I had a pullup bar too when I was young, I got my back to ridiculous shape by doing a few pullups every now and then. Like people were surprised - I do pushups like a geriatric paraplegic, then go to a pullup bar and do a set of 20 with perfect form.

And yeah, people went “oh you lost a bunch of weight!” When I said “naaah I eat the same live the same”. Then I stepped on the scale and wow.