This old ad is funny because it suggests that smoking is healthy, but the point is quite real, smoking does indeed work to help lose weight:
It's toasted: You would have to be toasted to take-up smoking to lose weight
I quit smoking 18 months ago, and I can attest that the physiological effects of smoking do indeed reduce hunger.
You can physically feel your blood vessels become restricted, and hunger pangs disappear.
There was an old term “smoke your lunch” and smoking remains popular among anorexic models and ballerinas who must stay super thin . . .