Dr Stuart Flint, of Leeds Beckett University, said the benefits of the policy cannot be underestimated after it came into force in the capital on February 25.
It means buses, trains and tube services run by Transport for London are prohibited from displaying posters and adverts promoting food and drink high in fat, sugar and salt. The ban also applies to roundabouts, bus stops, taxis and trams.
Dr Flint said: “I cannot overstate the potential benefits of this policy. Children from a very young age are exposed via public transport and other forms of advertisements to the promotion unhealthy food and drinks.
“There is no doubt that this influences favourable attitudes among young people to these products, and they are much more likely to consume them as a result.”
Almost one in four children finishing primary school in Leeds are classified as obese.
Statistics from Public Health England show that 19 per cent of year six pupils were declared obese between April 2016 and March 2017, and four per cent severely obese. Some 14.4 per cent of year six children were declared overweight and on average, 38 per cent of youngsters are unhealthily overweight when they start secondary school. Dr Flint, who has contributed to the All-Party Parliamentary Group on Obesity, said the advertising ban would also help tackle type 2 diabetes and poor dental health.
He said: “Public transport companies should take more responsibility to support the health of our population or at the very least not encourage unhealthy behaviours.
“This policy is needed across the UK, not just in London. Local authorities should be considering this policy and the potential impact that it could on child and adult health nationally.
“Junk food companies are well aware of the impact of advertising their products on and around transport. They have a captive market on the transport network, and this daily, constant exposure has a great impact on consumer attitudes and behaviour. These adverts work on a continuous and subconscious level.”
More than 40 per cent of young people in the UK aged five-19 are classed as overweight or obese. Almost 43,000 children in England had operations to remove rotten teeth in 2017, at a cost of about £36m to the NHS.
Dr Flint added: “Banning these adverts nationwide will have enormous benefits, not just in relation to the high prevalence of overweight and obesity, but also in areas such as diabetes and poor dental health.”