Inclusion Criteria:  18-60 years old, BMI 25-40 kg/m2 insufficiently active (<60 minutes of moderate intensity activity per week). High/low internalized weight bias Access to personal smartphone device and willing to download free smartphone app for data collection  Exclusion Criteria:  Comorbid issues that might interfere with ability to engage in physical activity Factors that would influence ability to complete study protocol (e.g., cognitive, psychological) medication that would affect heart rate (e.g., beta blocker), women who are nursing or pregnant