The obesity epidemic affects at least 300 million people worldwide, but the US leads the way, with obesity rates higher than almost all other areas of the world. The seriousness of this epidemic cannot be overemphasized: in 2000 overweight and obesity was the second leading cause of death in the US, surpassed only by tobacco use.

Previous research suggests that certain racial and ethnic groups living in the US are more likely to be obese than others, and are also more susceptible to obesity-related illnesses. But there is little information on the prevalence of obesity among US immigrants, both in general and compared to US-born individuals.

A new study in the December 15, 2004 edition of the Journal of the American Medical Association looked at the relationship between prevalence of obesity and years of US residence among immigrants and found that the longer immigrants had lived here, the more likely they were to be obese. The researchers also examined how reported diet and exercise counseling varied between immigrants and US-born adults.

About the Study

This study included data from 32,374 individuals aged 18 years and older who were all part of the 2000 National Health Interview Survey, an in-person health survey of people living throughout the US, administered by the US Bureau of the Census.

The researchers classified participants into eight different groups: US-born white, black, Latino, or Asian, and foreign-born white, black, Latino, or Asian. They further categorized foreign-born respondents based on years of residence (less than 1 year, 1-5 years, 5-10 years, 10-15 years, or greater than or equal to 15 years). They then looked at the following variables for all respondents:

  • Body mass index (BMI, a measure of weight in relation to height)
  • Dietary counseling received in the past year
  • Exercise counseling received in the past year
  • Sociodemographic characteristics (age, sex, marital status, education, place of residence, and annual household income)

The researchers measured the differences in BMI among the different groups and looked at self-reported rates of diet and exercise counseling.

The Findings

Of the people surveyed, 16% were foreign-born. These respondents were less likely to be overweight or obese than the US-born respondents (16% vs. 22%, respectively). However, the proportion of overweight and obese foreign-born respondents increased with longer duration of residence in the US: among those who had lived in the US for less than one year, 8% were obese, but among those who had lived in the US for at least 15 years, 19% were obese. This relationship between BMI and years of residence held true for all racial/ethnic groups except foreign-born blacks.

Overall, 18% of foreign-born respondents reported discussing their diet and exercise habits with a clinician in the past year, compared to 24% of US-born respondents. Foreign-born respondents were also less likely than US-born respondents to have reported that a clinician discussed their exercising habits with them in the past year (19% vs. 23%, respectively).

A limitiation of this study is that it's based on surveys administered in only English or Spanish, which means that some immigrants might not have been included. Additionally, this study examined the respondents at only one point in time; therefore it is possible, though unlikely, that the respondents who had been living in the US for 15 or more years were heavier when they moved to the US than the more recently immigrated respondents.

How Does This Affect You?

This study suggests that the longer immigrants live in the US the more likely they are to become overweight or obese. This is not surprising, given the rising obesity rates among Americans. It most likely reflects an adoption of the US lifestyle, which tends to promote sedentary behavior and excess calorie intake.

These findings also suggest that doctors are less likely to discuss diet and exercise with foreign-born patients. However, it should be highlighted that less than a quarter of all respondents in this study—whether US- or foreign-born—reported discussing their diet and exercise habits with their doctor in the past year. Given the current obesity epidemic, it’s surprising that doctors apparently discuss diet and exercise with so few of their patients.

Newly arrived immigrants often have an advantage over US-born citizens when it comes to diet and exercise. While assimilation into American culture has its advantages, one major disadvantage is adopting the high-calorie, low- motion American way of life. Despite the enormous social pressures to the contrary, immigrants would do well to continue their old eating and exercise habits. And, their new physicians could serve them better by encouraging them to do so.