Diet & Cancer: What’s the link?

Woman holding vegetable basket

Most of us are aware that the foods we choose to eat, or not to eat may impact our health, but to what extend?

A recently published study in the Journal of the National Cancer Institute clearly reveals the link between dietary intake and cancer risk. Researchers in the USA created a model that combined data on the dietary intake of the population and the national cancer incidence rate and used it to calculate the yearly proportion of new cancer cases attributable to poor dietary intake.

The results of the study showed that in 2015 more than 80000 new cancer cases in the USA could be linked to suboptimal dietary intake. A low whole grain intake was linked with the largest number and proportion of new cancer cases, followed by low dairy intake, high processed meat intake, low vegetable and fruit intake, high red meat intake, and high consumption of sugar-sweetened beverages. Furthermore, the study also demonstrated that apart from dietary factors, being obese and not meeting the recommended amounts of physical activity also contributed to cancer risk.

The results of this study highlight the opportunity to reduce the burden of cancer by improving our diets and lifestyle. How can we do this?

To prevent cancer World Cancer Research Fund recommends the following:

  • Ensure that body weight during childhood and adolescence projects towards the lower end of the healthy adult BMI range
  • Keep your weight as low as you can within the healthy range throughout life (BMI of 18.5–24.9)
  • Avoid weight gain throughout adulthood
  • Be at least moderately physically active and follow or exceed national guidelines
  • Limit sedentary habits.
  • Consume a diet that provides at least 30g per day of fiber from food. Include foods containing wholegrains, non-starchy vegetables, fruit and pulses (legumes) such as beans and lentils in most meals.
  • Eat a diet high in all types of plant foods including at least five portions or servings (at least 400g or 15oz in total) of a variety of non-starchy vegetables and fruit every day.
  • If you eat starchy roots and tubers as staple foods, eat non-starchy vegetables, fruit and pulses (legumes) regularly too if possible.
  • Limit consumption of processed foods high in fat, starches or sugars – including ‘fast foods’; many pre-prepared dishes, snacks, bakery foods and desserts; and confectionery (candy)
  • Do not consume sugar sweetened drinks
  • If you eat red meat, limit consumption to no more than about three portions per week. Three portions are equivalent to about 350–500g (about 12–18oz) cooked weight. Consume very little, if any, processed meat.

The study results made it clear that a poor diet and a sedentary lifestyle are linked to higher incidence rates of certain cancers. However, by following the guidelines provided by the World Cancer Research Fund you can reduce your risk for certain cancers (2019).


World Cancer Research Fund (2019). Cancer Prevention Recommendations [Online]. Available at: (Accessed: 28 May 28 2019)

Zhang, F.F., Cudhea, F., Shan, Z., Michaund, D.S., Imamura, F., Eom, H., Ruan, M., Rehm, C.D., Liu, J., Du, M., Kim, D., Lizweski, L., Wilde, P., and Mozaffarian, D. (2019) ‘Preventable cancer burden associated with poor diet in the United States’, Journal of the National Cancer Institute [Online]. Available at: (Accessed: 28 May 2019)

About the author:

Tanya has been providing dietary guidance since 2009 as a registered dietician licensed in South Africa. Her goal is to help patients understand the connection between diet and diagnosis for improved nutritional well being.

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