After Christmas, like everyone else, the residents of Wolverhampton will be going on a diet. But they will have the added incentive of being bribed by the state. As part of a new anti-obesity scheme, they will be offered fitness trackers that monitor their physical activity, and an app that registers their shopping habits and calorific intake. By increasing their daily step count and improving their diet, they will be able to earn points which can then be spent in shops and cinemas.

Will it work? Of course not. They may shed a few pounds in the short term, but it will all go back on. Common sense – along with empirical evidence – tells us that bribes are a terrible way to motivate long-term change. A 2015 Cambridge University review of 34 such incentive schemes found they had no sustained effects on diet or exercise.

To be fair, it’s not just bribery that doesn’t work. Since 1992, UK governments have tried 689 different obesity policies – and still we keep getting fatter. Almost one in three people over 45 in England is now clinically obese: a condition that makes you 1.5 times more likely to die from Covid, not to mention the traditional ailments that come from carrying too much flesh. 

A problem of this scale is clearly systemic. Yet the Government – like most people, including those who are clinically obese – still believes that individual willpower is the issue. If only the state could find a way to strengthen our resolve, through public health campaigns, education or bribes, we might heave our enormous bottoms off the sofa and start taking better care of ourselves.

But why has willpower only become an issue in the past 70 years? In 1950, the average Briton had a BMI of 20 – slightly underweight – not because of some generational surfeit of self-control, but because there simply wasn’t so much to eat. The food on offer was sparser, less processed, more expensive and much less calorific.

Our evolutionary appetites have not changed for thousands of years: we instinctively crave fatty, sugary foods, because these are rare and precious in the wild. It’s only now – since the agricultural and manufacturing revolutions of the 1960s made it possible to produce cheap, high-calorie food in abundance – that these appetites have become a threat to our collective health.

If the Government ever wants to get serious about tackling obesity, it will have to start by introducing financial incentives and constraints for manufacturers and retailers. They create the food landscape; consumers just live in it. Bribing individuals to eat healthily is pitifully unrealistic: like handing us each a teaspoon with which to dig our way out of an avalanche.

‘Tis the season to be sustainable 

The discovery of the oldest working iron in Britain – a Morphy Richards bought in the early 1940s for 41 shillings, and still going strong – has given me an idea. Might it be possible, this Christmas, to only give presents that will last forever?

There are hipster websites, in the further reaches of the web, selling robust tweed overcoats and cast iron skillets handcrafted by Norwegian dwarves. They cost a bomb, and they’re not much good for children. But the greatest gift of all – so I will assure my crestfallen brood, as they unwrap their sustainable hessian socks – is the future of the planet.