One of the big villains in the excess consumption of carbohydrates is consumption of sugar via soft drinks and fruit juices. There is reasonable evidence that soft drink consumption is associated with childhood obesity. One sugary drink per day among women is claimed to increase their chance of contracting diabetes by 80% - although, guess what, the soft drink industry reject this. These results are replicated in many countries. Excess sugar consumption is primarily a problem of developed countries but developing countries (like India) are catching up quick.
Australian kids gain significant amounts of their daily calorie intake via soft drinks. The intake of soft drinks in Australia has grown rapidly in the past 30 years from around 47.3 L per person per year in 1969 to 113 L per person (children and adults) in 1999. While this is below the per capita consumption of 200 L per year in the US it does put Australia within the top 10 countries for consumption.
Victoria has just banned the sale of high sugar soft drinks in its 1,600 public schools from next year. The sale of fruit juices is encouraged as a substitute. The rationale is that the consumption of even a single bottle of soft drink more than exceeds the recommended intake of calories from sugar per day for a 14 year-old child. Irrespective of whether this nutritional objective is sound or not (I think it is sound) if the objective is to reduce sugar content the proposed ban might help but probably not by much.
At lunch today I bought a 600 ml small Coke. Its sugar content per 'serving' (defined to be 200 ml) was 21.2 grams. But I don't ever recognise people drinking 1/3 of a small coke. They typically scoff the lot so in fact they get 63.6 grams. This is equivalent to 8 teaspoons of powdered sugar or over 15 teaspoons of sugar from a sugar bowl. By the way, I didn't drink this rubbish - I poured it down the drain!
My friend John bought a healthy Just Squeezed Orange Juice in a 300 ml container. The 'serving' size is now more honestly taken as 300ml which contains 21.3 grams of sugar. 600 ml of this healthy drink contains, yes, 42.6 grams of sugar. This is equivalent to 10 teaspoons of sugar from a sugar bowl.
If people substitute from soft drink to the bottled juices there is some saving in terms of sugar consumption but not much. The Coke will be banned in public schools, the bottled juice won't be though it too is laden with sugar. Better advice would be to drink water when you are thirsty - from a school tap it has the additional advantage of being free.
In my view the objective of cutting sugar intake among school children is sound. But I am not sure this measure will do it since it focuses on soft drinks not sugar content.
Remark. Why the Coke 'serving' size labelling? For a 600 ml Coca Cola Zero (the low sugar variant) the 'serving' is 600ml while for Coke with sugar it is 200ml. Is Coke's manufacturer hiding the huge sugar load of a bottle of ordinary Coke? And the label on the Just Squeezed juice reveals the juice is 'reconstituted'? Does this mean the same as 'just squeezed'?