When Americans Lose Weight on Indulgent European Vacations, What Gives?

Two reasons, both obvious:

1) You tend to walk more in Europe. Anywhere in the West outside the US is much friendlier to pedestrians and walking is often the easier and more pleasant option.

2) Food in Europe is much higher quality and usually not as processed so you need far less of it to feel satiated.

The US has the worst food in the world outside of Mongolia and we seem to not even care. We resolutely follow the “cheap slop piled high” model even in the face of clearly-superior alternatives.