Diet study aims to cut colon cancer risk in overweight adults

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria * Persons ages 19 and older * The subject has been properly informed of the study, they agree to participate, and sign the Informed Consent document(s) * Measured body mass index of 25-45 kg/m2 at the study eligibility visit months OR waist circumference \> 88 cm for women or \> 102 cm for men. * Reasonably stable weight in the last two months * Increased risk of colorectal cancer as defined by: Prior adenomatous polyp or serrated polyp OR prior resected early stage CRC (Stage I-IIIA or T1-3, N0-1, M0) OR a history of CRC in at least one primary relative or in at least two secondary relatives OR a polyp was found with a recommended follow-up colonoscopy in less than 8 years OR A known genetic condition that increases risk of CRC * Good general health * Have reasonable control over their own dietary intakes * Not expecting major lifestyle changes in the next 12 months. * Not expecting a change in hormonal therapies over the next 12 months * Have and use a smartphone with web access * Can be contacted by telephone for support calls * Read and speak English * Are able to follow a diet high in fiber-containing foods * Agree to be randomized to a control condition of usual care versus a dietary intervention involving app use and telephone contacts * Successfully complete three 24-hour dietary recalls online prior to baseline with plausible dietary intakes * If taking medications for conditions that are affected by diet (diabetes, high blood pressure) must be willing to continue to follow-up with their personal medical provider as needed to manage those conditions and the medication dosing, which may need to be adjusted due to diet changes. * Has been properly informed of the study and signed the Informed Consent document Exclusion Criteria: * Persons with BMI \>45 kg/m2 since very high BMI values could indicate more prevalent health problems. * On medically prescribed diets or other medical contraindications to dietary modification * Are within 12 months of bariatric surgery * Pregnant or lactating women or women contemplating pregnancy for the duration of the protocol * Taking anti-coagulants that interfere with ability to obtain a blood sample * Has a history of cytotoxic treatment (radiation, chemotherapy) for any type cancer within the last 12 months, except for basal cell or squamous cell tumors of the skin that have been surgically excised and required no further treatment * Have cancer at the present time * Dietary intakes with substantial nutrient deficiencies that would require extensive counseling to correct, such as obtaining a large portion of calories from alcohol * Unable to make their own daily food choices * Showing evidence of lack of reliability or non-adherence to study procedures (for example, missing an eligibility screening or baseline enrollment appointment more than twice; unable to recall the previous day's diet) * Reported dietary intakes reported that are not plausible or highly unusual as reported on the ASA24 (for example: \<500 or \>3500 kcal/day for women and \<800 or \>4200 kcal/day for men; or reporting too few foods eaten) * Has an infectious disease at the present time (such as HIV or hepatitis C). * Unable to read, write, or speak English * Unable to give informed consent