21/10/2015 13:46 BST | Updated 21/10/2016 06:12 BST

Sugar-Coating a Bitter Truth - High Street Restaurants Are a Calorie Catastrophe for Kids

It's not always easy to make healthy choices when buying food for your family. Supermarkets have started to tackle the dreaded sweet display at the checkout, but high street restaurants continue to peddle children's menus dripping with sugar.

The Soil Association's Out to Lunch campaign has worked with an army of 'secret diner' parents to investigate the quality of food on offer in 21 top high street restaurant chains. We found a number of chains marketing kid's menus with shockingly high sugar content.

With 40% of families eating out more than twice a month, restaurants should be making life easy for parents who want their children to enjoy a healthy treat, but the reality is often very different. As one parent explained: "The puddings were all sugar. The drinks were all sugar. The puddings were promoted on the table, like an ice-cream candy shop. I was on my own with three children - what do you think happened next?"

Let's start with Pizza Hut, where children are offered an unlimited 'ice cream factory' with do-it-yourself decorations. Sugar is offered in a variety of forms: glucose syrup, glycerine, dextrose, caramelised sugar, molasses, and invert sugar syrup are all on the menu, with the 'ice cream factory' providing kids with the opportunity to mix these up with cocoa butter, palm fat, pork gelatine, and 18 different E-numbers.

A single portion of 'ice cream factory' ice cream, topped with lemon crunch and milk chocolate beans contains 109g of free sugars. This is 27 sugar cubes - 450% of the daily sugar allowance for a child of 10. "Pizza Hut is the perfect place for family fun" the website boasts. Pizza Hut is the perfect place to get your children tanked on the white stuff.

And they don't stop there. Pizza Hut, Café Rouge and Frankie & Benny's promote free or discounted refills of sugary soft drinks on their children's menu. A single can of Coca-Cola will max out a child's sugar budget. Most parents would agree that one is probably enough - these chains apparently disagree.

At Nando's meanwhile, parents are supported to make the healthy choice with a nifty calorie calculator, available online or as an app on your smart phone. This is fantastic for calculating the sugar content of your fried chicken. It's less useful when applied to your drinks - refillable soft drinks, available at Nando's, are excluded from the calculation. This is a calorie calculator that leaves out the most calorific item on the menu.

Perhaps the restaurant chains are not entirely to blame. In the course of our investigation one well-known chain told us that they were tied into a contract with a soft drinks supplier requiring them to offer unlimited refills to children - they could do nothing to stop this until the contract expired. Even more concerning, they suggested they were also restricted in their capacity to offer free tap water to families upon arrival in the restaurant.

This is extraordinary practice in a country where a fifth of children joining primary school are obese or overweight, where 26,000 children had to have rotten teeth removed in hospital last year, and where 135 people are having body parts amputated because of diabetes each week.

Cutting back the sugar does not mean eliminating the fun of eating out. A small group of chains are showing how it's done. Harvester has swapped sugary soft drinks for no added sugar options and has made water freely available to families. Wetherspoon's - serving close to a million children's meals each month - offers a fresh fruit pudding with every kid's meal. And Jamie's Italian has introduced a 10p duty on sugary soft drinks sold in restaurants, with the money raised spent on children's food education in the UK.

France has gone one step further. At the beginning of April, the French National Assembly voted strongly in favour of a healthcare law amendment that would ban self-service soda fountains and free refills of sugary soft drinks in restaurants.

Our Government should follow the French example and send a clear message to restaurant chains that piling pounds into pockets by piling pounds onto waistlines is simply not acceptable, and that action must be taken to ditch the sugary drinks and include fruit-based pudding options. It's time that high street restaurants cleaned up their act and prioritised our children's health.

The new Out to Lunch league table will be launched on Wednesday 21st October

What do you think of kid's menus? Let @SoilAssociation know using #OutToLunchUK