This is basically Scott Adams's "Pleasure Unit Theory", which I find very plausible: http://pratie.blogspot.com/2006/04/scott-adams-pleasure-unit... . If it's true, then developing healthy food that's convenient and tasty will do a lot more good than hectoring people about their bad decisions.
We can't fix everyone's problems. Hectoring may be bad, but at the end of the day a lot of change has to come from the people making bad decisions. Sacrifice for ones children should be the norm, otherwise they shouldn't be bringing them into such a suffering existence.