The UK government could scrap its entire anti-obesity strategy after ministers ordered an official review of measures designed to deter people from eating junk food, the Guardian can reveal. The review could pave the way for Liz Truss to lift the ban on sugary products being displayed at checkouts as well as “buy one get one free” multi-buy deals in shops. The restrictions on advertising certain products on TV before the 9pm watershed could also be ditched. The review – which was ordered by the Treasury – is seen as part of the prime minister’s drive to cut burdens on business and help consumers through the cost of living crisis. Whitehall sources said the review was “deregulatory in focus” and is expected to lead to the new government jettisoning a raft of anti-obesity policies inherited from Boris Johnson, Truss’s predecessor in Downing Street. The process – which the Department of Health and Social Care referred to as an “internal summary” of the evidence around obesity policy – will also look at possibly ditching calorie counts on menus in many cafes, takeaways and restaurants. These are designed to encourage people to choose healthier dishes and only became mandatory in April. The review is so radical in scope that it may even look at whether the sugar tax, which began in 2018 and has helped make soft drinks much less unhealthy, should go too. Health experts have hailed the levy as a key initiative in the fight against dangerous obesity. “There doesn’t seem to be any appetite from Thérèse [Coffey – the new health secretary] for nanny state stuff,” one source said. Truss also made Coffey her deputy prime minister after taking office last week. Officials at the Office for Health Improvement and Disparities, the part of the Department for Health that formulates policies to tackle major public health problems, were said by a source to be “aghast” at the prospect of Truss potentially discarding strategies to counter junk food that have been agreed and approved by parliament. Almost two-thirds of adults Britons are overweight or obese. Obesity costs the NHS an estimated £6.1bn a year to treat because it is an increasingly common cause of cancer, diabetes, heart conditions, painful joints and other health problems. Johnson decided to make tackling foods high in fat, salt or sugar a personal priority as a result of his own admission to intensive care with Covid-19 in April 2020. A large majority of people who have needed life-saving care after becoming infected during the pandemic had high levels of excess weight, studies have shown. The Obesity Health Alliance, a grouping of 50 health charities and medical organisations, said setting aside the government’s main weapons against obesity would be “a kick in the teeth”. “We are deeply concerned. It would be reckless to waste government and business time and money rowing back on these obesity policies, which are evidence-based and already in law. These policies are popular with the public, who want it to be easier to make healthier choices,” said Katharine Jenner, the alliance’s director. The unpublicised review has also provoked unease in Conservative ranks. James Bethell, a health minister until last year, said such a major U-turn could exacerbate Britain’s obesity problem. He challenged Truss’s apparent rationale for contemplating such an unexpected departure, which is that it would cut red tape faced by business and help promote economic growth – her key priority and the focus of the chancellor Kwasi Kwarteng’s emergency mini-budget, expected next week. “Improving the nation’s health is one of the best ways we can increase productivity and workforce capacity and thereby drive growth. So I would be very surprised by any decisions that actually strive to make the UK less heathy,” the Tory peer said. Truss pledged during the Tory leadership campaign to light a bonfire of obesity rules if she won. “Those taxes are over. Talking about whether or not somebody should buy a two-for-one offer? No. There is definitely enough of that,” she told the Daily Mail last month. “What people want the government to be doing is delivering good roads, good rail services, making sure there’s broadband, making sure there’s mobile phone coverage, cutting the NHS waiting lists, helping people get a GP appointment. They don’t want the government telling them what to eat”, she added. A leading health campaigner, who did not want to be named, said Truss’s readiness to abandon the approach to obesity was “ideological” and driven by her belief in minimal regulation of business. Johnson legislated to ban junk food ads on TV before 9pm and online, multibuy deals, and sweet treats at checkouts, aisle ends and entrances in supermarkets. The measures were due to affect a wide range of foods such as snacks, breakfast cereals, pizzas, cakes, confectionery and desserts. However, in May he delayed until 2023 and 2024 the introduction of all but the last measure, which is due to take effect on 1 October, subject to the review, citing soaring inflation and the pressure on families’ budgets as the reason. That move led Jamie Oliver to stage a protest at Downing Street. The celebrity chef said: “To use cost of living as an excuse is wrong. It [action on obesity] is absolutely urgent and the excuses that he’s used for not doing it are absolutely not true.” The Department of Health has been approached for comment. • This article was amended on 13 September 2022. An earlier version incorrectly said the review had been commissioned by the health secretary, Thérèse Coffey. It was the Treasury that ordered it. And the Department of Health and Social Care describes the process as an “internal summary”, rather than a formal review; this has been included.