The purpose of this study to determine if adding blueberries to obese children's diet will improve weight status and other medical testing. We would also like to determine if a larger research study involving blueberries is possible.

Ten children aged 12 to 17 years of age who have a BMI > 95th percentile for age and who are patients of the Center for Better Health and Nutrition will be recruited for this 12 week study.

Group 1 (Standard Therapy): Participants will be asked not to consume berries during the study so as not to confound the effects of eating blueberries. They will, however, be encouraged to consume other fruits consistent with nutrition guidelines for the Healthy Eating Plan (HEP: reduced glycemic load diet).

Participants will be instructed and receive educational handout materials on implementing HEP. In addition participants will be introduced to the use of behavioral tools (e.g. goal setting, daily tracking when goals are met, and incentives provided by the family) to help them stay on track with HEP. Participants will be seen by the dietitian at monthly intervals consistent with programmatic standard of care to review adherence to HEP, use of behavioral tools, and change in weight status.

Participants will be encouraged to attend group exercise classes five days per week or a minimum of four days per week. At the end of each exercise session, participants will receive a "sham smoothie" which contains no blueberries. The children will be directly observed by a study worker when consuming the smoothies to ensure compliance and measure how much of the smoothie was consumed.

Group 2 (Blueberry Enhanced): All the features of Group 1 with the exception that the participants will be given a smoothie that contain 1 1/2 cups of freeze-dried whole blueberries crushed into a powder per serving.

Inclusion Criteria:

• Children 12 to 17 years old at the time of enrollment
• Children with a BMI ≥ 95th percentile for age
• Children participating in a weight management program at the CBHN.

Exclusion Criteria:

• Children/parents/guardians who appear unable to understand the study
• Children/parents appear unable to meet the requirements of participating, specifically not missing more than 1 consecutive week during the 12 week intervention
• Children who have a medical condition or development impairment that precludes them from participating in an exercise program
• Children who have type 2 diabetes
• Children who have been diagnosed with hypertension
• Children who are taking a statin
• Children who are pregnant or have given birth within 6 months
• Children with a history of significant cardiac disease leading to cardiovascular instability
• Children who have food allergies or are lactose intolerant
• Children who are unable to finish at least half of the smoothie while they taste it after the consent/assent process or decide after tasting the smoothie that they are no longer interested in participating.