In the early days of the pandemic obesity was identified as a key factor behind hospitalisation rates and deaths from Covid. The Prime Minister knew this personally, from his own brush with mortality last April.
This is on top of the already well-established links between obesity and other life-threatening conditions such as Type 2 diabetes, cancer and heart disease.
The government’s strategy to combat obesity, published at the end of July last year, is full of earnest intentions.
Weight management services by the NHS will be expanded, with evidence-based tools and apps being made available. Calorie labels are being added to food and drink in more and more situations.
Yet the sheer scale of the problem is not really grasped. It is not just the numbers. Nearly 30 per cent of all adults are obese and some 33 per cent of school children.
The phenomenon is without precedent in human history.
Indeed, for most of the existence of humanity, most people lived close to starvation levels. Only the very rich could ever get fat.
Historically, and even today in poor countries, there is a strong positive correlation between obesity and income.
In the last three decades, this has been dramatically reversed. It is the poor who are fat.
In America, for example, in 1990, Mississippi had the highest obesity rate of any state, at 15 per cent of the population.
The inhabitants of any such state now would look exceptionally svelte. The lowest obesity rate is in Colorado, at 24 per cent of the population. In no fewer than 12 states, more than 35 per cent of all adults are obese, and all of them are poor by American standards.
Simply providing more information about the dangers of being obese is unlikely to prove very effective.
A fundamental challenge to reducing obesity arises from what economists call hyperbolic discounting. The concept was initially developed by David Laibson of Harvard in the 1990s and has strong empirical support.
The issue is straightforward. You do something you enjoy today, but which has costs in the future. How do you compare future costs to current benefits?
Hyperbolic discounting simply means that you place huge emphasis on the present and the immediate future. You discount any costs beyond this short horizon heavily. It does not mean you are unaware of them. Even if you know, you just do not pay much attention to them.
The same problem arises with climate change policies. Yes, you know the risks. But they are in the future and right now it is cold, so turn up the central heating.
From the decades long campaign against smoking, it seems that promoting the idea that peer groups are giving up can be effective.
Whatever route is chosen, obesity will not be solved by gimmicks such as NHS apps and sugar taxes.
It is a problem without precedent and needs serious scientific study in just the same way that monies have been poured into Covid vaccines.