Fiber-rich Foods to Treat Obesity and Prevent Colon Cancer

This study tests whether a high-fiber diet based on legumes, such as dry beans, can lead to sustained reductions in obesity and colon cancer risk in persons at highest risk, namely overweight or obese, post-polypectomy patients.

Inclusion Criteria: * free-living adults 40 to 75 years old * BMI 25-40 kg/m\^2 * able to provide documentation confirming a colonoscopy within 3 years that found ≥1 adenoma \>0.5 cm or a sessile serrated polyp (any) * English speaking * ambulatory, able to pick up food, participate in clinical exams and laboratory tests * able to provide informed consent Exclusion Criteria: * serious and/or unstable medical condition as deemed by study physician * history of colorectal cancer, bowel resection, polyposis syndrome, or inflammatory bowel disease * smoked regularly in the past year * dietary restrictions substantially limiting compliance (e.g., must be willing to be randomized to either diet) * planning on substantially changing usual exercise behavior in the next 6 months * regular or recent use of prescription medication that may alter inflammation markers or gut function as deemed by study physician * pregnant women, breast feeding women, or women planning pregnancy within the year of active study participation