Food manufacturers have been told to cut sugar by 20 per cent by 2020Credit:Alamy “We will publish details of exactly who is doing what and in the event which we don’t see progress we will be giving further advice to the Government.“We can’t duck the fact a third of children are leaving primary school overweight or obese and obesity generally is having a profound effect, not just on the costs offer the health service, but on the overall health of the nation. This is the most ambitious childhood obesity plan in the world.” “However, the missing factor in this report is how these targets will be enforced. We’ve seen over recent weeks that some companies within the food and drink industry have made great progress whilst others are seriously lagging behind and others claiming wrongly that they can’t do it.”However, Duncan Selbie, the Chief Executive of PHE, said companies who failed to meet the targets would be named and shamed, and argued that implementing legislation would leave the Government open to years of protracted argument in the courts.“We didn’t want to spend years in judicial review arguing about whether a jaffa cake is a cake of a biscuit,” he said. Show more But the new guidance states that companies who do not want to reformulate can meet targets by simply cutting the size of their products. PHE said chocolate companies may find reformulation ‘difficult’ and that reducing size was probably the most sensible solution.However, anti-obesity campaigners warned that without reformulation shoppers would encourage shoppers to buy two smaller bars.Tam Fry, of the National Obesity Forum, said: “Simply down-sizing sugary food is not the answer. Of the four options given to industry to remove 20 per cent sugar from their products, down-sizing runs the real risk that people will buy two of whatever the product is and eat substantially more.“The preferred option is to reformulate the entire product and replace sugar with other ingredients.”Although other experts praised the sugar reduction targets, they questioned whether manufacturers would actually meet the voluntary commitment if there were no sanctions for failing to comply. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Chocolate bars are likely to shrink by a fifth in the next three years after Public Health England told sweet manufacturers they could meet obesity targets by cutting product size.Today PHE published new guidelines which call on food manufacturers to reduce the sugar content of cereals, breakfast goods, yoghurts, biscuits, ice creams, sweet spreads and confectionery by 20 per cent by 2020.The cuts are intended to reduce the number of children who are overweight or obese by the end of the decade and take 200,000 tons of sugar out of the British diet each year. A record percentage of children now have weight problems with one in three overweight or obese, by the time they leave primary school at the age of 10 or 11. Studies have shown that being overweight in childhood makes future health problems, such as Type 2 diabetes, far more likely and places a huge burden on the NHS. Under the Government’s plan, from 2018 a sugar tax will be imposed on drinks which have more than 5g of sugar per 100m, which would add around 7p to can of Coca-cola. Graham MacGregor, professor of Cardiovascular Medicine at Queen Mary University of London and chairman of Action on Sugar, said: “We congratulate PHE’s tremendous achievement on setting coherent and achievable sugar reduction targets in such a short space of time.