I am with schattenjaeger. There is definitely a correlation, but I feel they have missed the cause.

When trying to heal someone of their vice, smoking or eating or drugs, it is too easy to end up with the person just switching one vice for another. Quitting Smoking in particular, easily leads to overeating. The root cause is usually emotional and usually based in trauma (from childhood). If you don't fill that hole in their heart, one vice shunned, will just lead to another.