ONE of Scotland's leading nutrition scientists has branded tough new sugar targets "completely foolish".

Professor Mike Lean, chair of Human Nutrition at Glasgow University's School of Medicine, said a new public health target to obtain no more than five per cent of daily calories from so-called free sugars was misguided and unrealistic when the existing 10 per cent target was far from being achieved.

He said: "It's a completely unrealistic target and therefore completely foolish.

"There's no medical evidence that reducing sugar consumption below 10 per cent to five per cent carries any additional health benefit - absolutely no evidence at all.

"The current average consumption of sugar is around 12-13 per cent. Getting to 10 per cent is a reasonable target and I think we should put some real effort behind achieving that first, but to come up with a new target that is miles away from what is achievable is entirely foolish - no population in the world can do that.

"Even vegetarians from India consume eight per cent of their calories from sugar and they have less heart disease and less diabetes than anyone in the world."

He blamed the Government's reluctance to "flex its muscles" against the food industry for the failure to achieve the 10 per cent target.

The UK's Scientific Advisory Committee on Nutrition (SACN) said the lower limit, in line with World Health Organisation guidance, would help the fight against obesity, diabetes and tooth decay.

It is equivalent to around seven teaspoonfuls of sugar a day for anyone aged 11 or over, roughly the amount in a single can of Coca Cola or Irn Bru.

Free sugars refer to those added to products such as fizzy drinks, fruit juices, pasta sauces, soups, bread, and breakfast cereals, but which also naturally occur in honey and unsweetened fruit juices.

It does not include the fructose found in fruit and vegetables, which are also packed with fibre, or lactose in calcium-rich dairy products such as milk, cheese and natural, unsweetened yoghurts. Starchy carbohydrates, such as pasta, potatoes or wholegrain bread, which break down into sugars, are also exempt.

Nutrition policy is devolved but Scottish Government, like the UK Government, says it will apply the five per cent guideline following advice from Food Standards Scotland.

Recent studies have shown that an average child in Scotland aged three to 16 gets more than 17 per cent of their daily calorie intake from free sugars.

However, Prof Lean said tackling obesity was more complicated than simply demonising sugar. He added that studies had shown people who consume large quantities of artificially-sweetened diet drinks are also more prone to being overweight.

He said: "It's the whole pattern of eating and drinking that's the problem. When people get fat, it's not the sugar that makes them fat - it's the calories, from all sources.

"The people who are getting fat do drink more sugary drinks, but they also drink more diet drinks, they eat a lot more crisps, more high-calories meals, more snacks, more fat."

The Department of Health is also exploring the value of other public health interventions, such as re-formulating products and marketing campaigns.

Professor Ian Macdonald, of the SACN, said: "The evidence is stark - too much sugar is harmful to health and we all need to cut back.

"The clear and consistent link between a high-sugar diet and conditions like obesity and type 2 diabetes is the wake-up call we need to rethink our diet.

"Cut down on sugars, increase fibre and we'll all have a better chance of living longer, healthier lives."

Maureen Watt, Minister for Public Health, said: “There is already a lot of action to improve diet, and we are spending over £10m on projects to encourage healthy eating - including community food initiatives in deprived areas, and the Healthyliving Award on the high street.”