/fa/ - Fashion

Well, no.
Fat people cannot be /fa/. That however doesn't stop them to wear /fa/ stuff. By doing that, people will see you as a massive faggot (example: gay fat people like that fat guy from Modern Family). If that's how you want to look, knock yourself out. You can dress nice, however, but the "nice" clothes will just make you look like someone's tryhard dad or just as a massive faggot who just so happens to be someone's dad. Also don't listen to "style advice for big guys" they rarely work and you just stay fat.
You can be fat and considered /fa/, but only if you have a genuine /fa/ person or a whole /fa/ crew with you (example: A$AP Stevie ...pic). But you will always look like someone's sidekick, and without the crew you'll just look stupid and funny.

My advice: please lose weight. It's not easy (I know, I used to be a fat fuck myself), and it can't be achieved fast (took me about 2 and a half years). But the result is worth it. Try reading the >>>/fit/ sticky. It worked for many people (me too) and will probably work for you too (I say probably because I'm not sure if you will follow it the right way. If you do follow it the right way (obeying everything it says) it WILL work 100%).
In the mean time try dressing as simple as possible to achieve a "decent" look.

Godspeed!