Glaser Obesity Study

Inclusion Criteria:

* Subjects must be between the ages of 13.00 and 17.99 at week 0 (Baseline).
* Subjects must have a BMI ≥ 95th percentile for age and gender using the CDC data (see Appendix), but must weigh less than 300 pounds (\<136 kilograms) when measured during the initial physical exam at week 0 (Baseline). BMI will be calculated as follows; weight in kilograms  \[height in meters\]2. This cutoff has been established due to the weight-bearing limits of the table used in performing the DXA scan. Once enrolled, if a subject's weight progresses above 300 pounds, s/he may continue in the study whether it is possible to perform DXA or not.
* Completion of informed consent/assent process

Exclusion Criteria:

* Known diabetes as defined by the American Diabetes Association criteria
* Prior drug therapy to treat diabetes or insulin insensitivity, including any form of insulin or insulin analogs; or any oral antidiabetic medication; acarbose, acetohexamide, chlorpropamide, glimepiride, glipizide, glyburide, metformin, pioglitazone, repaglinide, rosiglitazone, tolazamide, tolbutamide or troglitazone.
* Prior use of drugs to aid in weight loss, including but not limited to: Benzphetamine Hcl, Diethylpropion Hcl, Fenfluramine Hcl, Phendimetrazine Tartrate, Phentermine Hcl, Orlistat, Sibutramine Hcl Monohydrate, Didrex, Tenuate, Pondimin, Bontril-SR, Adipex-P, Fastin, Ionamin, Phentrol, Xenical, Meridia.
* Subject is currently taking the following medications at the time of the Screening visit: Cimetidine, amiloride, digoxin, furosemide, morphine, nifedipine, procainamide, ranitidine, triamterene, trimethoprim, vancomycin and quinidine, as these medications may increase metformin levels.
* Subjects will be excluded from the study if they have taken prescription-strength glucocorticoids (by any route) within three months of the screening visit. Topical glucocorticoids are acceptable if their strength is no greater than the equivalent of 1% hydrocortisone cream.
* History of any syndrome or medical disorder associated with significant obesity, including but not limited to: Prader Willi Syndrome, Bardet-Biedl Syndrome, Cohen Syndrome, Cushing syndrome or disease.
* Prior surgical therapy for obesity
* Subject to be excluded if s/he has attended a formal weight loss program within 6 months prior to the Screening visit.
* In the 6 months prior to Screening, subject has consumed alcohol more frequently than twice per week and/or subject has had more than three alcohol-containing beverages in a 24 hour period.
* Elevated creatinine (\> 1.2 mg/dl)
* Untreated disorders of thyroid function
* Elevated liver enzymes (Alanine Aminotransferase \[ALT\] or Aspartate Aminotransferase \[AST\]) \> 80 (approximately 2 times upper limit of normal)
* Mobility impairment that prevents full participation in recommended physical activity
* Other serious medical condition that the Principal Investigator or Lead Site Investigator determines may put the patient at undue risk if enrolled in the study
* Unable to comply with the protocol in the opinion of the Principal Investigator or the Lead Site Investigator
* Subjects with child-bearing potential who are unwilling to remain abstinent or use an effective method of birth control
* Previous pregnancy