Table 1.

Eligibility criteria

Inclusion criteria Age 18–35 years* BMI > 25 kg/m2 English language proficiency Currently using a mobile phone with a monthly service plan from Verizon or AT&T ** Intending to be available long enough to participate in a 24 month intervention* Willing to 1) switch to the CITY android phone for the duration of the study (24 months); 2) add the change service contract to support the CITY programming (with reimbursement from the study); and 3) agree not to disable study software while enrolled in the study Weight <440 lbs (upper limit of detection on study scales) Systolic BP at screening <160 mmHg and diastolic BP < 100 mmHg. If BP exceeds this level, participants can return for rescreening after being evaluated and treated for hypertension.*

Exclusion criteria Past or planned (within the next 24 months) weight loss surgery (e.g. gastric bypass, lap band, or liposuction); current participation in a commercial weight loss program (e.g. Weight Watcher's, Jenny Craig); current or planned enrollment in another diet/PA/weight loss intervention study.* Currently pregnant or gave birth within the last 6 months, currently lactating or breastfeeding within the last 3 months, actively planning pregnancy within the next 24 months* Cardiovascular event (heart attack, stroke, episode of heart failure, or revascularization procedure) within the last 6 month.* Current treatment for malignancy (other than non-melanoma skin cancer)* Regular use of systemic steroids, prescription weight loss drugs, and/or diabetes medications (oral or injected). “Regular use” is defined as “taking this medication most days of the week for the previous month”* Lives in same household with a CITY investigator or staff member* Household member enrolled in CITY Unable to provide informed consent Investigator discretion for safety or adherence reasons Current treatment for eating disorder or a score of 1 or higher on the ED screening questions, or a YES response to the question: “Have you recently lost more than 15 pounds in a 3-month period?”*