Obesity among the Mexican-origin adult population in the U.S. has been associated with longer stays in the U.S. and with being U.S.- vs. Mexican-born, two proxies for acculturation. This pattern is less clear for Mexican-origin children and young adults: recent evidence suggests that it may be reversed, with foreign-born Mexican youth in the U.S. at higher risk of obesity than their U.S.-born Mexican-American counterparts. The objective of this study is to evaluate the hypothesis that the immigrant advantage in obesity prevalence for Mexican-origin populations in the U.S. does not hold for children and young adults. 

Researchers used data from the Los Angeles Family and Neighborhood Survey (N = 1143) and the California Health Interview Survey (N = 25,487) for respondents ages 4–24 to calculate the odds of overweight/obesity by ethnicity and nativity. 

Findings: Researchers found that young Mexican immigrants and second-generation Mexican-American men (ages 18–24) were more obese than the third and subsequent generations; the same was true for young first and second-generation Mexican-American women (ages 12–17). What has happened to the so-called immigrant advantage? As recently as 10 to 15 years ago, many studies suggested that Mexicans ate healthier foods than their northern neighbors. But studies are now revealing that Mexicans are adopting more of an American diet -- they are consuming more fats and processed foods. 

Researchers warn that rising obesity rates among Mexican-Americans should be a concern on both sides of the border, particularly since there will be more Latino than non-Hispanic white school children in the United States by 2050.