It's not the junk food adverts, it's the parents. Sharon Griffiths says we must take responsibility and give our children healthy meals.

Six year olds don't have bank cards. Five year olds aren't made of money. And two year olds can't even push the trolley in a straight line.

So how come they're doing the shopping?

We have an obesity crisis among children. A third of children are too fat by the time they leave primary school. Too many are wobbling their way to a depressing list of likely illnesses followed by a probably early grave.

Of course it's the parents' fault. It's not the toddlers who are paying out and lugging the shopping home.

True, parents are fighting a massive battle against the billions that multinationals pour into forcing junk food into our children. All those ad campaigns! All those tempting displays!

All the pressure of global persuasion beating down on every harassed parent in a supermarket aisle. It's not always easy to resist.

My children certainly rubbish occasionally because it was quick and easy and kept them quiet. They'd seen the ads. They knew what they wanted. A generation later I've been known to give in to a toddler pleading for My Little Pony cup cake mix. The cartoon cup-cake mixes, incidentally, are displayed on the bottom shelf of baking goods – just where a child can spot them. Shame on you, Sainsburys… but it's still my fault for letting her choose them.

After plans to tackle childhood obesity were ditched some time ago, they are apparently back. There's the tax on sugary drinks plus plans for bans on junk food deals, early evening advertising and endorsement by celebrities or cartoons.

It's all admirable. It could all help.

But the real solution is much simpler - if parents didn't buy the rubbish in the first place, then children wouldn't be able to eat it.

It's not just junk food. Too many of us, adults and children, just eat too much, full stop. Even healthy food isn't that good for you if you eat twice as much as you need. (Definitely my problem.) But we've lived in a land of plenty for too long. For most of us, food is easy and effortless. Rationing is becoming a folk memory.

'Good grief!' said my mother once watching me make scrambled eggs, 'There's nearly a whole week's butter ration in that pan!' But who now remembers what the butter ration was? Today we have a completely different relationship with food.

Add to that parents who now find it almost impossible to say 'No' to their children and we've created a monster situation.

So good luck with all those campaigns. They need to educate the children. But first, they have to start with the parents.