By David Shaw

The last report of the outgoing UK Chief Medical Officer, Dr Sally Davies, is entitled “Time to Solve Childhood Obesity”. It makes many sensible public health recommendations, including increases in the levy on sweet drinks and taxation on snacks, and reducing portion sizes and marketing aimed at children. But a different recommendation grabbed all the headlines: Sally Davies also recommends that the Department for Transport should “Prohibit eating and drinking on urban public transport, except fresh water, breastfeeding and for medical conditions.”

It is all too easy to label this proposal to ban all food and drink on buses and trains – not just snacks and fizzy drinks – as the nanny state in action. This is particularly unfortunate given that this label will also be attached to all the other recommendations, which are much more moderate. But this particular proposal does suffer from many practical and ethical problems.

First, no evidence is provided to back up the recommendation. The issue of snacking on public transport is not mentioned in the report itself, but only in the appended list of recommendations. However, it is justified under Principle 2:  “Allow children to grow up free from marketing, signals and incentives to consume unhealthy food and drinks.” But preventing children and adults from eating and drinking on public transport does not remove marketing or incentives, and seeing other people eat on the bus hardly qualifies as a signal, particularly if it’s only a banana.

Second, given the lack of evidence it seems unlikely that the proposal will have the intended effect. Even if the ban is enforced (by whom?), if children will simply wolf down their food before or after using public transport – which is potentially less healthy than eating it slowly. The ban could also make more children get their parents to drive them to school – ironic when another aim of the report is to is get “More people to switch from driving to public transport, cycling and walking – especially on the school run” (annex G). And of course, if they can no longer eat or drink on the train or bus, many adult commuters will return to using their cars, with detrimental public health effects.

Third, the recommendation is disproportionate; why should everyone have to stop eating on trains and buses in the hope it will stop children snacking? The ban covers not only snacks but also healthy food, inconveniencing commuters whether they have healthy or unhealthy diets. And if the other proposals in the report are implemented, children will no longer have such easy access to large portions of unhealthy snacks, meaning that the ban would become even more disproportionate.

Defending this recommendation on BBC radio, Dame Davies said that “Our prime minister banned alcohol on local transport when he became the Mayor of London.” (from 1:36:20) But the ban on alcohol was narrow, specific, and proportionate; it aimed at reducing violence and anti-social behaviour. It is hardly comparable to banning all food and drink on public transport; apart from anything else, people need to eat and drink, but they don’t need to drink alcohol. Pressed for the thinking behind her proposal, she said “I think we should look at banning snacks because children eat three or more snacks a day – that’s seven cubes of sugar a day – and we have to set an environment where they don’t do that.” But once again, there is no evidence that prohibiting the consumption of all food and drink on urban transport will reduce snacking, even though it would stop adults and children from eating even healthy foods on trains and buses.

As in the case where she said that women should think about the risk of breast cancer before having a glass of wine,  the outgoing CMO has undermined the evidence-based public health measures suggested elsewhere in her report by including among them a measure which is illogical, unethical and misguided.

Author: David Shaw

Affiliation: Care and Public Health Research Institute, Maastricht University and Institute for Biomedical Ethics, University of Basel.

Competing interests: The author sometimes snacks on public transport.