More than five weeks into the school summer holidays and do you know what I am sick of?

Not squabbles, queues, noise or that question I hear around 7am every morning: "What are we going to do today?"

No, what I am sick of is cones bulging with scoops of ice cream the size of a child's head. I am sick of wedges of cake that could hold open a door and biscuits with the circumference of side-plates.

There are an array of wonderful places to visit as a family in Scotland and across the UK. There are also thousands of little businesses catering for us in pretty cafes, which sometimes provide paper and crayons or play corners with pretend tills and plastic fruit and veg.

It is a pleasure to support them. I can throw together a picnic for a family of five in the time it takes most people to eat their breakfast, but I like a day off occasionally. When the sun is out what parent doesn't enjoy treating their children to an ice cream or sitting down for 10 minutes while someone else makes coffee?

But, I want to plead with all the vendors who have created such lovely havens – please make your portions smaller.

I thank you for your patience as my three girls, aged seven, four and four, ponder flavours. I appreciate your little jokes that make them giggle. But the experience takes a more stressful turn as I look up from picking a jumper off the floor to discover a "small" cone being handed over loaded with scoops of ice cream the size of a giant's fist. I then have to find ways to communicate over the heads of my other children – whose eye's are glinting with expectation – that you should give them less. Or I end up forcibly removing the cones from their sticky fingers three-quarters finished. (I might sound paranoid but it is not just obesity I am worried about – one twin has a tendency for car sickness.)

I'm neither an accountant nor a chef, but as far as I can see it sensible portions are a win, win, win. You use up less stock, I'm a happy customer, my children are delighted and more likely to remain slim.

We all know people have got fatter and that it really isn't good for them. In the latest Scottish Health Survey girls were more likely to have a weight issue than boys. The proportion of girls at risk of being overweight or obese was 34 per cent in 2014, up from 27 per cent in 2013.

Experts are keeping a close eye on this trend – but they won't be able to change it. That's down to parents and all those who sell food aimed at children. We spend a lot of time attacking the big players in the food industry and telling mothers and fathers what to do but for me this summer it has been nice people in nice places who have upset the balance of our family diet and ruined what should have been a treat.