As a tall but very thin man, I am convinced the clothes of a random northern European women would tend to be a better fit for me than those of a random US man,

As a tall but very thin man, I am convinced the clothes of a random northern European women would tend to be a better fit for me than those of a random US man, with something like 80%+ probability. That's partly because pants that are too wide just don't work, where can always put on pants that are too short and declare it the current italian style. So my question is: is obesity genetic in the same way that genitals and breasts are? And, if yes, why have these populations seemingly diverged with the mutational speed of fruit flies at the Hanford Site?