Most of my life, I've worn fat girl pants. These are essentially polyester (blend) stretch pants which, unfortunately, seem to highlight every bulge. You have to choose them mainly because things like blue jeans rarely fit right, and then you're squeezing your bulges in very uncomfortable ways. Also, frankly, you don't look any better in non-fat-girl pants than the stretchy kind anyway, and there are more sizes of stretch pants than other types.
When I was growing up, I hated shopping for clothes because fat girl pants were always unfashionable. My mother also loved to buy a variety rather than allow me to try and mask some of my unsightly body with black, black and more black. She'd come home with light blue, red, or, even worse, pink. There's nothing like being fat in pink polyester stretch pants to make you feel like a million bucks. :-p
The good point of fat girl pants is that they stretch so that, if you gain more weight, you don't need new clothes. This is also, coincidentally, the bad point. You can be putting on weight and not realize it until they start to crawl lower down your belly and back as your expanse fills more of the available space.
The main problem with fat girl pants and my approach to checking on my weight loss progress at this point (which is by look and feel rather than using the scale), is that stretchy pants aren't likely to change much with weight loss. Right now, my pants mainly show my weight loss by getting longer as the bulk that held them up to ankle length disappears and they get slacker. Come winter, I'm going to have to hem all of my pants. That being said, even my stretchy fat girl pants are starting to bag a bit in spots so I see that as a good sign.
I've got one pair of non-stretchy pants from when I lost about 50 lbs. about a decade ago. Before I started on this journey, they couldn't be pulled over my thighs. Now, I can actually get them on, but they are tight and I'm sure they'd split a seam if I tried to sit in them. Nonetheless, the fact that they can be put on at all is a sign of progress. Once I lose a fair amount of weight, I'm thinking that I should not buy fat girl pants anymore as they actually may contribute to weight gain by being able to easily accommodate increased girth.