If you have a place with free legal services in your area you can ask them if there is such a law. We don't know where you are and it can vary from place to place so we can't even try to Google it for you.

Then again, if you think your P-Doc would lie to you, it sounds like you need a new one.

Or maybe you could just step on the scale? Do you know for a fact that your weight is going to be a problem?