• The percent change in body weight from the baseline (randomization) to Week 60 (after one year of maintenance therapy).
  

• Changes from either baseline to Week 60 and/or Week 112, or enrollment to Week 60 and/or Week 112 in absolute body weight, Body Mass Index (BMI), body measurements, fasting lipid profile.
  

Topiramate is not approved for the treatment of obesity. This double-blind, placebo-controlled study assesses long-term effectiveness and safety of topiramate in patients with obesity. After completing 6 weeks of run-in phase (a single-blind placebo-treatment phase during which patients begin non-pharmacological therapy), patients will be randomized to receive either topiramate or placebo. Topiramate group will receive 16mg of topiramate and the dose will be titrated over 8 weeks. Patients will then receive two years of treatment. Effectiveness will be evaluated by body weight, Body Mass Index (BMI), anthropometric measurements (waist circumference, hip circumference, waist/hip ratio), fasting lipid profile, fasting plasma glucose, HbA1c, fasting uric acid, fasting insulin, blood pressures, body fat compositions, mass of left ventricle of the heart (as measured by echocardiography), and Health Related Quality of Life scores. Safety evaluation (incidence of adverse events, laboratory tests, electrocardiogram, vital signs) will be performed throughout the study. The study hypothesis is that topiramate will be effective in achieving and maintaining weight reduction in obese patients.

During the initial 8 weeks, the doses of topiramate or placebo will be gradually increased to the target dose (either 96mg, 192mg, or 256mg daily by mouth) and the doses will be maintained for 2 years.