Fat is bad and everybody knows it.
Ugly is bad and everybody knows it.
Poverty is bad and everybody knows it.
Powerless is bad and everybody knows it.
Skinniness is bad and everybody knows it.
Being a nerd is bad and everybody knows it.
Being uncoordinated physically is bad and everybody knows it.
Being less abled physically (blind/deaf/etc.) is bad and everybody knows it.
Being uneducated is bad and everybody knows it.
Having a small dick or small breasts or a flat ass is bad and everybody knows it.
Being tone-deaf is bad and everybody knows it.
Being mentally ill is bad and everybody knows it.
Having a chronic disease like HIV or Multiple Sclerosis is bad and everybody knows it.
Being gay or bi is bad and everybody knows it.
Objectively, it's difficult and sometimes inconvenient and sometimes disadvantageous to be "different," to be "other." But, most of what we see as "negative" or "bad" about something is usually (a) incorrect, (b) highly limited in scope, and (c) mere prejudice.
In some contexts, these things are "not so bad" or "ok" or "even positive."
The character of the observer and the character of the observed.
I have a reasonably good body and a reasonably good face and am often complimented on my looks or cock or something, and almost everyone is impressed by my mind and my ability to articulate my thoughts.
BUT, I wear thick glasses, have teeth problems, have physical problems that people don't easily see but often comment on, too, using generalisms.
Ignore those people because they do not create your reality.
Remember when you came out of the closet? You were terrified that you would lose your friends. Then almost everyone was cool. And the few that were not cool you were able to move away from because you understood that they were NOT TRULY YOUR FRIENDS. Had they been your friends, they would have loved you, would have done some research and would have changed their perceptions of you and, in general, of all gay people.
We all know disgusting fat people. Or gay guys who are assholes. Or uneducated people who are so fucked up it's impossible to be around them. BUT, in most cases, the problem is not the obesity or the gayness or the lack of education. It is other behaviors associated with that particular person and we blame the obvious characteristic (the fat or the homosexuality).
Ignoring majority prejudices is silly. They affect us. Ignoring objective problems with chronic diseases or eyesight problems or obesity is silly. They affect our health or comfort or ability to function.
But that's not why people comment insensitively about our "problems" or "flaws" or "differences." They comment insensitively because they themselves are deeply insecure and uncomfortable and unkind.
So, ignore them. Not because you're ok. You might not be. But because their comments do not come from a desire to help you, but rather from a desire to superficially and falsely repair their sense of insecurity, discomfort and unkindness. They don't matter. Never judge yourself by an asshole.
When someone makes a homophobic remark around me (or to me), I immediately walk up to them (stranger or acquaintance) and quietly (but loudly enough for their peers to hear) say, "What you just said about gays being [blank] was unkind and merely demonstrates that you're feeling very insecure. What is it about you that you hate so much?" Almost always their friends begin to mock the homophobe.
If you want to lose weight to be healthier, ok. But realize that there are risks to working out, to losing weight, to being "perfect", to being attractive, to being ANYTHING.
Be ok with who you are.
By the way, if you've read this far: I'm 52 and dying of cancer. I've been a university professor and am now "retired." Lots of mistakes in my life. But, all in all, not a bad life. Do you know what matters, I think, in the entire world, above all else? Only one thing: KINDNESS. Little tiny acts of random kindness.