Free Fat, Fate, and Disease : Why we are losing the war against obesity and chronic disease by Mark Hanson Peter Gluckman Page A

school as they did when they were children themselves. It is true that in the UK, for example, many local education authorities have sold off fields where children could engage in sport or just run around. Very often they are valuable pieces of real estate and the cash helps to balance the books of the local council. In addition, the number of children who walk or cycle to school is far lower than it used to be. Parents worry about traffic or potential molestation by paedophiles or just that, if their children are making their own way home from school, it is hard to know exactly what they might get up to on the way. There is no doubting theseriousness of the road traffic accident worry and very few Western cities have adequate cycle lanes or paths which would allow children to go to and from school in relative safety. The statistics, however, do not bear out the worry about other threats—it seems that children are no more likely to be murdered, abducted, or sexually assaulted today than they were a generation ago.
    But of course children don’t need acres of space in order to exercise. What about good old-fashioned physical education lessons? These still take place in many schools and are prescribed in most curricula. They were never the most popular lessons among many children. Now they are deeply unfashionable with some groups, who effectively refuse to participate. The difference in perception occurs in the early puberty years when boys and girls tend to separate in their attitudes. If there is a training element which seems linked to sporting or other prowess, the activity can often be sold to the boys in the class, but for the girls the concept of changing into unappealing or revealing sports kit and then getting hot and sweaty is not alluring.
    But what about life outside school? Recent studies suggest that this too may be important, although the reliability of such studies is uncertain. There are often very big differences between what people say they do and what they actually do, as measured by using electronic monitoring equipment. Nevertheless it is sobering to note that some researchers found that children who undertook a high level of physical activity at school were far less likely to be physically active at home. In contrast, those children who appeared to do relatively little physical exercise at school were more likely to go out to play football or join dance classes outside school hours. So in the end the net effect may be the same for both groups.
    This is not to say that children do not differ in the overall amounts of physical activity in which they engage over the courseof a week and that possibly this may link to how well they control their appetites and body weight. But what these studies do suggest is that the setting for physical activity is established relatively early in the lives of our children. If we force them to do more exercise in one setting—say at school—will they do less in another? Once again we get the feeling that merely focusing on exercise levels in children is not the whole answer. Exercise may help but it may also be too late to produce a permanent change, at least in some people. One of our major themes pops up again—people vary.
    The energy that we expend in deliberate physical activity is only part of the story. Jogging or weightlifting is all very well and certainly burns up calories, but recent research suggests a surprising way in which we also use calories. Ever noticed that the nervous, twitchy child in the class, who is always fidgeting and shifting in his or her seat, dropping things on the floor and picking them up, is also likely to be the thin child? They are not going anywhere or doing anything very useful but they are burning up a lot of energy in the process. This type of apparently minor activity uses a lot of energy every day, but once again it balances out. If we exercise in the gym on the way home from work, we will probably fidget less later when we are