Colon cancer rates are rocketing among athletic young people in their 20s, 30s, and 40s, and survival rates are dropping. The most convenient explanations for the rise in young colon cancer are diet and weight. We know diet can influence colorectal cancer risk, and it's something people can fix, to a degree. Plus, our diets have changed. These days we all consume more sugar, more ultra-processed foods, more oil and butter, while moving less. Still, doctors say the trend we're seeing now defies neat categories of genetics or lifestyle, and it's baffling. Other factors are clearly messing with our digestive systems, but they're tough to pinpoint. Pollution, microplastics, and artificial light " all are pervasive in society, yet very tricky to study. Something shifted in the 1960s. Everyone born after 1960 has a higher colon cancer risk than previous generations. In the US, young colon cancer rates have been rising about 3% every year since the early 1990s, according to National Cancer Institute data. It's hard to dismiss the role our changing food landscape has played. We are undoubtedly eating worse than our grandparents did 100 years ago. Take fiber, for example. Found in abundance in whole plant foods like beans, it is a nutrient clearly associated with lower risk of cancer. Some of the most popular foods in US supermarkets ... have fiber stripped out during processing, and extra salt, sugar, and oils added in to make them more palatable and shelf-stable.