As to the health exam, you may get some consultation and recommendations if your measurements show you are overweight, but it doesn't turn into some draconian process shaming you into losing the weight. I'm Japanese and never heard about such thing.
You're blessed.
High blood pressure is a medical condition, and you are telling me that a suggestion from the doctor regarding stress levels at work is bad?
And kids, cmon. Kids will make fun of anything. I did some schooling in the US and I was made fun of purely for being of a particular race.
I live in Japan and maybe my company is different, because we don't get that pressure and shame. My health check reports show a warning sign in the weight/BMI area, and that's it. Plenty of chubby and overweight people in my office too, and nobody shames them.