So I'd like to see all the evidence before passing judgement.
Economists have shown (
afaik) that people do react to such incentives and do change their behaviour. In which case, it would be a perfectly apt use of public funds as you can calculate the 'gains' from not having to spend money later on on people sick because of smoking/unhealthy eating habits. It may be patronising but telling me to stop at a red light could similarly be construed as patronising.
OTOH, I am reading a book by Martha Beck (the 4 day win) about dieting (I am trying to lose some weight) and she says that such infantilisation/reward cycle will trigger unconscious rebellion so that, while a conscious/will-based approach may succeed in the short term, it will eventually lead to a backlash where people binge incontrollably and end up worse off...
She quotes a study (which I cannot find right now) where some men with a balanced lifestyle and good mental attitude were suddenly put on a strict diet - Slowly but surely, these men went bonkers, binging etc. Even after the study was finished, their relationship to food had been warped and they suffered the scars for a long long time...
Her point is that overweight people usually know that they should eat less and move more. The problem is that they cannot stick to the program. And that's not a question of willpower. It's a matter of them using food as an emotional palliative for a lot of things. Other people would bite their fingernails. Or smoke. Or drink. Or wash their hands compulsively. The point is that overeating has nothing to do with being hungry. Thus, the secret of losing weight (according to Beck) lie in controlling your stress/unhappiness and not using food as a destressor.
If she is right, then, putting added stress with cash reward will backfire in the long term.