The 5 best foods to fight cancer and lower your risk of death | Dr William Li

You have around 10,000 cancer cells in your body right now, but most never become dangerous. The science suggests cancer risk is not just about genetics, but how your body responds to these cells. So what can you do, day to day, to support your body’s natural defences?

In this episode, Dr William Li, a world-renowned physician, scientist, speaker, and two-time NYT Bestselling author, explains how everyday foods can fuel cancer growth or help your body keep it under control. We explore how cancer starts, why it is part of normal biology, and explain why lifestyle and environment are more important than genetics when managing your cancer risk.

Dr Li shares simple guidance on eating patterns that support your body’s defences, including increasing plant-rich foods and reducing ultra-processed foods. He also highlights everyday habits such as staying active, supporting gut health, and limiting toxin exposure as ways to tip the balance in your favour.

If your body is already managing cancer cells every day, what small changes could help it do that job better?

🌱 Try our science-backed and tasty wholefood supplement Daily30

Get our brand-new app and Gut Health Test designed by world-leading gut health and nutrition scientists to build healthy eating habits 👉 Join ZOE

Follow ZOE on Instagram.

Timecodes

00:00 Intro

02:26 Almost everyone has microscopic tumours

08:15 We all have cancer right now?

10:45 Why most cancer cells stay harmless

13:40 The hidden trigger that fuels cancer growth

14:35 What makes cancer turn deadly

16:35 Cancer cells behave like seeds

19:05 How sunburn can lead to cancer

20:55 What smoking really does inside your body

22:20 The new way to fight cancer

24:20 Why genes matter less than you think

26:00 Is vaping worse than smoking?

27:05 The drinking habit that raises cancer risk

29:25 The environmental risk we can’t ignore

33:47 The diet pattern linked to cancer risk

35:10 Why processed meat is a class 1 carcinogen

37:25 How processed meat affects your gut

41:50 A simple way to reduce BBQ toxins

43:40 Does sugar really feed cancer?

45:51 The truth about soy and cancer

47:25 The soy study that shocked scientists

49:05 How tomatoes may lower cancer risk

51:00 Why berries are more powerful than you think

54:40 How tea and coffee support your defences

56:05 The gut link to cancer risk

57:40 Dr Li’s simplest rules to reduce risk

📚Books by our ZOE Scientists

The Food For Life Cookbook

Every Body Should Know This by Dr Federica Amati

Food For Life by Prof. Tim Spector

Ferment by Prof. Tim Spector

Good Mood Food (preorder) by Prof. Tim Spector

Free resources from ZOE

The Hormone Harmony Guide: Tuning Your Body’s Internal Orchestra

Eating for Better Brain Health: Your brain-gut blueprint

How to eat in 2026 - Discover ZOE’s 8 nutrition principles for long-term health

Live Healthier: Top 10 Tips From ZOE Science & Nutrition

Gut Guide - For a Healthier Microbiome in Weeks

Better Breakfast Guide

Mentioned in today's episode

Eat to Beat Disease: The Body’s Five Defence Systems and the Foods that Could Save Your Life by Dr William Li

Eat to Beat Your Diet by Dr William Li

Huge microbiome breakthrough from ZOE, thanks to community science

Shanghai Breast Cancer Study, JAMA (2009)

The Anti-Cancer Activity of Lycopene, Nutrients (2022)

Health Professionals Follow-Up Study

Have feedback or a topic you'd like us to cover? Let us know here.

Episode transcripts are available here.