I honestly don't know much about typical Japanese eating habits, but could this be more about what they're eating instead of those carbs?
Like, if it's anything like the US I wouldn't be surprised to see numbers like this simply because the non-carb food is probably mostly meat in the case of men and mostly veggies in the case of women. I don't really have numbers on percent of meat versus veggies in a diet on average by gender, but there certainly seems to at least be some culturally imposed presumptions of men gruffly devouring steaks and women laughing at salad.
If most of your diet is meat and you cut back on carbs only to eat yet more meat, you're probably not going to be as healthy as someone who eats a ton of veggies. Likewise, replacing vegetables with carbs probably sucks for your health.