The study will use a comprehensive behavioral intervention adapted for pregnant women to change dietary intake, eating behavior and physical activity. The central hypothesis of this study is that the intervention will reduce excess gestational weight gain and achieve clinical and metabolic benefits in obese and overweight pregnant women and their infants over the first year of life.

Inclusion Criteria:

• Age 18-45 years
• In first trimester of pregnancy
• Must be willing to not join any other weight control program while in the study
• BMI of 25-40 kg/m2
• Willingness and ability to attend support group meetings either in person or via web
• Must be able to read, speak, and understand English

Exclusion Criteria:

• Carrying multiple fetuses
• Gestational diabetes mellitus at study entry
• Type 2 diabetes mellitus or blood glucose >125 mg/dl at screening
• Self reported current substance abuse
• Current smoking
• Alchol consumption of more than 1 drink per day
• Preexisting medical conditions (includes bariatric surgery) or use of medications that would impact study involvement or outcomes testing
• Eating disorder in the past 2 years
• Depression or diagnosis of bipolar disorder
• Concurrent participation in any other research study that would impact participation in this investigation