Colorectal cancer is a leading cause of cancer death among people under 50 in the United States. There’s mounting evidence linking an unhealthy diet—in particular, one high in processed meat and fat, and low in fruits and vegetables—to early-onset colorectal cancer. And for younger adults, unhealthy diets are much more common than in past decades. Making lifestyle changes is important to lower your risk, but among other things, you should also know your family history and schedule your regular colonoscopy if you’re 45 or older.