At this point it would be useful to see a graph that plots obesity vs annual income of the caretaker(s) for a look at the social perspective. I can't seem to find the materials, but obesity and povery have been shown to be linked quite often.

Also, for the UK, the new rules, in wake of Jamie Oliver's show that outlined the poverty of school lunches, have taken effect only a few months - so any results will not be visible.

You've had your chips: fattening food banned from school canteens - Guardian

Chocolate, crisps and sugary drinks will be banned from secondary school canteens this month, under new rules to tackle childhood obesity.

The nutritional standards, already in force in primary schools, require a school lunch to contain at least one portion of vegetable or salad and a portion of fruit. School canteens will not be allowed to offer meals outside strict calorie limits, and must provide foods with a minimum level of iron, zinc, calcium and vitamins. Salt will be removed from canteen tables and foods that have too much fat, saturated fat and sugar will not be allowed.

Drinks will be limited to water, low-fat milk and juice. Schools have been told to use reduced-fat spreads rather than butter and to spread this thinly.

Meals that pass the new nutritional standards test include breaded fish, spicy fajitas, yoghurt and some cakes. The new rules follow a high-profile campaign by celebrity chef Jamie Oliver to improve the quality and taste of the country's school lunches.

Of course I can only be happy when, besides good nutritious food, children will be provided with free sport activities. Let's not just talk about food.