PreventT2 Together: Examining the Efficacy of Couple-based Lifestyle Intervention to Prevent Type 2 Diabetes

Inclusion Criteria: 1. "Target partner" is eligible for the National DPP per CDC eligibility requirements: * BMI ≥ 25 kg/m² (≥ 23 kg/m² if Asian American), and * Do not have a diagnosis of type 1 or type 2 diabetes, and * Not currently pregnant, and * High risk for type 2 diabetes based on: (i) CDC Prediabetes Risk Test score ≥ 5, (ii) clinically diagnosed Gestational Diabetes during a previous pregnancy (for women), or (iii) a blood test result indicative of prediabetes in the past year (i.e., fasting blood glucose 100-125 mg/dl; plasma glucose 140-199 mg/dl measured 2 hours after a 75 g glucose load; or HbA1c 5.7%-6.4%). 2. The couple has lived together for 1+ years. 3. Both partners are willing to participate in the research. 4. Both partners are at least 18 years old. 5. Both partners are fluent in English. EXCLUSION CRITERIA: 1. "Supporting partner" has a diagnosis of Type 2 Diabetes. 2. Either partner: * Has a diagnosis of another chronic disease (unless no major events/changes for 3+ months), or * Is currently on medication or engaged in lifestyle intervention for prediabetes or obesity, or * Has previously participated in the National DPP, or * Reports discomfort participating in a lifestyle program with their partner, or * Reports a low level of relationship commitment (i.e., "4" or lower on a scale from 1 (do not agree at all) to 7 (agree completely) on the item "I want this relationship to stay strong no matter what rough times we encounter."; Owen et al., 2011).