How many calories does a cigarette burn?
I really dont know how anyone could estimate a value for how much energy smoking a cigarette takes up, but its sure to require some – mainly as you said from the detoxification process afterwards. The toxic products produced from smoking would potentially have to be metabolised by Phase I and Phase II metabolism enzymes in the body, which require energy in the form of NADPH, NADH and maybe some other compounds, which the body has to make from respiration.