Did any of you ever purposefully(or unintentionally) gain or lose weight in order to pass better or to at least help hide the sexual characteristics of what you were assigned at birth?

I'm wondering for two reasons:
       When I was younger, I thought about trying to make myself fat because then it would just look life I had serious manboobs from being overweight. I never went through with this, thankfully.
       I've always been naturally skinny, but since I've been having some natural hormone issues, I partially got a few secondary male sex characteristics. When my brother hit puberty, his face began looking much more angular and his cheekbones became more prominent. When the weird stuff I was having, my face changed (to some extent) in the same way as my brother's. However, my mom thinks that my cheekbones looking more prominent is a sign that I am not eating enough, even though I'm at the healthy average weight for my age/height and actually have been slowly gaining weight.

So, have any of you ever changed your weight because of being trans-something?

I've never changed my weight in order to pass better...but not for a lack of trying. I have a high metabolism so I don't gain weight all that easy anyway...I have definitely thought about it though. If I were bigger, then I could act like these things here (Breasts) are just due to being overweight..but then again, I know that's a bad way of thinking. After a bit I thought about it and thought, why trade one physical hurdle for another? So, I stopped trying.

From a girl view I deliberately always kept my weight down, I even under ate as a teen when T was poisoning me and generating male muscle and need heaps of food. I took up running to keep thin and I never did any weight work. It sort of worked, I'm about 5'8" and 60 kilos.
I use to get  (at school) you are so amall you look like a girl. Which was fine by me

Cindy

I was anorexic as a teenager - until I got put on steroids to cure something I didn't have, and put on 10Kg in 2 weeks . Right now I'm trying to lose some weight to reduce my middle-aged belly, while I wait to go on HRT.

yeah, losing weight and putting on muscle. Training with weights and such.

I was anorexic for many years, but the worst of it occurred after I learned that low body weight reduced testosterone.  Within two months, I was 100 pounds (at 5'11").  Not sure if it ever lowered my testosterone but my low body weight might very well have been the cause of my infertility.  I had every intention of banking sperm at the start of HRT only to find out there was nothing there.

It's been about a year since I found that out and I still struggle with the knowledge that it was my own damn fault.

 I have. I've been overweight for most of my life, not severely,  but like a Seth Rogan type of big, and aside from boobs, I hate it. I've tried everything I can think of to lose weight, good and bad, all in the name of looking more "passable", and it never stays off. I love food. repeat : I LOVE FOOD! I like everything bad, burgers, chips, pastries, fried stuff... and eating has become a method of comforting myself.

The times I dropped some weight I felt like I was much, much more feminine looking, whether it's true I don't know, but I would love to drop a buck fiddy.....

I want to gain weight because I feel frail and too thin. I love to eat, I have absolutely no issues with eating. Food is one of the things I love more than anything else in the world. But I just have not changed weight in about 6 years. Maybe I could gain some muscle on my arms and legs and shoulders if I work out, but that's not going to change the rest of me.

FYI I am 5 feet 3 inches and I weigh around 105-110 pounds. I've been told that is a normal weight but I still really hate it.