Research Studies

Female or Male Age 18-65 years Body Mass Index 27-46 kg/m2 Sedentary: defined as <150 minutes per week of voluntary exercise at moderate intensity or greater and < 60 min per day of total habitual physical activity (i.e. work related, transportation related) at moderate intensity or greater, over the past 3 months. No self-report of acute or chronic disease No plans to relocate within the next 12 months No plans for extended travel (> 2 weeks) within the next 12 months No nicotine use For Females: -Not currently pregnant or lactating -Not pregnant within the past 6 months -Not planning to become pregnant in the next 12 months

Inclusion Criteria: Female or Male; Age 18-65 years; BMI 27-46 kg/m2; Sedentary: <150 minutes per week of voluntary exercise at moderate intensity or greater and < 60 min per day of total habitual physical activity at moderate intensity or greater, over the past 3 months; No self-report of acute or chronic disease; No plans to relocate within the next 12 months; No plans for extended travel (> 2 weeks) within the next 12 months; No nicotine use; Live or work within 30 minutes of the AHWC; Capable and willing to give informed consent, understand exclusion criteria, and accept the randomized group assignment; Have a PCP (or are willing to establish care with a primary care physician prior to study enrollment); For Females: Not pregnant or lactating, not pregnant within the past 6 months, not planning to become pregnant in the next 12 months. Exclusion Criteria Diastolic blood pressure > 100 mm HG or systolic blood pressure > 160 mm HG; Resting heart rate >100; Diabetes; Undiagnosed hypo- or hyper-thyroidism or history of uncontrolled thyroid disorder; Hematocrit, white blood cell count or platelets significantly outside the normal reference range; Triglycerides > 400 mg/d; LDL cholesterol > 190 mg/dL; Abnormal resting electrocardiogram; Presence or history of any metabolic or chronic health problems which would affect appetite, food intake, energy metabolism, or ability to optimally participate in the exercise component including: CVD, peripheral vascular disease, cerebrovascular disease, significant cardiac arrhythmias or cardiac valve disease, diabetes, uncontrolled hyper- or hypothyroidism, uncontrolled hypertension, cancer (within the last 5 years, except skin cancer or other cancers considered cured with excellent prognosis), HIV infection, significant GI disorders, significant pulmonary disorders, significant renal, musculoskeletal, neurologic, hematologic, or psychiatric disease; Significant GI disorders; Significant pulmonary disorders including: COPD, interstitial lung disease, cystic fibrosis, or uncontrolled asthma; Symptoms suggestive of CVD: chest pain, shortness of breath at rest or with mild exertion, syncope; Regular use of prescription or over-the-counter medications known to significantly impact appetite, weight, or energy metabolism; Regular use of systemic steroids (other than Oral Contraceptive Pills); Regular use of obesity pharmacotherapeutic agents within the last 6 months; Previous obesity treatment with surgery or weight loss device, except: (1) liposuction and/or abdominoplasty if performed > 1 year before screening, (2) lap banding if the band has been removed > 1 year before screening, (3) intragastric balloon if the balloon has been removed > 1 year before screening (4) duodenal-jejunal bypass sleeve, if the sleeve has been removed > 1 year before screening or 5) AspireAssist or other endoscopically placed weight loss device if the device has been removed > 1 year before screening; Current alcohol or substance abuse; Nicotine use (past 6 months); History of clinically diagnosed eating disorders including anorexia nervosa, bulimia, binge eating disorder; Current severe depression or history of severe depression within the previous year, based on DSM-IV-TR criteria for Major Depressive Episode; History of other significant psychiatric illness which in the opinion of the Study MD would interfere with ability to adhere to dietary or exercise interventions; Currently participating in or planning to participate in any formal weight loss or physical activity programs or clinical trials; Participation in a weight loss program using the Colorado Weigh curriculum within the past 3 years; Currently following an IMF weight loss diet plan; Weight loss >5kg in past 3 months for any reason except post-partum weight loss, weight gain >5kg in past 3 months