Ideas for my birthday meal?

It's your birthday!

Personally, unless it's going to make you feel guilty and derail your progress for the rest of the week, I'd say you should just order what you like, and make sure you stop eating when you're comfortably full. As long as you don't over stuff yourself you're not going to do any serious damage.

Happy birthday!

In general, Japanese tends to be pretty healthy/lean... but Japanese steakhouses can be the exception. Are you talking about teppanyaki (where they do the knife show)? They tend to use fattier cuts of meat and lots of oil for the griddle. Not to mention they serve fried rice.

If it's a standard Japanese place, just stay away from the fried (tempura, tonkatsu, etc) and the rice and you should be pretty okay. The great thing about Japanese food is that it's pretty simple and plain. You can guesstimate your serving of fish, for example, by eye balling it and using the deck of cards standard. Also there's not a lot of additional ingredients to make calculating difficult. The Japanese love their food plain and unadulterated.

Source: I'm Japanese.