When POTUS lies about things that are easy to see, with our eyes, it just further enhances half the countries fears that an absolute megalomaniac liar is running the country. If he would be blatantly dishonest, and corrupt a medical doctor for his vanity, what else would he easily and clearly lie about?
I'll give Trump this; a ton of Americans are obese but are also unaware of it, so it's somewhat relatable on his end.
At least he didn't pretend to be one of the top ranked video game players in the world and Livestream himself being repeatedly killed by the tutorial boss before claiming "bad connection" and quitting.