"For centuries chocolate has been an energy-boosting, mood-enhancing indulgence, but at last the Holy Grail is in sight: a healthier version that reduces the guilt of indulgence.

Scientists from Scotland's Rural College (SRUC) are helping to perfect a range of luxury chocolates that not only has the normal taste and texture but jettisons fattening refined sugars as a main ingredient. They have teamed up with chocolatiers to use natural sugars from plants to capitalise on rising demand for healthier varieties.

Chocolate has been popular since it was first brought to the UK in the 17th century. The average citizen eats more than 6.5 kilograms a year, wolfed down usually in the knowledge that it adds to the waistline. Over-consumption of refined sugars has been linked to obesity, type 2 diabetes and heart disease.

Alistair Trail, senior consultant at SRUC's scientific advisory arm, said: "Healthy chocolate is a growth market. The challenge with chocolate is altering the ingredients without losing the familiarity of the flavour or texture associated with it."

SRUC scientists have experimented with natural sugars from fruits to replace the refined sugars from beet that can give an instantaneous energy high, followed by a slump. The effect of the whole food plant sugars is not as intense but lasts for longer. They also contain more nutrients.

Mark Barker, the SRUC development chef involved in the project, said: " If we can have chocolate that is healthier while delivering the same taste and texture then it has to be win-win. It has been about trial and error and constant experimentation."

Sue Lawrence, the food writer and Masterchef winner, believes consumers would welcome healthier chocolate. "There are lots of unrefined sugar alternatives that could be used," she said. "They contain far more in terms of nutrients. The difficulty when talking about chocolate comes in recreating that lovely, melt in the mouth texture."

Susie Greig, who runs the wellness company Revive in 10 in Troon, Ayrshire, has collaborated with the SRUC team on creating sweetness and milky texture. "It is a matter of looking at the essential ingredients and seeing what you can change to make it healthier," she said. "We want to offer people the choice of a nutritious chocolate product with no reason to feel guilt,"

The company's new range includes peppermint and orange-flavoured dark and milk chocolate. "People say they love it," Ms Greig said. "It's nice and soft and melts in the mouth. You don't get the same instant high and craving to eat more but that's the point."