Public Health England said that half of children’s calorie intake is coming from sugary treats and drinks.
On average each child has at least three treats a day. Over a year they munch through 400 biscuits, 120 cakes and pastries, 100 portions of sweets, 70 chocolate bars and 150 sugary juices or cans of pop.
This leads to them consuming three times more sugar than recommended. A third of UK children leave primary school overweight or obese.
A new Change4Life campaign on snacking is now encouraging parents to “look for 100 calorie snacks, two a day max”.
It aims to promote healthier snacks and will offer parents special offers on a range of them, including fruit and vegetables at selected supermarkets.
Fresh or tinned fruit salad, chopped vegetables, lower fat hummus, crumpets and Scotch pancakes are among the snacks they recommend.
PHE said its new advice applies to all snacks apart from fruit and vegetables, as children should still be encouraged to eat a variety of these to achieve their five a day.
“The true extent of children’s snacking habits is greater than the odd biscuit or chocolate bar," said Dr Alison Tedstone, chief nutritionist at PHE. "Children are having unhealthy snacks throughout the day and parents have told us they’re concerned.
“You see children buying chips coming out of school and buying a bag of chips on their way home from school, and that’s part of the reason why we have an obesity epidemic in this country.
“To make it easier for busy families, we’ve developed a simple rule of thumb to help them move towards healthier snacking – look for 100 calories snacks, two a day max.”
Dr Tedstone added that with an average ice cream containing around 175 calories, a packet of crisps around 190 calories, and a pastry around 270 calories, the amount eaten throughout the day by children and adults alike can add up.
PHE is working with the food industry to cut 20 per cent of sugar from the products children consume most by 2020.
The recommended calorie intake for children boys aged seven to 10 is 1,970 calories per day, and for girls, 1,740 calories per day. This rises 2,220 calories per day for boys aged 11 to 14 years and 1,845 calories per day.
Justine Roberts, chief executive and founder of Mumsnet, said: “The volume of sugar kids are getting from snacks and sugary drinks alone is pretty mindblowing, and it can often be difficult to distinguish which snacks are healthy and which aren’t. This rule of thumb from Change4Life will help parents make healthier choices, which can only be a good thing.”
The campaign, which features a TV advert created by Aardman Animations, will run across England from Tuesday for eight weeks and will see parents offered money-off vouchers for healthier snack options by signing up to the Change4Life website.
Additional reporting by PA