This research study intends to learn about whether early intervention can help to prevent non-alcoholic fatty liver disease (NAFLD) in adolescents. Potentially eligible adolescents who are seen at the University of Wisconsin (UW) Pediatric Fitness Clinic will be asked to join the study. Patients who agree to participate in the study will be randomized into either the intervention group or the control group. The intervention group will follow a low-fructose diet. In addition, participants will be asked to return to the clinic for 4 follow-up visits during a 6-month interval.

This will be a prospective, randomized, controlled trial for obese adolescents. Sixty obese youth (male and female), age 11-17 years with BMI >95 %tile for age and sex and one parent/guardian will be recruited for inclusion into the study at an initial pediatric fitness clinic visit. Consented subjects will be stratified by gender and ethnicity and randomized into low fructose or standard weight loss dietary intervention groups.

Inclusion Criteria:

• 11-17 years of age
• BMI >95%tile for age and sex
• Being seen for an initial clinic visit at the UW Pediatric Fitness Clinic
• Parent willing to participate in study

Exclusion Criteria:

• History of chronic disease that effects hepatic or renal function including: Type 1 or Type 2 diabetes mellitus, known liver disease or other chronic illness.