Will a ban on snacking on public transport really help combat obesity?

https://www.newscientist.com/article/2219631-will-a-ban-on-snacking-on-public-transport-really-help-combat-obesity/

Woman eating sandwich on London underground

Snacking on the London Underground would be banned under a new proposal

Anadolu Agency/Getty Images

Eating and drinking while on urban buses, trams and trains should be banned to help address the rising rate of child obesity, according to a report published today by the outgoing chief medical officer for England, Sally Davies.

It isn’t the only recommendation made in the report. There are 49 in total, including less controversial ones, such as a call for more research on why people in the West are growing fatter, on average.

But the ban on snacking while travelling has attracted the most attention. Although there would be exceptions for drinking water, for breastfeeding and for anyone with a medical need to eat, it would apply to adults as well as children.

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There have been complaints on social media that it would make things harder for those with busy lives who need to refuel while travelling to work, for instance. So what is the supporting evidence?

In the report, the travel snack ban comes as part of a set of strategies aimed at letting children grow up “free from marketing, signals and incentives to consume unhealthy food and drinks”. The other proposals in this group, such as further restrictions on junk food adverts, at least have some clear logic behind how they would achieve this goal, whether or not you agree with them.

But the link between obesity and a habit of eating while travelling is less clear, and Davies doesn’t provide much explanation. Her idea seems to have come out of the blue.

It is fair to say that most people eating while on public transport probably aren’t having a lovingly prepared salad – we are more likely to be scoffing a chocolate bar or a packet of crisps. As Davies points out, sweet and savoury snacks are thought to be a particular contributor to obesity. Portion sizes have been rising on the whole, especially in food eaten outside the home. The average size of a family pack of crisps, for instance, has risen by 50 per cent in the past 20 years, from 100 to 150 grams.

Other studies have shown that children respond to unhealthy food being advertised on television by eating more of it, and fail to compensate by eating less at subsequent meals. “This will, over time, lead to weight gain,” says Davies.

Perhaps the aim of the ban is simply to whittle away at the opportunities we have for cramming in the calories, or maybe it is to stop children seeing the adults around them enjoying these foods. But the report does have the whiff of a move away from gently nudging people into eating less unhealthy food to physically stopping them from doing so.

It would chime with other more combative anti-obesity policies coming into vogue, such as banning snack vending machines in hospitals and restricting the number of takeaway shops allowed to operate in any given area.

We can’t find out more about the evidence to support the travel snack ban, as Davies has recently stepped down from her position as chief medical officer and the relevant government press office says this means it doesn’t have to answer any questions about it.

That isn’t good enough. True, Davies’s recommendations won’t automatically be followed, but the report was commissioned by UK health secretary Matt Hancock earlier this year and has become an official public document that is likely to influence future health policy. The public has the right to know how well supported it is by facts.

The rising rate of obesity has been called, with some justification, the biggest public health problem currently faced by Western countries. Other anti-obesity initiatives have failed before. It is vital that any further steps we take to combat it are firmly grounded in evidence.

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