Colorectal cancer deaths linked to low-fiber diets are highest in middle-income countries and lower in both poorer and wealthier countries, suggesting that economic development and dietary changes interact in complex ways with cancer risk.

Although the rate of colorectal cancer deaths per person has decreased since 1990, the total number of deaths from this cancer linked to low-fiber diets has risen because the global population has grown and aged.

In countries where people have shifted from traditional diets to more processed, low-fiber foods, deaths from colorectal cancer have increased sharply—by more than 480% in some places—suggesting that this dietary shift is strongly linked to higher cancer mortality.

Diets low in fiber, defined as less than 25 grams per day, are linked to approximately 13,145 deaths and 305,676 years of lost healthy life from colorectal cancer globally in 2021, with the greatest impact seen in people over 50 and in low- and middle-income countries.

In Southeast Asia and the Caribbean, more people die from colorectal cancer linked to low-fiber diets compared to other regions, with Cambodia having the highest rate at 1.12 deaths per 100,000 people, reflecting differences in dietary habits across regions.

The way people report how much fiber they eat affects whether studies find a link between fiber and colorectal cancer. When people use food diaries, a protective link is seen; when they use questionnaires, no significant link is found.