It has to do with Whitaker being fat was one of the reasons Paul Newman didnt suspect him as a huslter. Plain and simple.
Whitaker just points it out.
Unless youre responding to me, dont hit reply on my post
I Emily Blunt

Brilliant line, one professional to another, off the record, on the QT and very hush-hush.

yes, amos had developed a certain character to help him carry off his hustle…part of that character was that he was worried about this weight….

No, it's not any of that. All of you are thinking too deep when it's very simple.Steveou said the correct answer.
Music is your only friend until the end.

"Weight" in pool also refers to changing the spot or giving advantage to your opponent to even things up.
Like telling someone "do you think I should go easier on you", while simultaneously reminding them the reason they underestimated you in the first place.

I think he was referring to the hustle character he had developed: A fat, non-threatening, sort of crazy-talking kid, whom no one would ever suspect of being a hustler.
In the end he sarcastically asks Eddie's advice: Would the hustle work better if he lost some weight? The answer is obviously no, since it worked so well on Eddie.
"Push the button, Max!"

The "hustling me" question was after Eddie had lost one hundred bucksthe "weight" question was after he lost four hundred.
A few games later
Fiery the angels fell, deep thunder rolled around their shores, burning with the fires of Orc

Amos (Withaker) said that line ('Do you think I need to lose weight?') one or two minute later than Eddie (Newman) asked if he was hustling him.
So while in your post it seems pretty straightforward, it is not at all in the movie. I'm not sure your answer is correct, but you're may be right about the screenwriter's original intention.

Great reasoning, and thanks. I didn't quite get it until I read your explanation. Sincerely; I'm not being flaky.

here is the answer to this.
Eddie was asking him 'are you hustling me Amos?'
him saying 'do you think I need to lose weight?' being the answer we would all say is 'yes'
That is the answer to the question eddie was asking him. he answered eddie's question by asking one of his own, which reveals the answer.

He was a flake just like Tom cruise was a flake. Newman wanted a flake that could be controled. But could not see that in the guy he lost to a little irony there no?

It has to do with the whole "character" thing. If you remember the scene when they are in the fine dining restaurant and Eddie tells Vince "you have natural character, you're a total flake people spend half their lives to perfect something like that" and "when you walk in a pool hall people will be climbing over each other to get a piece of you".
Well if you recall Amos kept talking about crazy things, giving off the impression he was off kilter, saying he was used as a psychological science experiment, etc etc. That last line about "do you think I should lose some weight" wasn't so much an insult but more a tell - Amos was tipping his hand that what you saw was a character built by Amos and he used it to fleece Eddie. Eddie was the mark. Amos was telling Eddie he suckered him, that Eddie fell for the 'character' Amos built and got taken down. Eddie learned from it (asking himself how he could fall for it, a little too cocky, a little too much booze etc) and sought to change himself.

Part of the reason FW was able to swindle Eddie was because of how he looked. A dumpy loser. But he wasn't. So by asking if he should lose weight, he was really just pointing out one of the things that worked for his con.
Movie Reviews
www.cultfilmfreaks.com
FBK
www.facebook.com/cultfilmfreakcinema

Now that's interesting! I never thought of that. Either way it's meant to be some sort of an insult to Eddie.
I never met a dame yet that didn't know if she was good-looking or not without being told.

I used to think that it was a reference to Eddie's games against Minnesota Fats in "The Hustler", but it might be a stretch to think that Amos would have known about that.

I always thought it was just a remark on his swindling of money.
Money buys food. Excess money busy excess food, excess food makes you overweight? I always considered it a slight backhand to Felsen because he got hustled.
I never met a dame yet that didn't know if she was good-looking or not without being told.