The World Cancer Research Fund, in its most comprehensive expert review, estimated that approximately 30 to 40 percent of common cancers are preventable through dietary and lifestyle changes. The dietary recommendations that emerge from this analysis are not based on any single food or compound but on a dietary pattern: predominantly plant foods, limiting processed meat, limiting alcohol, maintaining healthy body weight, and eating a variety of vegetables and fruits.
The Strongest Dietary Cancer Risk Factors
- Processed meat: convincing evidence for colorectal cancer; each 50g per day is associated with an 18 percent increased risk; this is the only dietary category classified as a Group 1 carcinogen by IARC
- Alcohol: convincing evidence for mouth, throat, oesophagus, liver, colorectal, and breast cancer; risk increases linearly with consumption from zero
- Obesity: excess body fat is a cause of 12 different cancer types; reducing body fat through diet is one of the most important cancer prevention strategies available
- High glycaemic index diets: associated with increased risk of colorectal, endometrial, and breast cancer in multiple prospective studies
The Strongest Dietary Cancer Protective Factors
Non-starchy vegetables reduce risk of upper gastrointestinal cancers convincingly, and probably several other cancer types. Whole grains reduce colorectal cancer risk convincingly. Physical activity reduces risk of colon, breast, and endometrial cancer. High dietary fibre convincingly reduces colorectal cancer risk. Carotenoid-rich foods probably reduce lung cancer risk. The protective dietary pattern is not a specific list of required superfoods. It is a whole food, plant-forward dietary pattern with adequate fibre, diverse vegetables, and minimal processed and ultra-processed food.