Book excerpt: The rates of obesity have soared in the past couple decades in the United States. Yet obesity has not affected all groups equally. A disparity in the prevalence of obesity among different ethnic and racial groups continues to exist. More Latino children and adults are affected by obesity than their white counterparts. This is a pressing issue in California, where the Latino population is predicted to become a majority during the next few decades. There is a need for research that investigates how to address obesity in Latino populations, especially those of Mexican descent. This dissertation presents findings from the Niños Sanos, Familia Sana (NSFS, Healthy Children, Healthy Family) study conducted between June 2010 and May 2015. The study sample included Mexican-origin children ages 3 to 8 years (n=594) and their parents living in the rural Central Valley of California. This dissertation was completed in three phases. The first phase consisted of qualitative research among parents to explore their perspectives on childhood obesity, barriers to a healthy lifestyle, and ideas for obesity interventions. Five focus groups were conducted among Mexican-origin parents (n=33) in 2010-2011 in Firebaugh CA. A major theme that emerged from these focus groups is that the transition to school negatively influences children's eating preferences. A nutrition message that resonated with participants was eating meals as a family and the role it can play in living a healthy lifestyle. The second phase compared different methods for the assessment of fruit and vegetable consumption within the NSFS study. To understand how dietary patterns and food behaviors change over time, instruments such as food frequency questionnaires (FFQ) and dietary recalls are commonly used. However, there are newer methods and technology that allow for more objective measurements of diet. Fruit and vegetable intake among Mexican-origin children (n= 51) was assessed using a noninvasive technology that measures the levels of carotenoids in the skin. The results from this chapter demonstrate a significant correlation between skin carotenoid levels and reported dietary recall vegetable intake (r=0.41, p=0.003), but not with dietary recall fruit, FFQ fruit, and FFQ vegetable consumption. Lastly, the third phase examined differences between intervention (n=105) and control (n=70) children in consumption of vegetables and fast/convenience food from baseline until the end of the second year of the intervention. The predictors of fruit and vegetable consumption were also examined in this study. At the end of year 2, no significant effect of the intervention was observed between groups in vegetable consumption (p=0.579). However a significant reduction on fast and convenience food consumption (p=0.001) was observed in the intervention children only. After adjusting for covariates, child BMI z-score was found to have a negative relationship with vegetable intake (n=108, [beta]=-2747.5, SE=849.4, p=0.002). The findings from this dissertation contribute to the obesity literature and provide the foundation for future nutrition and obesity interventions, which are culturally adapted to Mexican-origin populations.