The Energy Balance Study

Inclusion Criteria: * BMI: 20-35 \*Note : For participants that come to Orientation, we are allowing participants with a variance of 0.1 either way in the BMI range: 19.9 - 35.1 * 21-35 years of age * Men and women * Email address * Access to a phone Exclusion Criteria: * Currently on medications to lose weight * \>90th percentile on the Brief Symptom Inventory (BSI) * Planning to move from the Greater Columbia area in the next 15 months * Other medical, psychiatric or behavioral factors that in the judgment of the principal investigator may interfere with study participation or the ability to follow the intervention protocol. * Changed birth control status in past 3 months * Currently taking birth control but plan to stop taking it within the next 12 months or are planning to start taking birth control in the next 12 months * Planning to have weight loss surgery * Started or stopped smoking in the past 6 months * Blood pressure ≥ 150/90 * Blood glucose ≥ 145 mg/dL @ orientation * Blood glucose ≥ 126 mg/dL @ B3 * Total cholesterol ≥ 240 mg/dl with LDL-C ≥ 190 mg/dl or Triglyceride levels ≥ 300 mg/dL * Currently diagnosed with or taking medications for a major chronic health condition * Presence of an eating disorder * Currently participating in another study