Britons Aren’t That Fat

The UK is one of the world’s fattest nations. But Britain isn’t actually all that overweight.

To understand how both those things are true you have to understand the mathematics of weight.

Fattest Nations

The UK is the fortieth most overweight nation on Earth according to the World Health Organisation. That puts us into the heaviest 20% of countries.

Unfortunately, that is actually a bit flattering to the UK thanks to dozens of tiny places with unique issues and anomaly-prone data like Naru and the Marshall Islands.

For a more useful (but less flattering) context, in all of Europe only Ireland and tiny Andorra are more overweight than the UK. In fact, the USA is the only large Western Democracy heavier than Britain. So we appear to have a big big problem.

Yet we actually really don’t.

Big Nations are Tiny Margins

The typical body mass index of a UK adult is 27.3 – slap bang in the middle of the “overweight” range.

Yet if that dropped by just 2 points – or 7% – the UK wouldn’t even be in the heaviest 100 countries. We’d be as healthy as famously active nations like Sweden and Holland.

That seven percent is akin to a typical Brit losing less than one stone in weight.

Typical Britons are Small

The average man in Britain is roughly 5ft 9in tall. The average woman is 5ft 3in tall. The average UK Body Mass Index is 27.3. This all means the average Briton is either a man who weighs 13 stone and 3lbs, or a woman who weighs eleven stone exactly.

Crucially, that means the average UK woman is less than one stone overweight. That is because the healthy weight range goes up to 10st 1lb for a woman of 5ft 3in. The average man is also just one stone and two pounds overweight (his healthy range goes up to 12st 1lb for his height).

Overweight is a Narrow Band

For what is a comparatively fat country, it seems surprising to find that the UK adult population has a large number of people who are overweight by such small amounts – and thus a lot of people who are not much heavier than their healthy weight. But that’s the maths behind national weight.


What this means is that over a third of adults are in a very narrow band labelled “overweight” but not obese. That’s more than 17million adults clustered around (roughly) one stone overweight. Indeed, the incremental nature of the split even means that many millions in the “obese” category are only three, four or five stone above their healthy weight too.

This matters because when statisticians and Prime Minister’s talk about the “overweight and obese” as a major national problem, it sounds like a lot more than a little excess weight – and so it makes mountains out of our molehill bellies. This is very demotivating and leads to the wrong personal and national approaches to weight.

And there’s more misconception to overcome too.

Weight is a Trend, Not an Outcome

When we think of weight, we think of a fixed number. I was weighed by the NHS part way through writing this article, so I know my weight in kilos right now. But the NHS doesn’t care about my weight as a static number. It weighs me because weight change between appointments might matter.

This is critical to really understanding how small the UK weight problem is. Very few people get fat quickly as a result of a trigger event. Even me, developing a severe chronic illness (a natural trigger event), took two years to go from a healthy weight to the lightest edge of obese.

More importantly, the data is clear that UK weight-gain is gradually cumulative with age, meaning it happens due to tiny daily imbalances in lifestyle over many years. This is why our weight as a nation goes from mostly healthy among young adults, to increasingly overweight+obese as we get older. 

Or to put it a more useful way, even my relatively rapid rise in weight due to chronic illness was actually only a weight-gain of a lb a fortnight, and most overweight adults have experienced a much slower rise in weight than that.


Such a widespread and long term gradual weightgain in the UK is clearly a structural problem with how our country operates, not just a lot of individual personal anomalies.

But it is only a small structural misalignment.

Take those 17million people I mentioned before, all clustered around 1 stone over weight. We have gained that excess 1 stone (give or take) very gradually over many years (in most of our cases). So our misalignment of lifestyle on a daily or even yearly basis is actually really tiny.

Gradualism in Calories

One stone overweight is effectively 50,000 calories overweight because 1 stone of weight gain typically means eating 50,000 more calories than burned. Likewise, losing one stone means burning 50,000 calories more than we eat.

So millions of typical Britons have consumed an excess 50,000 calories over years and years. And 50,000 calories is tiny.

For context, a normal Briton breathing in and out and leading a normal but somewhat inactive life, burns in the region of 750,000 calories a year. So putting on a stone (50,000 calories) in as short a time as one year, or losing it, involves the tiny matter of less than 7% imbalance between what we eat and what we burn.

Put another way, 137 calories a day might be all that it takes to lose a stone in weight every year, or gain it. That’s only about one glass of Pepsi, or a slice of toast with margarine, or a 20 minute walk. And since we gained our excess weight over many years, our imbalance is usually even less than 137 calories per day.

In other words, while the UK collective bulge seems big, our bulges divided up among us are not. As such, the changes needed to flatten them are mostly tiny so long as we don’t imagine innapropriate timescales. We get fat over years, so it is reasonable to lose weight over years.

Can we Afford Gradual Change?

The best thing about all of this is that almost all of us have time on our side.

Very few of us are facing imminent death if we don’t get our weight down. Being overweight or obese does result in a shorter life and greater ill-health, but not quickly. Type 2 Diabetes, for example, takes years to manifest and shortens life only by five or six years, not twenty. So if you develop it at 40, the expected years lost to you don’t strike for another 30 years.

That’s a lot of time to gradually shed a stone or two in management of a chronic condition – which, as discussed, is enough to put most people back into the healthy weight bracket.

Since we should be seeking sustainable change across a society, this makes it sensible to benefit from the gradualism that got us here, rather than attempt radical sudden impact.

Government Gradualism

In terms of government policy, gradualism manifests in things like the sugar tax or banning all junk food advertising . Even making buses cheaper to get us walking to bus stops instead of driving door to door, might be enough to tip the scales from gradual small weight-gain to gradual small weightloss. It is notable that London, where public transport is heavily subsidised, has the lowest weight problem of any region  (though other factors are apparent too).

Meanwhile, promoting strenuous stuff like the PM going running might be counter-productive. It makes tackling our weight seem very unpleasant and time-consuming. Indeed, because of disability, old age, busy lives or ill-health, things like running appear to exclude millions of us from the weightloss agenda anyway.

Personal Gradualism

When we realise how small an incremental change is involved in switching from gradual weight-gain to gradual weightloss, the choices we are faced with become less frightening.

We don’t have to quit drinking or stop eating biscuits or try to run a mini marathon. Instead, we can do small things like walking to (or even part of the way to) the local shop, hairdresser or station – rather than driving.

We could even (say it quietly) decide there’s better things to worry about than shedding weight if we don’t mind the little the excess we are carrying.

What About the Exceptions?

Gradualism is great for the adults who are not all that overweight after all, and who got there through gradual imbalance. That is the vast majority of us but there are exceptions.

The very heavy: A small proportion of Britons are much larger than most of us. For these people the need for weight loss is greater because the health implications are more severe and more imminent. They also tend to have suffered faster weight gain than most of us (hence they are much bigger people). As such they need very different help to the gradualism most of us can benefit from.

Children: Similarly, child obesity is a whole different subject too. British children are much less likely to be obese or overweight than adults. As such it is not likely young children gained weight as part of a near ubiquitous structural imbalance.  This means these children likely have very different needs in relation to weight than most adults.

Trigger events: These are another exception to the rule. As previously mentioned, the onset of chronic illness can radically change lifestyle by necessity. This can result in relatively rapid weight-gain. That is by no means the only or most common trigger event. Obesity in women notably rises in the age range where menopause is most common, and falls back again afterwards. Such trigger events can be managed and lead to only temporary weight gain, but that is a different function.

The elderly: And finally the very elderly are a unique exception. Having mostly gained weight the same way we all did, the proportion of overweight and obese starts to fall with old age. Sadly, this likely reflects the health implications in old age – at least in part. Not as many overweight or obese people survive long into old age as healthy weight people. That said, action to help older overweight people can’t really rely on Gradualism for precisely that reason. Old age is when many of the worst effects of being overweight hit our health.

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