Unit 1: How to reduce consumption of "unhealthy" food?

The BBC and Sky report a new initiaive from the government

http://www.bbc.co.uk/news/health-12104278 BBC video
http://www.bbc.co.uk/news/health-12099867 BBC article

http://news.sky.com/skynews/Home/Politics/Food-Vouchers-From-Mars-Nestle-Asda-Weight-Watchers-And-More-To-Encourage-Healthier-Eating/Article/201101115877805?f=rss

a) To what extent do you think this initiative will reduce the negative externalities associated with the excessive consumption of high fat/sugar/salt foods?