The Study
Healthful and unhealthful plant-based diets and site-specific cancer risk: a systematic review and meta-analysis of observational studies
This study looked at lots of people over many years and found that those who ate more healthy plants like fruits, veggies, and whole grains tended to get less cancer—but that doesn’t mean eating those foods caused the lower cancer risk. Other things, like exercise or not smoking, might also be helping.
Analysis score
Maximum 85 for a systematic review with meta-analysis.
Where the score came from
Eating lots of fruits, veggies, whole grains, and nuts may help lower cancer risk, but eating lots of sugary snacks and white bread—even if they’re plant-based—might make it worse.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 553 / 100
Quality score
Systematic reviews and meta-analyses of cohort studies. They sit above a single cohort study but below a single randomized trial, because the underlying evidence is still observational.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes—these changes are meaningful at a population level, equivalent to reducing cancer risk by eating more whole foods and avoiding processed snacks.
- 2Healthful plant foods: 6% less breast cancer, 5% less colorectal cancer, 23% less liver cancer per 10-point diet score increase.
- 3Unhealthful plant foods: 3% more breast cancer per 10-point score increase.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
European Journal of Nutrition
Year
2026
Authors
Mercedes Gil-Lespinard, Lucía Iglesias-Vázquez, Paula Jakszyn
Related Content
Claims (7)
People who eat more high-quality plant foods, such as fruits, vegetables, whole grains, nuts, and legumes, have a 5% lower risk of colorectal cancer for every 10-point increase in a healthful plant-based diet score. Similar results are seen with broader plant-based diet measures.
People who eat more whole grains, fruits, vegetables, legumes, and nuts have a 6% lower risk of breast cancer for every 10-point increase in a diet quality score based on these foods.
People who eat more unhealthy plant-based foods, such as refined grains and sugary drinks, do not show a statistically significant increase in colorectal cancer risk, although there is a slight upward trend, and this effect is weaker than what is observed for breast cancer.
People who eat more refined grains, sugary drinks, sweets, and ultra-processed plant foods have a 3% higher risk of breast cancer for every 10-point increase in a diet score measuring these foods, regardless of how much animal food they consume.
People who follow healthful plant-based diets have a 23% lower risk of liver cancer for every 10-point increase in their diet quality score, and those who follow plant-based diets overall have a 17% lower risk of liver cancer. These patterns are linked to lower levels of insulin resistance and inflammation.
People who follow plant-based diets more closely have a 24% lower risk of developing lung cancer compared to those with the lowest adherence, regardless of smoking history.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.