Stanford, UCLA-trained gastroenterologist highlights Harvard study list of 14 foods to avoid to reduce colon cancer risk

Gastroenterologist Dr Wendi LeBrett highlights 14 food items that one should avoid to reduce risk of colon polyps, the precursor to colon cancer.

Colon cancer, also known as colorectal cancer, is the third most common cancer globally, accounting for approximately 10 percent of all cancer cases and is the second leading cause of cancer-related deaths worldwide.

Overall, 1 in 24 men and 1 in 26 women are at risk of developing colorectal cancer in their lifetime, per American Cancer Society. Therefore, it is necessary that we safeguard ourselves from this cancer by adopting healthy lifestyle choices, including regular exercise, adequate sleep, and a balanced diet.

While knowing what to eat is important, it is equally necessary to know what to avoid. On November 17, Dr Wendi LeBrett, a gastroenterologist trained at Stanford University and UCLA, highlighted the foods one should limit in their diet.

Avoid ultra-processed foods to prevent colon cancer

Dr Wendi highlighted a 2025 research study recently published in JAMA Oncology by researchers from Harvard in the post. According to her, the study found an association between high consumption of ultra-processed foods and colon polyps (the precursor to colon cancer). “Limit these foods in your diet as much as possible,” she suggested.

Here are the foods you should be avoiding according to the Harvard study:

1. Packaged cookies

2. Candy and chocolate bars

3. Sugary cereals

4. Ice cream

5. Chips and puffed snacks

6. Instant ramen

7. Packaged white bread

8. Frozen waffles or pancakes

9. Chicken nuggets

10. Hot dogs

11. Deli meats with additives

12. Frozen ready meals

13. Soda and energy drinks

14. Protein bars and granola bars

15. Processed cheese slice

What did the study find?

The Harvard study found that younger women (aged ≤50 years) who eat the highest proportions of ultra-processed foods (UPFs) are at a 45 percent increased risk of developing bowel polyps, which can later develop into colorectal cancer.

The research was conducted by Andrew T Chan (Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA) and colleagues, published in JAMA Oncology.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.

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