Phone app aims to help young cancer survivors shed extra pounds

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

Inclusion Criteria: * 18-39 years old at the time of consent. * Diagnosed with first invasive cancer between ages 15-39 years (self-report). * Within 10 years of diagnosis with no evidence of progressive disease or second primary cancers (self-report). * Completed active cancer directed therapy (cytotoxic chemotherapy, radiation therapy and/or definitive surgical intervention) at least six months prior to enrollment; may be receiving "maintenance" therapy to prevent recurrences (self-report). * Body mass index (BMI) of 25-50 kg/m2 Exclusion Criteria: * Type 1 diabetes or currently receiving certain medical treatments for Type 2 diabetes * Report a history of heart attack or stroke within previous 6 months * Health problems which preclude ability to walk for physical activity (e.g., lower limb amputation). Participants endorsing items 1-4 on the Physical Activity Readiness Questionnaire (PAR-Q) (experience of heart problems, frequent chest pains, or faintness or dizziness) will be excluded from the study. * Lost 5% or more of body weight (and kept it off) in the last 3 months * Lifetime history of clinical diagnosis or treatment of eating disorder (anorexia nervosa or bulimia nervosa), OR report of compensatory behaviors within the previous 3 months. If participant reports a history of compensatory behaviors, the investigators will review their information to determine eligibility. * Currently pregnant, pregnant within the past 6 months, or planning to become pregnant within the next 12 months * Untreated thyroid disease or any changes (type or dose) in thyroid medication in last 6 months * Hospitalization for depression or other psychiatric disorder within the past 12 months. * History of psychotic disorder or uncontrolled bipolar disorder * Currently participating in a weight loss, nutrition, or physical activity study or program or other study that would interfere with this study * Currently using prescription medications with known effects on appetite or weight (e.g., oral steroids, weight loss medications), with the exception of individuals on a stable dose of SSRIs for 3 months) * Previous surgical procedure for weight loss or planned weight loss surgery in the next year * Plans for major surgery (e.g., breast reconstruction) in the next 12 months * Inability to speak and read English * Does not reside in the United States * Do not have mobile phone with data plan or willing to be contacted by study through text messaging * No Internet access * Not willing to be randomized to either intervention arm