Patient description: A 16-year-old girl came to the clinic complaining of weight gain and abnormal menstrual cycles. Her BMI was 24, but she has gained 5 kg in the past few weeks. She gets tired more frequently and does not have energy to go dancing with her friends. Her lab results were remarkable for high TSH levels (15 mU/L) and low free T4 levels (0.18 ng/dl). Her anti-TPO levels were extremely high (136 IU/ml). She was diagnosed with Hashimoto disease. She does not smoke and she is not sexually active.

Clinical trial eligibility criteria: eligible ages (years): 0.0-999.0,  Obesity Diet Therapy Diabetes Type 2 Adult pregnant women of any race or ethnicity may participate if they meet each of the following 1. At least 18 years of age. 2. Receive prenatal care at the nurse midwifery/obstetrics service of PIMC and plan to continue receiving such care throughout the pregnancy. 3. Able to have an OGTT prior to 16 weeks gestation. Hyperemesis can preclude some pregnant women from successfully completing the OGTT; these women will not be excluded if the fasting blood samples can be obtained. 4. Able to have an ultrasound examination to estimate fetal age. 5. Complete initial run-in screening visits to determine whether the woman can manage the tasks required of participation in an intensive intervention if randomized to the intervention group. 6. Able to commit the time required for the interventions and follow-up. 7. Singleton viable pregnancy. A twin pregnancy reduced to singleton before 14(0) weeks by project gestational age is acceptable. An ultrasound must be conducted before randomization that shows a fetal heartbeat; there should be no evidence of more than one fetus on the most recent pre-randomization ultrasound. 8. Gestational age at randomization no earlier than 9 weeks 0 days and no later than 15(6) weeks based on an algorithm that compares the LMP date and data from the earliest ultrasound. 9. Body mass index greater than or equal to 25 kilogram / square meter based on first trimester measured weight and on measured height. The earliest weight measurement before randomization, measured specifically for the study, will be used. Reported pre-pregnancy weight will not be used to determine because of the potential for inaccuracy. If the earliest weight measurement is conducted at 14(0) to 14(6) weeks or 15(0) to 15(6) weeks, 1 pound or 2 pounds will be subtracted from the measured weight, respectively, to adjust to a first trimester weight. This weight and the resultant BMI are defined as the baseline weight and BMI, respectively  Diagnosis of diabetes prior to pregnancy or any of the following results of the oral glucose tolerance test at visit #1 that suggest diabetes prior to pregnancy: HbA1c greater than or equal 6.5 %, FPG greater than or equal 126 milligrams per deciliter, or 2-hour post-load plasma glucose greater than or equal 200 milligrams per deciliter (75 grams oral glucose tolerance test). All potential participants will have HbA1c and a 75 grams oral glucose tolerance test performed prior to randomization Women who meet the above for diagnosed or presumed diabetes prior to pregnancy will be excluded. Others who meet for GDM will be eligible. for GDM diagnosis will be based on ADA 2012 (at least one of FPG greater than or equal to 92 milligrams per deciliter, 1 hour PG greater than or equal 180 milligrams per deciliter, or 2 hour PG greater than or equal to 153 milligrams per deciliter.) Known fetal anomaly Planned termination of pregnancy History of three or more consecutive first trimester miscarriages Past history of anorexia or bulimia by medical history or patient report. Binge eating disorder (BED) is not an exclusion Current eating disorder diagnosed by EDE-Q questions 2-4 and confirmed after discussion with the participant by study staff Actively suicidal defined as a value greater than or equal 2 on the BDI-II question 9 Prior or planned (within 1 year of expected delivery) bariatric surgery Current use of one or more of the following medications