Yes! I think it's an interesting plight, perhaps a question on the human condition - why do we, even when we're well aware that an action of ours will have negative effects later on, still carry out that action? If we weren't contradictory, imperfect beings, we'd all embrace the health habits we desire. I'd love to hear your thoughts on this too. Surely one reason behind this inconsistency is the pure gratification we experience from flavor (if only we didn't have such discerning taste buds...). It's truly a balancing act between the pleasure we get from food and the perils of unhealthy habits.
As for incentives, I think one of the missing links is the complete lack of hindsight for our actions—in other words, we don't really understand or experience the cumulative effect of our unhealthy choices until later on. Incentives, then, need to somehow bring the potentiality of these future repercussions into our present.