It's probably already caught up to you more than you know - depending on how tall you are, and your level of physical fitness that might only be slight obesity - or gross obesity.
The damage that smoking does is so incremental that you usually don't notice as you have less lung capacity, which translates directly to less physical capability - in addition to the other problems that nicotine (and the countless other chemicals in cigarettes) cause.
My suggestion is to take three cigarettes out of a pack and put them someplace warm and dry. Get a pipe and some tobacco, and when the urge to smoke hits, pack the pipe and take a few puffs (you don't actually have to inhale - as it is much stronger).
Do this for a few weeks - and if, at any time, you feel an overwhelming urge to smoke cigarettes, go find the cigs you put out, which will be stale by that point - and hotbox them until you throw up.
Weaning yourself off the pipe is much easier - as it is harder to just whip out and light up.