Background. Pregnancy is an opportune time to initiate diabetes prevention strategies for minority and underserved women, using culturally tailored interventions delivered by community health workers. A community-partnered randomized controlled trial (RCT) with pregnant Latino women resulted in significantly improved vegetable, fiber, added sugar, and total fat consumption compared to a minimal intervention group. However, studying RCT intervention effects alone does not explain the mechanisms by which the intervention was successful or help identify which participants may have benefitted most. Purpose. To improve the development and targeting of future community health worker interventions for high-risk pregnant women, we examined baseline characteristics (moderators) and potential mechanisms (mediators) associated with these dietary changes. Method. Secondary analysis of data for 220 Latina RCT participants was conducted. A linear regression with effects for intervention group, moderator, and interaction between intervention group and moderator was used to test each hypothesized moderator of dietary changes. Sobel-Goodman mediation test was used to assess mediating effects on dietary outcomes. Results. Results varied by dietary outcome. Improvements in vegetable consumption were greatest for women who reported high spousal support at baseline. Women younger than age 30 were more likely to reduce added sugar consumption than older women. Participants who reported higher baseline perceived control were more likely to reduce fat consumption. No examined mediators were significantly associated with intervention effects. Conclusion. Future interventions with pregnant Latinas may benefit from tailoring dietary goals to consider age, level of spousal support, and perceived control to eat healthy.