By Emma Clayton

You only have to walk past your average fast food eaterie for a chilling vision of the future.

It's not unusual to see infants scoffing their body weight in nuggets and fries, washed down with huge cartons of pop that might as well be bags of sugar.

NHS England chief Simon Stevens claims that nearly one in five secondary school aged children are obese, up from 15 per cent 20 years ago. Unchecked, this will lead to a huge rise in illnesses like type 2 diabetes which already costs the NHS an estimated £9 billion a year.

Are free school meals the answer? Baroness Floella Benjamin thinks so. The chairman of the All-Party Parliamentary Group on a Fit and Healthy Childhood wants the Government to give all children free school meals, as part of a "national nutrition strategy".

But the introduction of universal infant free school meals last September means all reception to Year 2 primary schoolchildren already have a healthy, nutritious lunch. Why should the tax-payer fund free lunches for every child throughout their school life, regardless of parental income?

Perhaps a more effective way of tackling childhood obesity would be to test the fitness of schoolchildren in the same way as other subjects.

Health organisation ukactive says the recording of children's fitness in primary schools is "rare and at best sporadic", with fewer than half the schools surveyed tracking the time children spend actually being active in PE lessons, excluding the time spent getting into their kit.

Its Generation Inactive report warns that the nation is facing a "ticking timebomb" of a physical inactivity pandemic, with only half of seven-year-olds meeting the Chief Medical Officer's guidelines of 60 minutes of daily physical activity. While it would be considered unacceptable for pupils to leave primary school without their parents and teachers having a basic understanding of their ability in maths and English, it's normal for them to not have the same understanding of their fitness levels.

The report recommends a "whole day" approach to physical activity by incorporating it into lessons, with fitness and health measured in a fun, inclusive way. One school has "Kung Fu punctuation" in English lessons, with children making Kung Fu style hand movements to signify where an exclamation mark or full stop should go, rather than simply raising their hands.

Chairman of ukactiv, Baroness Tanni Grey-Thompson, puts forward changes as simple as children standing in lessons and developing more structured use of playtime. Rather than focusing solely on PE lessons, she says a 'whole school approach' could help towards achieving the 60 minutes of daily activity.

It has become worryingly normal to see overweight children - whereas once there may have been just one or two in a class, standing out like sore thumbs – and it seems they're slipping through the net in schools.

Boosting physical activity in a fun, holistic way, and testing fitness levels alongside academic progress, has to be worth a shot. We owe it to the increasing numbers of children living largely sedentary lives, who are at risk of turning into a generation of poor achievers with high rates of depression and physical illness.