The Swiss food giant, Nestle, says it has made a scientific breakthrough that can sharply cut the sugar in its chocolate.
The company, which makes Kitkat and Aero, says its researchers have found a way to structure sugar differently, so that it uses 40% less.
It claims this can be done without affecting the taste.
Nestle says it is patenting the findings, and it would start using the new sugar across its range from 2018.
Its scientists altered the structure of sugar so that it dissolves more quickly.
This fools the taste buds, with the effect of raising the sweetness, claims Nestle.
The company's chief technology officer, Stefan Catsicas, described the work as "truly groundbreaking research".
It is hard to generalise about how much sugar is in chocolate, as it varies from brand to brand.
But milk chocolate is typically 50% sugar - some of which comes from the milk used.
White chocolate could be as much as 60% sugar.
The amount of sugar in dark chocolate is highly variable. It can be as much as 40%, but it can have no sugar in it at all, although most people would consider that much too bitter.
Professor Julian Cooper, chair of the Scientific Committee at the Institute of Food Science and Technology, said Nestle's development was important: "This is good science. A lot of people have been looking at sugar trying to reduce the amount."
He said this would give Nestle products that use the adapted sugar the "halo-effect", in that people may think they can eat more.
But Professor Cooper, who has worked in sugar for 40 years, said Nestle's patents could spur rivals to make similar advances: "A patent is a double-edged sword. Although it protects what you have done it also tells your rivals about it."
Nestle has been cutting sugar across its range of products since 2007 when it introduced a "global policy on sugar reduction".
Other food companies have made technological breakthroughs with ingredients. Six years ago, PepsiCo, which owns the Walkers crisp brand, developed a designer salt molecule that it said would allow it to use less sodium without affecting taste.