Things got really weird when Lucky Strike forced viewers to imagine their future fat butts on a horse. Not only is the horse bogged down with the weight of a thousand Depression-era snacks (aka apples), but it's losing a race to the "prettier" skinny version of the same person. Look at the first half of the skinny model's horse leap like it's made of air! Notice how its backside is probably not going to clear the fence, which is also a good metaphor for the lung health of a long-term smoker.
Of course, Lucky's "Don't Be Fat" campaign ran in the 1930s, when women were barely out of the house and only months beyond their liberation from knee-length hair. So you can understand the mindset behind displaying looming jelly shadows as examples of what not to be. Advertisers didn't know any better. But you'd also think their granddaughters would move on to better things 30 years later. You'd be wrong.