The Cancer Code by Jason Fung Summary

The Cancer Code presents a revolutionary framework for understanding cancer as an evolutionary disease driven by insulin dysregulation. Dr. Fung challenges traditional genetics-focused approaches, emphasizing the “soil” (body environment) over the “seed” (genetic mutations). He links obesity and type 2 diabetes to cancer risk and advocates lifestyle changes like intermittent fasting and low-carb diets to create a “hostile soil” for cancer.

This book is essential for cancer patients seeking alternative perspectives, healthcare professionals exploring metabolic connections to oncology, and anyone interested in preventive strategies. It’s particularly valuable for readers familiar with Dr. Fung’s previous work on diabetes and obesity.

Yes—it combines cutting-edge research with actionable advice, offering a paradigm shift from conventional cancer narratives. Its focus on modifiable risk factors like diet and insulin levels makes it a practical complement to traditional treatments.

The theory posits that cancer develops through two factors: genetic mutations (“seed”) and the body’s internal environment (“soil”). Dr. Fung argues that modern medicine overemphasizes genetic targeting while neglecting metabolic factors like insulin resistance that fuel cancer growth.

Chronic high insulin levels create a pro-growth environment, accelerating cell division and increasing DNA replication errors. This metabolic dysfunction—common in obesity and type 2 diabetes—explains why these conditions elevate cancer risk.

Key strategies include:

• Intermittent fasting to lower blood glucose and insulin
• Reducing refined carbohydrates and sugars
• Maintaining healthy weight through dietary modifications

While mainstream oncology focuses on genetic mutations and targeted therapies, Dr. Fung emphasizes systemic metabolic factors. He critiques the oversimplification of cancer as purely a genetic disease, advocating for holistic environmental interventions.

Some oncologists argue the book oversimplifies cancer’s complexity and understates the role of genetic factors. Critics note that while metabolic interventions show promise, they shouldn’t replace evidence-based treatments like chemotherapy.

The book extends his insulin-centric model from The Diabetes Code and The Obesity Code, positioning cancer as another manifestation of metabolic dysfunction. This trilogy establishes insulin resistance as a root cause of modern chronic diseases.

• “The seed of cancer may exist in all of us, but the power to change the soil is in our hands.”
• “Cancer is not an invader—it’s an evolutionary process within our own cells.”

While not rejecting conventional therapies, it advocates combining standard care with metabolic interventions. Fasting during chemotherapy, for example, may enhance treatment efficacy while reducing side effects.

Its preventive framework empowers healthy individuals to reduce cancer risk through dietary choices. The book positions cancer prevention as a modifiable lifestyle factor rather than genetic fate.