A growing body of mortality research on immigrants has shown that the longer they live in the United States, the worse their rates of heart disease, high blood pressure and diabetes.
America is the disease! I jest. But, the American diet + cost of living is likely the reason that immigrant populations are in worse health after living in the U.S. The convenience of processed foods means that poorer immigrants are polluting their bodies more than people living in say Mexico buying local produce from village markets.
There isn’t an exact causal relationship, suffice to say we know a couple of things are true: healthy foods are expensive, immigrants to the U.S. (particularly from Mexico, particularly living in border towns) don’t make a lot of money. It’s safe to say that access to proper healthy habits is a problem for at-risk populations.