Chronic smoker here. 7 years and counting. Throughout these years, I haven't had a week straight 3 course meal. Just 1 meal enough to survive the day or two if I'm not lazy. 105lb is the minimum weight, and I won't lose anymore now, nothing else to lose. Went visit my relatives for 3 weeks, and ate normally for 3 weeks, and didn't smoke until the last day I left. Ended up weighing 121lbs, and was my highest weight. Shrunk back to 105-108lbs, when I got back home - Not instantaneously lol . Not eating right, working a lot, stress & responsibilities that shouldn't be on you takes a tow out of you.
My Younger brother, just by one year is weighing about 198lbs, isn't a chronic smoker. Every time he visits, he gets bigger and bigger, and now hes losing weight, as I got him a job, which involves moving around a lot.
Conclusion: It was the drugs! More on cigs & weed.