Living in America makes you fatter, and not in a good way: People who participated in the National Health Interview Survey were measured for weight and were also asked how many years they had lived in the United States. People gain weight as they age, so I calculated mean pounds for those between the ages of 31 and 35 (N=1,202), and this what I found:


Mean weight in pounds

Men
less than one year in U.S. 164.65
1 to less than 5 years 160.78
5 to less than 10 years 164.36
10 to less than 15 years 165.36
15 years or more 172.56

All American men ages 31-35 181.03

Women
less than one year in U.S. 132.71
1 to less than 5 years 131.99
5 to less than 10 years 133.67
10 to less than 15 years 137.93
15 years or more 139.68

All American women ages 31-35 143.82

It looks like people drop a little in the first few years, but after that they get fatter. But immigrants here even 15 years or more are still several pounds lighter than average. (If you're paying attention, you might be thinking that they remain lighter because they are shorter. I created a new variable by dividing weight by height. The mean score for all American men is 2.57, and 2.23 for women; for immigrants here 15 years or more, it's 2.51 for men and 2.19 for women, so you have a point).

There was a time when gaining a few pounds after reaching America's shores might have been a good thing, but I doubt it is now.