SOME top-selling brands of flavoured mineral or spring water contain more sugar in a litre than there is in a Mars bar.

Fruit-flavoured waters marketed by Volvic, Waitrose, Marks & Spencer and Danone contain between 48g and 78g of sugar per litre — the equivalent of 10-15 teaspoons. A standard Mars bar contains less than 45g.

The mineral waters — which are colourless, boast of their “natural” properties and are often targeted at children — are rapidly growing in popularity as shoppers shun other “unhealthy” soft drinks such as Coca-Cola.

However, consumers may be unaware of the sugar content as the “nutritional analysis” on the bottle’s packaging often reveals only that the water contains “carbohydrates”. Sugar is a type of carbohydrate.

The worst offender in the Sunday Times study was Waitrose’s Raspberry Ripple spring water — part of the supermarket’s “good food for children” range — which contains 19.5g of sugar in a 250ml bottle, only marginally less than a small glass of Coca-Cola. A child drinking the water, a popular inclusion in school lunchboxes, would consume almost half the government’s recommended maximum daily intake of sugar in one small bottle.

The bestselling flavoured water, Volvic’s Touch of Fruit, contains 55g of sugar per litre.

A senior executive at a rival soft drinks firm, which does not produce the waters, said the sugar content of the products “beggared belief”.

“When you buy Coca-Cola or something similar you know it contains sugar,” he said. “But, with these products, consumers think they are buying a healthy bottle of water with a squeeze of fruit, but they are actually purchasing a highly sweetened and flavoured soft drink disguised as water.”

Other mineral waters exposed by the study include Danone’s Activ for children containing 16g of sugar in a 330ml bottle, more than three teaspoons. The water’s packaging boasts that it is “low” in sugar — in apparent breach of government guidelines.

Marks & Spencer sells an own-brand litre of spring water that is described as having been “subtly blended with natural flavours of lemon and lime”. It contains 49g of sugar.

Last week, the Food Standards Agency (FSA) said the water manufacturers could be prosecuted if local trading standards officials thought the labelling was misleading.

A spokeswoman said: “They may be prosecuted under the Food Labelling Act because it is illegal for labels to be misleading. We are currently looking at the issue of labelling and one option could be for high-sugar drinks to come with a warning.”

A spokesman for the Food Commission, an independent pressure group, was also critical of the waters. “These products usually use images of fruit so it looks like they contain real strawberries or oranges. But describing sugar as carbohydrate is a mischievous way of concealing the truth,” he said.

The government, which has concentrated on reducing salt levels in food over the past few months, is preparing a clampdown on sugar in the new year. Imogen Sharp, head of health improvement at the Department of Health, recently told doctors: “Sugar is next, once the present campaign on salt is over. We will be looking at a campaign to reduce the amount of sugar people are eating.”

The FSA advises people to eat as little sugar as possible as it contains few nutritional benefits. However, it produces energy, or “empty calories”, which, if not burnt up by exercise, are converted into fat.

More than three-quarters of British adults are now considered overweight and 22% are officially obese. Sugar has also been linked to an increase in type 2 diabetes and contributes to heart disease by raising cholesterol levels. It also causes tooth decay. A recent study in the British Dental Journal found that the risk of tooth erosion among 14-year-olds consuming sugary drinks was 220% higher.

Last week, spokesmen in Paris and London for Danone, which owns Volvic, declined to comment on its waters’ sugar content.

Marks & Spencer said: “We offer a range of waters which contain either sugar or artificial sweeteners and provide full nutritional information on our products, which includes the sugar content, so customers can make an informed choice. We constantly review our products and will change the recipe as long as the quality is not compromised.”

Waitrose said: “The Food Explorers Raspberry Ripple spring water drink contains apple extract and sugar to deliver a natural sweetness. The use of artificial sweeteners is not permitted in any Waitrose Food Explorer products.

“To meet our customers’ requirements, we aim wherever possible to offer a choice of drinks containing sugar and drinks containing sweetener. We do constantly review and update our ranges as a result of customer feedback.”

Additional reporting: Sarah Keenlyside

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