No this really is not “the healthy one”

Today’s Guardian has a column by George Monbiot discussing the issue of obesity in modern England, that I think fundamentally misunderstands the causes of obesity and paints a dangerously rosy picture of Britain’s dietary situation. The column was spurred by a picture of a Brighton Beach in 1976, in which everyone was thin, and a subsequent debate on social media about the causes of the changes in British rates of overweight and obesity in the succeeding half a decade. Monbiot’s column dismisses the possibility that the growth in obesity could be caused by an increase in the amount we eat, by a reduction in the amount of physical activity, or by a change in rates of manual labour. He seems to finish the column by suggesting it is all the food industry’s fault, but having dismissed the idea that the food industry has convinced us to eat more, he is left with the idea that the real cause of obesity is changes in the patterns of what we eat – from complex carbohydrates and proteins to sugar. This is a bugbear of certain anti-obesity campaigners, and it’s wrong, as is the idea that obesity is all about willpower, which Monbiot also attacks. The problem here though is that Monbiot misunderstands the statistics badly, and as a result dismisses the obvious possibility that British people eat too much. He commits two mistakes in his article: first he misunderstands the statistics on British food consumption, and secondly he misunderstands the difference between a rate and a budget, which is ironic given he understands these things perfectly well when he comments on global warming. Let’s consider each of these issues in turn.

Misreading the statistics

Admirably, Monbiot digs up some stats from 1976 and compares them with statistics from 2018, and comments:

So here’s the first big surprise: we ate more in 1976. According to government figures, we currently consume an average of 2,130 kilocalories a day, a figure that appears to include sweets and alcohol. But in 1976, we consumed 2,280 kcal excluding alcohol and sweets, or 2,590 kcal when they’re included. I have found no reason to disbelieve the figures.

This is wrong. Using the 1976 data, Monbiot appears to be referring to Table 20 on page 77, which indicates a yearly average of 2280 kCal. But this is the average per household member, and does not account for whether or not a household member is a child. If we refer to Table 24 on page 87, we find that a single adult in 1976 ate an average of 2670 kCal; similar figures apply for two adult households with no children (2610 kCal). Using the more recent data Monbiot links to, we can see that he got his 2,130 kCal from the file of “Household and Eating Out Nutrient Intakes”. But if we use the file “HC – Household nutrient intakes” and look at 2016/17 for households with one adult and no children, we find 2291 kCal, and about 2400 as recently as 10 years ago. These are large differences when they accrue over years.

This is further compounded by the age issue. When we look at individual intake we need to consider how old the family members are. If an average individual intake is 2590 kCal in 1976 including alcohol and sweets, as Monbiot suggests, we need to rebalance it for adults and children. In a household with three people we have 7700 kCal, which if the child is eating 1500 kCal means that the adults are eating close to 3100 kCal each. That’s too much food for everyone in the house, even using the ridiculously excessive nutrient standards provided by the ONS.  It’s also worth remembering that the age of adults in 1976 was on average much younger than now, and an intake of 2590 might be okay for a young adult but it’s not okay for a 40-plus adult, of which there are many more now than there were then. This affects obesity statistics.

Finally it’s also worth remembering that obesity is not evenly distributed, and an average intake of 2100 kCal could correspond to an average of 2500 in the poorest 20% of the population (where obesity is common) and 1700 kCal in the richest, which is older and thinner. An evenly distributed 2100 kCal will lead to zero obesity over the whole population, but an unevenly distributed 2100 kCal will not. It’s important to look carefully at the variation in the datasets before deciding the average is okay.

Misunderstanding budgets and rates

Let’s consider the 2590 kCal that Monbiot finds as the average intake of adults in 1976, including alcohol and sweets. This is likely wrong, and the average is probably more like 3000 kCal including alcohol and sweets, but let’s go with it for now. Monbiot is looking to see what has changed in our diet over the past 40 years to lead to current rates of obesity, because he is looking for a change in the rate of consumption. But he doesn’t consider that all humans have a budget, and that a small excess of that budget over a long period is what drives obesity. The reality is that today’s obesity rates do not reflect today’s consumption rates, but the steady pattern of consumption over the past 40 years. What made a 55 year old obese today is what they ate in 1976 – when they were 15 – not what the average person eats today. So rather than saying “we eat less today than we did 40 years ago so that can’t be the cause of obesity”, what really matters is what people have been eating for the past 40 years. And the stats Monbiot uses suggest that women, at least, have been eating too much – a healthy adult woman should eat about 2100 kCal, and if the average is 2590 then a woman in 1976 has been at or above her energy intake every year for the past 40 years. It doesn’t matter that a woman’s intake declined to 2100 kCal in 2016, because she has been eating too much for the past 35 years anyway. It’s this budget, not changes over time, which determine the obesity rate now, and Monbiot is wrong to argue that it’s not overeating that has caused the obesity epidemic. Unless he accepts that a woman can eat 2590 kCal every year for 40 years and stay thin, he needs to accept that the problem of obesity is one of British food culture over half a century.

What this means for obesity policy

Somewhat disappointingly and unusually for a Monbiot article, there are no sensible policy prescriptions at the end except “stop shaming fat people.” This isn’t very helpful, and neither is it helpful to dismiss overeating as a cause, since everyone in public health knows that overeating is the cause of obesity. For example, Public Health for England wants to reduce British calorie intake, and the figures on why are disturbing reading. Reducing calorie intake doesn’t require shaming fat people but it does require acknowledgement that British people eat too much. This comes down not to individual willpower but to the food environment in which we all make choices about what to eat. The simplest way, for example, to reduce the amount that people eat is not to give them too much food. But there is simply no way in Britain that you can eat out or buy packaged food products without buying too much food. It is patently obvious that British restaurants serve too much food, that British supermarkets sell food in packages that are too large, and that as a result the only way for British people not to eat too much is through constant acts of will – leaving half the food you paid for, buying only fresh food in small amounts every day (which is only possible in certain wealthy inner city suburbs), and carefully controlling where, when and how you eat. This is possible but it requires either that you move in a very wealthy cultural circle where the environment supports this kind of thing, or that you personally exert constant control over your life. And that latter choice will inevitably end in failure, because constantly controlling every aspect of your food intake in opposition to the environment where you purchase, prepare and consume food is very very difficult.

When you live in Japan you live in a different food environment, which encourages small serving sizes, fresh and raw foods, and low fat and low sugar foods. In Japan you live in a food environment where you are always close to a small local supermarket with convenient opening hours and fresh foods, and where convenience stores sell healthy food in small serving sizes. This means that you can choose to buy small amounts of fresh food as and when you need them, and avoid buying in bulk in a pattern that encourages over consumption. When your food choices fail (for example you have to eat out, or buy junk food) you will have access to a small, healthy serving. If you are a woman you will likely have access to a “woman’s size” or “princess size” that means you can eat the smaller calorific food that your smaller calorific requirements suggest is wisest. It is easy to be thin in Japan, and so most people are thin. Overeating in Japan really genuinely is a choice that you have to choose to make, rather than the default setting. This difference in food environment is simple, obvious and especially noticeable when (as I just did) you hop on a plane to the UK and suddenly find yourself confronted with double helpings of everything, and super markets where everything is “family sized”. The change of food environment forces you to eat more. It’s as simple as that.

What Britain needs is a change in the food environment. And achieving a change in food environment requires first of all recognizing that British people eat too much, and have been eating too much for way too long. Monbiot’s article is an exercise in denialism of that simple fact, and he should change it or retract it.

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