CUTTING the amount of sugar in sweetened drinks by 40 per cent could prevent 300,000 cases of Type 2 diabetes and one million cases of obesity, research suggests.

The study, published in The Lancet Diabetes and Endocrinology journal, states that this reduction in sugar-sweetened beverages (SSBs) - including fruit juices - over five years could also lead to 500,000 fewer cases of people being overweight over two decades.

Some fizzy drinks contain around 10 teaspoons of added sugar.

The Lancet study was led by Professor Graham MacGregor, chairman of the Action on Sugar group, who said its action plan needed to be backed up by a Government-funded but independent nutrition agency "which can set mandatory targets with robust enforcement".

He added: "In support of this, the British Retail Consortium is now calling for regulated sugar, fat and salt reduction targets.

"The UK food and drink industry could lead the world in preventing obesity and type 2 diabetes."

It comes after Shirley Spear, founder of the Three Chimneys restaurant on Skye who is now chairing the Scottish Food Commission, dismissed calls for a sugar tax and said there needed to be changes at "production level, whereby we target the manufacturers rather than the public".

In the new study, researchers used data to calculate the level of SSB consumption and its contribution to energy intake in the UK population.

They then estimated how the reduction would affect body weight per person, and overall results for the adult population.

These calculations showed that a 40 per cent reduction in sugars added to SSBs over five years - provided they are not replaced by artificial sweeteners - would lead to an average reduction in energy intake of 38.4 calories per day by the end of the fifth year, in turn leading to an average 2.6 pounds reduction in adult body weight.

This in turn would prevent more than a million cases of disease.

The predicted impact was found to be greater in adolescents, young adults and individuals from low-income families who consume more SSBs, the research said.

But researchers said that the gradual sugar content reduction would not affect sales or product prices.

Professor Stephen O'Rahilly, from the University of Cambridge, said: "This is a purely theoretical study and there are many assumptions made which reduce confidence in the statements regarding the precise extent of the health benefit."

He added that, while the evidence surrounding the health dangers of sugar are "hard to argue with", the same does not necessarily apply for replacement sweeteners.

He said: "The best quality evidence currently available indicates that artificial sweeteners do not significantly contribute to human obesity or diabetes.

"It might also be easier to incentivise companies to change the emphasis of their manufacturing and marketing toward versions of their current products that contain non-caloric sweeteners rather than to unsweetened drinks such as bottled water."

Tam Fry, from the National Obesity Forum, said: "It is paramount that everyone in the UK strives to reduce their sugar consumption by half. That's easier said than done but the 40 per cent reformulation proposed by Action on Sugar would make a significant start.

"As the paper states, people will need time to adjust their taste buds to accept a lower sugar hit and the forum has reservations that such a dramatic cut could be achieved by 2022."