This dissertation examines the health of Mexican-Americans across generations in the United States and addresses some of the questions involving the Latino health paradox, that is, how poor immigrants could report better health than groups that have been in the United States for longer periods. Using data from Add Health, the research shows that obesity increases across generations. It examines obesity, health status and nutrition. Compared with the third-plus generation, the children of immigrants are somewhat more likely to be obese as children but less likely to be obese as adults. The higher the education of the parents, the lower the level of obesity. In terms of nutrition, the first generation eats the most fruits and vegetables, although their consumption is unrelated to obesity. The second generation is the most likely to eat fast food, frequent consumption of which doubles the odds of obesity by adulthood. Family closeness lowers the odds of obesity. All in all, the results show the complexity of the relationships between time in the United States (whether measured as an actual temporal interval or as family generations) and health patterns within immigrant groups.