When I was young................I have resisted saying that for so long........... kids were skinny. I was skinny, my school mates were skinny with 'The Prof' (professor) being the exception. He suicided recently I have learnt. Clever, but short and fat. I suppose there was a couple of big blokes, not fat, just big. But for most of us if we were asked in science how many ribs does a human have, we could readily come with an answer.
I am a bit of a people observer and I have observed that many school kids now are not exactly slim. The school kids I see are mostly of the private variety, so from social statistics, they should have a reasonable diet, but no, they are either fat or potentially fat. There are very few skinny kids. Even the skinny Asian kid is disappearing.
Something has gone awry. Generally you should only get fat as you age. Is it diet related? Perhaps to a point, but our school canteen did a good trade in sausage rolls, jam donuts, lollies and sweetened flavoured milk.
There was a phrase often heard, 'he's got hollow legs', meaning that there was not an obvious sign of the huge quantities of food consumed. He must store the food in his hollow legs.
The conclusion must be that insufficient energy is being expended compared to the energy being consumed. I don't think deliberate excercise is the answer. That sounds boring to kids. It sounds boring to me. No, kids have to do what kids used to do, play, walk, cycle, climb trees, wrestle, build stuff, wreck stuff, chase each other. It can't be easy being a parent now.