I have lost weight in the past, and regained again. It is a terrible cycle. But even knowing that, I would give them away. You will be helping someone in need (it is hard to have money for new, decent work clothes.) Even I don't buy new clothes. Relying mainly on thrift stores and super sales. You won't ever use these clothes again. Just do it, you never miss them.

(and you can always keep a few if you wished)

Congrats BTW, when do I get to see the new you?