At least most of them don't (unless they are rich and overweight). Working immigrants from Latin American countries are healthier because for one, many of the people who immigrate are very active physically, either through their work or because they don't drive as much as we do.
There is another reason - which is really worth looking at. Soft drinks in Mexico are sweetened with CANE, not High Fructose Corn Syrup.
Just thought you'd want to know.
p.s. we all need to watch our general sugar intake, so don't overdose on Mexican Coca-Cola -