The Observer, Sunday 4 January 2004 :

A study comparing the weight and growth of pupils fed on a 1940s diet with those on a contemporary menu rich in junk food underlines the growing concern over obesity levels in Britain's youngsters. The current generation of eight-year-olds consumes on average 1,200 calories a day more than their counterparts 60 years ago.

In addition, those fed on wartime rations grew significantly taller while shedding substantially more weight compared to those on a modern diet of school meals and packed lunches.

Professor Philip James, head of global think-tank the International Obesity Task Force, said children were far healthier during the war than now, when the choice of food has never been greater.

Greater choice does not necessarily lead to better choices. It's the selection criteria and one's ability to follow through with it that makes all the difference.

Also see Nudge, by R.H.Thaler and The Time Paradox, by P.G. Zimbardo.