Dozens of health and children’s groups have urged ministers to tackle obesity by imposing taxes on foods containing too much salt or sugar.

New levies based on the sugar tax on soft drinks would make it easier for consumers to eat more healthily by forcing food manufacturers to reformulate their products, they claim.

Their plea comes in a letter from 35 groups to the chancellor, Rachel Reeves, and the health secretary, Wes Streeting. The signatories include groups representing the UK’s doctors, dentists and public health directors, health charities including Diabetes UK and the World Cancer Research Fund, and a senior figure in the chef Jamie Oliver’s organisation.

The health groups believe taxing unhealthy foods such as cakes, sweets, biscuits, crisps and savoury snacks would generate billions of pounds for the Treasury and cut the number of people becoming ill as a result of a bad diet.

Polling shows two-thirds of the UK public support taxes on such products as long as the revenue is ploughed into children’s health.

The representative survey of 4,943 British adults by YouGov, commissioned by food campaigners’ Recipe for Change initiative, also found that:

• 74% think food firms are not honest about the health impact of their products.

• 61% worry about the amount of sugar and saturated fat in what they eat.

• Only 13% believe producers will make their food more nutritious without government intervention.

• 72% worry about high levels of processing used in food production.

Reeves announced in the budget last week that the Treasury was looking into whether the sugar tax, which came into effect in 2018, should be extended to other very sweet products, including milkshakes and highly sugared coffees. It is widely regarded as having been a success.

Anna Taylor, the executive of the Food Foundation, which also signed the letter, said: “The damage the food industry is doing to children’s health is the biggest threat to our nation’s wellbeing and future productivity and this needs to be reined in – urgently.

“The government must now get bolder, creating real incentives to force the industry to align with public health goals, further and faster.”

The government-commissioned National Food Strategy published in 2021, drawn up by Henry Dimbleby, a co-founder of the Leon restaurant chain, first proposed the idea of a new “salt and sugar reformulation tax”.

In recent months the House of Lords’ food, diet and obesity committee, the Institute for Public Policy Research (IPPR) and the British Heart Foundation have expressed support for food taxes.

The health groups want ministers to start tightly regulating the food industry. They said relying on the industry to voluntarily clean up its act nutritionally, as the previous Conservative governments did during 2010-24, had not yielded meaningful change.

“Voluntary reformulation programmes for sugar, salt and calories are not proving effective enough, achieving only a 3.5% reduction in sugar levels of key product categories, compared to the mandatory soft drinks industry levy (sugar tax), which has achieved a reduction in total sales of 34.4% between 2015 and 2020,” the letter says.

Only 34% of the world’s 30 biggest food and drink firms’ sales globally are from more nutritious “healthier” products, according to a report published on Thursday.

While 70% of Danone’s, 65% of Barilla’s and 58% of Arla’s sales come from such products, only 38% of Coca-Cola’s do, with even lower proportions for Kraft Heinz (35%), Nestlé (33%) and Mars (15%).

Producers generally are making little progress in improving the nutritional quality of their output, despite pressure from health groups and governments to reformulate, according to findings collated by the Netherlands-based nonprofit the Access to Nutrition Initiative.

Jamie O’Halloran, a senior research fellow at the IPPR, said: “Without bold regulatory changes, our food system will continue to fall short in promoting healthy lifestyles, particularly for those on the lowest incomes.

“Expanding levies to cover other high-sugar and ultra-processed products could be transformative, especially if the resulting revenue is used to support low-income households to make healthy food choices.”

Manufacturers were already making their products healthier, the Food and Drink Federation said. “Companies have made significant progress to create healthier options for shoppers. As a result, our members’ products now contribute 25% less sugar, 24% fewer calories and 33% less salt to the British grocery market compared to in 2015, and have also delivered 190m additional servings of fibre to the population,” a spokesperson said.

A government spokesperson said: “Obesity is a significant health challenge, which affects 26% of adults and costs the NHS £11.8bn per year.

“The budget took action to ensure the soft drinks industry levy maintains its incentive to encourage healthier soft drinks, and we will publish a 10-year health plan in spring 2025.”