The celebrity chef Hugh Fearnley-Whittingstall is joining forces with Labour’s deputy leader, Tom Watson, to ask people to stop drinking fizzy drinks for a month.

Their backing of the Fizz Free February campaign coincides with the release of figures that show a 70% rise in the number of teenagers with diabetes in the space of four years.

The campaign is targeted particularly at young adults and children and aims to break the habitual consumption of drinks with added sugar, which can lead to obesity and tooth decay.

Other public figures to have signed up include the health secretary, Matt Hancock, and his Labour shadow, Jonathan Ashworth.

For Watson, who managed to reverse his own type 2 diabetes with a rigorous, sugar-free diet and exercise regime, the campaign is not just about saving younger people from health problems but also about fighting back against corporations that profit from children’s high sugar consumption.

“The heaps of sugar companies are putting in their fizzy drinks are as good as poisoning our kids,” he said. “With scores of children suffering from tooth decay, obesity and even diabetes, we must do something to alert people to the danger of too much sugar,” he said.

Sugary soft drinks, mainly fizzy drinks, make up an average of 22% of the sugar intake for 11- to 18-year-olds, the single largest source of sugar in their diets.

Figures obtained by Watson’s office via a parliamentary question show that 605 people aged under 20 were diagnosed with a form of diabetes in 2013. In 2017 the figure was 1,030, according to the Department of Health.

As well as causing obesity and type 2 diabetes, excess sugar consumption is linked to tooth decay. It is estimated that every 10 minutes a child in the UK has a tooth removed because of preventable tooth decay, and 23% of all five-year-olds in England have at least one decayed, missing or filled tooth.

The Fizz Free February initiative, first launched last year by Southwark council, is part of a wider campaign to tackle the obesity crisis. Nearly two-thirds of adults in England are either overweight or obese and 34% of children leaving primary school are overweight or obese.

Fearnley-Whittingstall, who lost 9lbs last year by cutting out sugary snacks, said: “Evidence for the damaging effects of sugar is mounting up. We’ve got to find ways to drastically reduce our consumption of sugar, and Fizz Free February is a fantastic way to start.”

Public Health England’s dietary advice states that adults should consume no more than 30g of sugar per day, while children aged seven to 10 should have no more than 24g and children aged four to six no more than 19g.

Despite the introduction of the sugar tax last April, many fizzy drinks still contain very high levels of sugar. A can of Coca-Cola Classic contains 35g of sugar, which is 145% of a child’s recommended daily sugar intake.

A spokesman for the British Soft Drinks Association said the industry “recognises it has a role to play” in tackling obesity, particularly among children.

“Soft drinks is the only category to have already hit Public Health England’s calorie-reduction target of 20% by 2020,” he said.

• This article was amended on 26 January 2019 to clarify that excess sugar consumption is linked to type 2 diabetes, not other forms of the condition. It was further amended on 29 January 2019 to remove a reference to Irn-Bru, a can of which now contains 16g of sugar, not 34g as stated.