It's true - we're all getting too big for our boots

Chris Greener was fourteen when he told his careers teacher he wanted to join the navy when he left school. 'What do you want to be?' asked the teacher. 'The flagpole on a ship?' The teacher had a point - because Chris, though still only fourteen, was already almost two metres tall. Today, at 228 cm, he is Britain's tallest man.
Every decade, the average height of people in Europe grows another centimetre. Every year, more and more truly big people are born. Intriguingly, this does not mean humanity is producing a new super race. In fact, we are returning to what we were like as cavemen. Only now are we losing the effects of generations of poor diet - with dramatic effects. 'We are only now beginning to fulfil our proper potential,' says palaeontologist Professor Chris Stringer. 'We are becoming Cro-Magnons again - the people who lived on this planet 40,000 years ago.'
For most of human history, our ancestors got their food from a wide variety of sources: women gathered herbs, fruits and berries, while men supplemented these with occasional kills of animals (a way of life still adopted by the world's few remaining tribes of hunter- gatherers). One research study found that they based their diet on 85 different wild plants, for example. Then about 9,000 years ago, agriculture was invented - with devastating consequences. Most of the planet's green places have been gradually taken over by farmers, with the result that just three carbohydrate-rich plants - wheat, rice and maize - provide more than half of the calories consumed by the human race today.
This poor diet has had a disastrous effect on human health and physique. Over the centuries we have lived on soups, porridges and breads that have left us underfed and underdeveloped. In one study in Ohio, scientists discovered that when they began to grow corn, healthy hunter-gatherers were turned into sickly, underweight farmers. Tooth decay increased, as did diseases. Far from being one of the blessings of the New World, corn was a public health disaster, according to some anthropologists.
Nevertheless, from then on agriculture spread because a piece of farmed land could support ten times the number of people who had previously lived off it as hunter-gatherers. The fact that most people relying on this system are poorly nourished and stunted has only recently been tackled, even by the world's wealthier nations. Only in Europe, the US and Japan are diets again reflecting the richness of our ancestors' diets.
As a result, the average man in the US is now 179cm, in Holland 180 cm, and in Japan 177 cm. It is a welcome trend, though not without its own problems. Heights may have risen, but the world has not moved on, it seems. A standard bed-length has remained at 190cm since 1860. Even worse, leg-room in planes and trains seems to have shrunk rather than grown, while clothes manufacturers are constantly having to revise their range of products.
The question is: where will it all end? We cannot grow for ever. We must have some programmed upper limit. But what is it? According to Robert Fogel, of University, it could be as much as 193 cm - and we are likely to reach it some time this century.
However, scientists add one note of qualification. Individuals may be growing taller because of improved nutrition, but as a species we are actually shrinking. During the last ice age, 10,000 years ago, members of the human race were slightly rounder and taller - an evolutionary response to the cold. (Large, round bodies are best at keeping in heat.) Since the climate warmed, we appear to have got slightly thinner and smaller, even when properly fed. And as the planet continues to heat up, we may shrink even further. In other words, the growth of human beings could be offset by global warming.