The incidence of type 2 diabetes (T2D) in children is increasing, paralleling the rising incidence of obesity. Preventing children and adolescents from developing T2D is critical. The health benefits of lifestyle modifications are well documented in this population, but success rates are low. Obesity in children and adolescents increases the risk of not only T2D but other complications as well, such as hypertension, dyslipidemias and more. The investigators hypothesize that having real-time glucose data with the use of a continuous glucose monitor (CGM) in obese patients with impaired glucose tolerance will improve adherence to lifestyle modifications. As a result, a decrease in body mass index (BMI) is expected with subsequent improvement in insulin sensitivity, thus reducing risk of obesity-related complications later in childhood/adolescence and adulthood.

The purpose of this research is to evaluate if having blood sugar information from a continuous glucose monitor (CGM) during activities of daily living provides additional benefit to lifestyle modifications in reducing the risk of developing diabetes and achieving a healthier weight. A CGM is a small device often worn on the back of the arm that uses a very small needle to insert a small sensor just under the skin in the fatty tissue. The CGM device transmits the blood sugar level to either a smartphone or a special receiver.

The investigators expect patients will have an overall improvement in health by decreasing weight and therefore improving the way the child's insulin works in their body. This could result in decreased risk of obesity-related complications such as diabetes mellitus, cardiovascular disease, kidney disease, and loss of vision and/or limbs, among others.

Inclusion Criteria:

1. Children 10 to <18 years old (i.e., before their 18th birthday)
2. Impaired glucose tolerance based on standardized oral glucose tolerance test (OGTT) or fasting glucose per American Diabetes Association criteria,
3. Overweight or obese (BMI ≥85th percentile for age/sex)
4. Patients are pubertal, defined as females with breast Tanner stage II or above, or males with testicular volume ≥4 mL

Exclusion Criteria:

1. Existing diagnosis of type 1 or type 2 diabetes
2. Prepubertal
3. Taking medications that affect insulin sensitivity (e.g.,chronic corticosteroids whether systemic or inhaled). Metformin allowed if stable dose.
4. Patients and/or families not willing to wear the CGM for the duration of the study period or lack of compliance after recruitment