Part of the reason for that is the much higher death rate in infants in the US, but it is still a very hard thing to explain away. I will also say as somebody who has lived in the US, US food is high calorie, but it is not better on any dimension, than what I can buy in any European street market. Possibly foreign born Americans stick with their original diets more.. who knows. But ops point about trading quality of life for meaningless economic statistics is spot on.