(The research in the second half of this post was used as the basis for an article in The Independent of 28th December 2014)

Recent reports have commented on the quite rapid fall in energy use in the UK, even in a period of economic growth. In ‘Peak Stuff’ I advanced the suggestion that all developed societies will eventually use fewer material resources and energy. I hypothesised that the UK had already begun to ‘dematerialise’ and its demand for energy, for minerals and for food had actually started to fall in the early part of the last decade.

The evidence in support of ‘Peak Stuff’ in respect to food, as well as energy, is now very strong indeed. The latest edition of the long running official survey of food purchasing suggests that average consumption of calories from all types of food and drink fell another 0.7% in 2013 and is now about 9% below the level of the early years of this century. People in the UK are unambiguously eating less food than they used to. To make the obvious point, as the economy has begun to recover, food consumption hasn’t gone up, any more than energy use has increased. Environmentalists who call for an end to growth are pushing an out-of-date thesis; increased economist prosperity isn’t incompatible with a decent world for all 10bn to live in.

Chart 1

Source: Family Food ONS, 2014 — Source: *Family Food* ONS, 2014

Chart 1 gives the average calorific value of food purchases per person per day from 2001/2 until 2013. Survey of the calorific value of people’s food have been going on for much longer and we have reasonable, but incomplete, UK data from about 1945. The early surveys only measured food bought for home consumption and excluded meals out, as well as confectionery and alcohol.

Chart 2 (copied directly from Family Food, 2014)

Nevertheless, the overall pattern is very clear: people in the 1950s ate much more food than we do today. The chart below suggests that average calorie intake from food eaten in the home (and excluding external purchases of food, alcoholic drink and confectionery) was over 2600 a day until the mid-1960s. The comparable figure today is less than 1900. The higher figure a generation ago is unsurprising because jobs much more frequently involved manual labour, homes were not centrally heated (raising the metabolic rate needed to keep warm) and individuals had much less access to cars for their transport needs.

Food production, manufacture and distribution probably accounts for about 20% of the global warming footprint of a developed economy, with the single most important contribution arising from the manufacture and use of nitrogenous fertilisers. We might hypothesise that the slow decline of per capita consumption is tending to reduce the impact of agriculture on the ecosystem.

But to get closer to certainty, we need to be sure that the reduction in the overall amount being eaten is not counterbalanced by a rise in the consumption of the most resource-intensive food, beef and other meats. If meat eating were going up sharply it might more than balance the cut in average calorie intakes because it is so much more ecologically damaging that other forms of food production.

Chart 3

Is meat-eating going up? No, and the fall is as fast as overall food purchases. Meat eating fell 10% in the period from 2001/2 to 2013. These figures are expressed in grams of food purchased per week rather than calories.

UK data on falling food consumption always surprises people because of its apparent conflict with rising obesity. Most of us assume that we are typically consuming far more food than we actually need and, as a direct result, people’s weight is continuing to increase. This may still be true but the rate of increase seems to be levelling off.

Chart 4

What else does the latest official survey in Family Food show? Some of the conclusions are extremely surprising. Although overall energy intake, averaging around 2192 calories per person including children, is about 5% higher than the amount that would leave people neither losing nor gaining weight, the pattern among different demographic segments is strikingly diverse. The top conclusions are

· Poorer people are now eating much less than richer groups. In 2001/2, average energy intakes didn’t vary very much between income groups. The poorer half of the population had calorie consumption 99% of the richer half. By 2013, that had changed. The poorer 50% now eat significantly less than the wealthier half. In 2001/2 the difference between the average food intake in the poorer and richer halves was 27 calories. In the most recent year it was 165.

· The greatest difference is between the bottom and the top 10%. In 2001/2, the poorest decile had a calorie intake of 97% of the richest decile. In 2013, this had fallen to 87%.

· This wouldn’t matter very much if everybody still had enough to eat. But by 2013, the poorest decile’s food intake was less than 86% of what it was in 2001/2, meaning that the people in this group are not eating enough – on average – to maintain their weight. The government says that the average person (this mixes young and old, male and female so is only an approximate measure) should have an intake of about 2080 calories. The poorest 10% now only get 1997 calories, or 4% less than typically required to maintain weight.

· By contrast, the top decile eat 110% of what is needed to keep weight constant.

Chart 5

To summarise, poorer people used to eat almost as much as richer groups. This is no longer the case. Although the numbers aren’t entirely consistent from year to year, we appear to have seen a significant relative and absolute fall in the food consumption of the less well off. Perhaps this is because of rising food prices, perhaps because of falling incomes. The percentage of their income that the poorest decile use to buy food has barely changed at around 16%. This is, of course, a much higher percentage than for richer groups.

Also striking is the swing in food consumption between young and old.

· In households headed by a person under 30, the average calorie intake is now less than 1750, including food eaten away from home. This far less than is likely to be needed to maintain of the average person in that household.

· The average calorie intake of people in this group has fallen by over 22% since 2001/2, much faster than the 9% cut among the population as a whole. We cannot know for sure whether this is because of choice or because of a shortage of income. But this age group has seen the greatest contraction in income over the last decade or so and it is not unreasonable to suggest that falling incomes are meaning some young people do not have enough cash to eat as much as they need.

· Contrast this with the experience of household headed by someone from 65-74. People in this group are eating an average of 2600 calories, greatly in excess of what they need for a stable weight. And this may be related to the fact that this demographic segment has experienced the greatest increase in income over the last decade or so.

· People in households headed by someone over 75 are actually eating more than they did in 2001/2 and their consumption is now also well above the recommended level.

Consumption is swinging away from the younger and poorer groups and towards the older and richer.

How does these cuts of the data affect the ‘Peak Stuff’ hypothesis? The obvious riposte is to say that food consumption is falling because of declining disposable income. As (if?) the economy returns to providing rising living standards for people, food intake will start rising again. My response is to say that a) all income groups are cutting their calories, not just people who are income constrained and b) calories consumption has been trending downwards for fifty years or more, through GNP growth and GNP stagnation.

What about the marked difference in calorie trends between young and old? Here I’d say that although much of this bifurcation seems to be do with income differentials (with the old substantially increasing their share of the income cake over the last decade) it probably also reflects a change in food culture. Perhaps the young don’t binge: the data shows their food and their alcohol consumption falling sharply. Whether the Peak Stuff theory is right or wrong, young British people are certainly acting as though material consumption is less important to them than in the past.