead to sustainable weight loss that can last a lifetime.

What if the secret to long-term weight maintenance and better health isn’t just about what you eat—or even when you eat—but why you eat? 

With the food industry's reliance on ultra-processed foods and the popularity of Ozempic and Mounjaro, understanding the forces behind why we eat is more important than ever before.

In The Hunger Code, New York Times bestselling author Dr. Jason Fung reveals the three powerful forces that drive us to eat:

  • Physical Hunger

  • Emotional Hunger

  • Social Hunger

Dr. Fung also introduces the concept of the body’s “fat thermostat”—a biological “set point” that regulates how much fat your body tries to maintain. Guided by hormones and metabolism, this internal system drives hunger and energy use, explaining why lasting weight loss requires more than just willpower … 

With three Golden Rules and 50 actionable tips, The Hunger Code empowers you to recognize and respond to hunger appropriately. Learn how to slow digestion, break emotional eating cycles, and overcome social pressures to eat constantly, so you can maintain a healthy weight—from scratch, after fasting, or after using weight‑loss drugs.