Health campaigners have called on the next government to extend the soft drinks levy to confectionery containing the highest levels of sugar.
Chocolate and sweets are already included in Public Health England's (PHE) programme aiming for a 20% reduction in sugar by 2020.
But Action on Sugar is urging a mandatory levy set at a minimum of 20% on all confectionery products that contain high levels of sugar, including those sold in coffee shops and restaurants, to help tackle the obesity and Type 2 diabetes crisis.
A two-tier levy of 18p on drinks with 5g of sugar per 100ml and a higher 24p rate on those with more than 8g per 100ml will be introduced from April 2018 as part of plans to reduce childhood obesity.
Chocolate and sweet confectionery contributes 9% of the total sugar in the diets of children aged between four and 10, and 11% in teenagers, according to PHE figures, but contains little or no nutritional value and contributes significantly to tooth decay.
Action on Sugar chairman Graham MacGregor said: "The levy should be structured by HM Treasury as per the soft drinks industry levy, whereby it is aimed at manufacturers to encourage them to reduce sugar in their overall product ranges.
"Any revenue raised should go towards improving health in the UK."
The campaign group said the next government needed to introduce tough measures to ensure compliance and "put public health first before the profits of the food industry".
It also urged PHE to launch a calorie reduction programme imminently to reduce both sugar and total calories, warning that voluntary sugar reduction through reformulation alone would not combat obesity.
Action on Sugar campaign manager Jenny Rosborough said: "Although Public Health England does not recommend that confectionery is eaten as part of a healthy diet, these foods are one of the biggest contributors of sugar to the diets of children.
"The government obesity plan must be revised to include tougher measures to ensure these products are not heavily marketed or promoted and that the manufacturers produce healthier versions with fewer calories."
World Cancer Research Fund head Caroline Moye said: "Around 62% of UK adults are overweight or obese, putting them at an increased risk of many different health conditions, including 11 common cancers.
"In fact, around 25,000 cases of cancer could be prevented ever year in the UK if everyone was a healthy weight.
"If the next government tackles this health epidemic with serious, multi-faceted policies it will create a legacy of a healthier society for generations to come."