Trump

The definitions tend to suggest a disorder where people suffer from an unreasonably high sense of their own importance. I think the unreasonable test fails in this case.

I would suggest that is being rather selective in your definition, or rather selective in your choice of partial definition - to the extent of misrepresenting or possibly misunderstanding the meaning.

Now, I know that if you type in "narcissism" into Google, the top hit is the mayo clinic which starts with...."...a mental health condition in which people have an unreasonably high sense of their own importance...". Which is word for word for what you posted. However taking that one sentence rather fails the "only scraping the surface" test of its meaning. 

Lets take a deeper dive:

"Narcissism is a self-centered personality style characterized as having an excessive preoccupation with oneself and one's own needs, often at the expense of others."
"excessive interest in or admiration of oneself and one's physical appearance."

As single sentence encapsulations, these are far more representative of the meaning. Lets expand a bit further:

"Narcissism is extreme self-involvement to the degree that it makes a person ignore the needs of those around them. While everyone may show occasional narcissistic behaviour, true narcissists frequently disregard others or their feelings. They also do not understand the effect that their behaviour has on other people." 

Note that all of these focus on the self-centred aspect, because of course one can be very important and know one is very important, while still not being a narcissist. Obama, Biden, Bush etc. were all very important, and I'm sure they recognised that. However that didn't make them narcissistic, because they still had empathy for others and recognised that their needs were not to the exclusion of others. It's the reasonableness of the fixation on self that is critical.

Back to that Mayo Clinic opening line. Click through and read, and you get less (somewhat misleading) surface and more depth. For example:

"People with this disorder may lack the ability to understand or care about the feelings of others. But behind this mask of extreme confidence, they are not sure of their self-worth and are easily upset by the slightest criticism."  Umm.

Read on a bit:

Symptoms of narcissistic personality disorder and how severe they are can vary. People with the disorder can:

0 Have an unreasonably high sense of self-importance and require constant, excessive admiration. TICK
0 Feel that they deserve privileges and special treatment.  TICK
0 Expect to be recognized as superior even without achievements.  TICK (not because of no achievements, but claiming ones that weren't or weren't his) 
0 Make achievements and talents seem bigger than they are. TICK (4 bankrupt casinos from the stellar businessman anyone? )
0 Be preoccupied with fantasies about success, power, brilliance, beauty or the perfect mate. TICK (I got bored with the bracketed examples bit)
0 Believe they are superior to others and can only spend time with or be understood by equally special people. 
0 Be critical of and look down on people they feel are not important. TICK
0 Expect special favors and expect other people to do what they want without questioning them. TICK
o Take advantage of others to get what they want. TICK
0 Have an inability or unwillingness to recognize the needs and feelings of others. TICK
0 Be envious of others and believe others envy them. TICK
0 Behave in an arrogant way, brag a lot and come across as conceited. TICK
0 Insist on having the best of everything — for instance, the best car or office. TICK

I think Trump passes the "are you a narcissist test", In fact I think he probably "aces it": rather like that apparently "hard" cognitive test that he keeps bragging he "aced", even though it seems it was a basic standard seniors cognitive test: perhaps see fourth bullet point above).

There was a bit in Private Eye about Ozempic and journalists writing about their "journey" over and over again. But it turned up a couple of good quotes. One journo found one where Barbara Cartland said something along the lines of "You have to choose between the face and the figure darling, and nobody minds a bit of padding". In the second one the journo said "I am moderately overweight but nothing I would dream of bothering the doctor about. I have a slight feeling of resentment at these people taking a short cut". 

Definitely.

Photos of Trump standing next to other people, full length, with anything as context, seem to be few and far between...

Obama is officially 6'1 1/2". Obama was clearly slightly taller than Trump at the 2017 inauguration...
 

I might not be a fan of DJT myself. But according to Dr. Jean M. Twenge, a psychologist known for her research on narcissism, narcissists can offer a sense of excitement and validation, as their grandiosity and attention can make women feel uniquely special or admired.

Additionally, women with lower self-esteem may be particularly vulnerable, as they might interpret narcissistic behaviors as a sign of value or superiority.

I suppose for those who don’t know how to love themselves, it’s harder to show the love language to their recipients.

but you didn't quite: You used the first sentence without the context of everything else they said. The complete first paragraph is:

"Narcissistic personality disorder is a mental health condition in which people have an unreasonably high sense of their own importance. They need and seek too much attention and want people to admire them. People with this disorder may lack the ability to understand or care about the feelings of others." (My italics for the additional bit). 

And then of course they go on to list all the symptoms which define the condition, a list I repeated for convenience in the above. Since it is a condition which is defined by its symptoms, I think we can say he easily fits it. 

Well, both 45th and 44th POTUS heights were examined by the same White House physician Ronny Jackson

According the records, Obama’s height is 73.5 inch and DJT is 75 inches.

www.nytimes.com/interactive/2016/03/08/us/politics/document-president-obama-medical-exam.html

time.com/5104183/donald-trump-health-ronny-jackson/

No idea if Adrian has edited to photo or not, but I think DJT cannot stand naturally very straight making him looks level in some photo at certain angles.

Weight wise, he might just keep his 4 stables in his Trump Force One and not much weight loss.