This study tests the feasibility and acceptability of a numberless behavioral digital scale (BDS) intervention combined with motivational interviewing (MI) to affect lifestyle changes to promote weight loss in adolescents who are obese. Half of the participants will receive this intervention, while the other half will use a digital scale along with the standard adolescent weight loss program.

The proposed pilot project seeks to enhance motivation for lifestyle change in adolescents who are obese. It will test a novel intervention that combines modified MI-based counseling and BDS. We will test the feasibility of the intervention over a 12-week period, with 24-week follow-up compared to use of standard digital scale. All participants will undergo the standard adolescent weight loss program, which includes monthly clinic visits with dietary and physical activity counseling. The MI intervention will include modified MI, brief weekly telephone reinforcement, and use of a BDS. The BDS with its mobile app offers daily feedback through colors, daily missions to promote healthy habits, and weekly healthy tips from nutritionists. In addition to the primary outcome of feasibility (daily weighing) investigators will also explore the intervention's effect on motivation, psychological outcomes and various aspects of feasibility and acceptability.

Inclusion Criteria:

• Age between 12 and 18 years
• BMI greater than or equal to 95th percentile for age and sex group or BMI greater than or equal to 35 kg/m^2
• Participant (not parent) is able to read and understand English (app is in English)
• Smartphone device with Wi-Fi and app capability
• Willingness to be randomized to any condition

Exclusion Criteria:

Age 19 years or older

• Developmental delay
• Inability to provide informed consent
• Any medical condition that, in the opinion of the PI, would place the participant at increased risk
• Use of an investigational agent in the 30 days prior to signing informed consent
• History of prior non-compliance or the presence or history of psychiatric condition (including drug or alcohol addiction) that would , in the opinion of the PI, make it difficult for the participant to comply with study procedures or follow instructions
• Females who are pregnant or lactating, by verbal report
• Pre-existing conditions (i.e paralysis, heart failure, severe autism or mental retardation, psychosis, etc.)
• Prisoners
• Lack of transportation

The investigators will provide access to all data, regardless of publication, collected on this project. All external investigators must supply a written request identifying their research questions (s) and specifying the data they would like to analyze. The request must include a data security plan and explanation of how the data would be stored and who would have access.

Data available upon request

All external investigators must supply a written request identifying their research questions (s) and specifying the data they would like to analyze. The request must include a data security plan and explanation of how the data would be stored and who would have access.