The Claim

Higher adherence to unhealthful plant-based diets, characterized by increased intake of refined grains, sugar-sweetened beverages, sweets, and ultra-processed plant foods, is associated with a 3% higher risk of breast cancer per 10-unit increase in the unhealthful plant-based diet index (uPDI), independent of animal food intake.

Source: Healthful and unhealthful plant-based diets and site-specific cancer risk: a systematic review and meta-analysis of observational studies

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
53score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

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.

See the scientific wording

Higher adherence to unhealthful plant-based diets, characterized by increased intake of refined grains, sugar-sweetened beverages, sweets, and ultra-processed plant foods, is associated with a 3% higher risk of breast cancer per 10-unit increase in the unhealthful plant-based diet index (uPDI), indicating that poor-quality plant foods may contribute to cancer risk independently of animal food intake.

Why this might work

Eating a lot of refined grains, sugary drinks, and processed plant foods causes blood sugar and insulin to spike repeatedly. High insulin signals the body to produce more growth factors that make breast cells multiply faster. It also causes fat tissue to release more estrogen, which directly stimulates breast cells to grow. These combined effects create an environment where abnormal cells are more likely to turn into cancer.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Healthful and unhealthful plant-based diets and site-specific cancer risk: a systematic review and meta-analysis of observational studies

    People who eat a lot of sugary snacks, white bread, and soda—even if they don’t eat meat—have a slightly higher chance of getting breast cancer than those who avoid these foods. The study found this link by tracking what people ate and seeing who got cancer later.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.