Comment A famous mad professor who has previously called for Britons to starve their children into dwarfism so as to ease strains on the planetary ecosystem has reiterated his arguments, this time insisting that the amount of surplus flab carried by the human race will soon be equivalent to having another half-a-billion people on Earth.
Regular readers will be familiar with Professor Ian Roberts of the London School of Hygiene and Tropical Medicine already: he and his colleague Dr Phil Edwards wrote a paper in 2009 in which they suggested that it would be a good idea for Britons and Americans to model their diet and physique on that of the "lean" Vietnamese, as this would assist in such things as meeting British government carbon pledges. Lightweight Vietnamese people, according to the two scientists, not only need less food but use less energy to move themselves around.
Unfortunately, as we pointed out at the time, this would not merely have been a matter of Britons shedding some flab. In order to match the Vietnamese on weight, Brits would also have to lose four inches or so of height. Extrapolating from Roberts' and Edwards' figures, in fact, the people of the UK would need to shrink to a Hobbit-like stature barely over three feet to meet the more ambitious governmental carbon goals.
Even relatively hefty Vietnamese heights and weights are achieved only by means of serious child malnutrition, so it was clear that Roberts' and Edwards' ideas were not going to be taken seriously (though it was perhaps a little alarming to hear such things from official government-funded experts on public health).
Nothing daunted, however, the two men are back again this week - along with some colleagues - with a new effusion in which they make the flab-equivalent-to-half-a-billion-people assertion.
Accompanying press releases state:
North America has only 6% of the world's population but 34% of the world's biomass mass due to obesity. In contrast Asia has 61% of the world's population but only 13% of the world's biomass due to obesity.
"Our results emphasize the importance of looking at biomass rather than just population numbers when considering the ecological impact of a species, especially humans," says trainee doctor Sarah Walpole, who also worked on the document.
"Everyone accepts that population growth threatens global environmental sustainability – our study shows that population fatness is also a major threat," adds Roberts. "Unless we tackle both population and fatness - our chances are slim."
Unfortunately the entire edifice of their argument is based on the long-discredited Body Mass Index (BMI), a frankly bizarre method of assessing how fat people are which was developed by an obscure Belgian social scientist without any medical qualifications in the early 19th century. The BMI assumes that healthy human mass goes up in proportion to the square of height, a patently absurd suggestion given that human bodies are three-dimensional rather than flat 2D shapes. All other things being equal a human's weight should go up related to the cube of height - and indeed they aren't equal. Any engineer will point out that cross-sectional area in support structures (feet, leg bones etc) needs to go up in direct proportion to weight carried, adding still more heft than a cube law would as height goes up. This is why elephants are not simply scaled-up dogs, and dogs are not simply scaled-up insects - they have proportionally thicker legs and other supporting structures and come out much heavier.
As one would expect, then, it has been confirmed by several recent studies among the taller populations of the modern-day developed nations that a BMI assessment of "overweight" should really be assessed as normal or healthy, while the previous "normal" range ought in fact to be dubbed "underweight", as it has negative health consequences similar to being "obese".
By suggesting that the human race - including the taller peoples - needs to shift into the outmoded BMI "normal" range, Roberts and his fellow public-health experts are advocating a course which would cause more health problems: scarcely what they are paid to do.
Furthermore even by the researchers' ridiculous BMI-based numbers it's apparent that fatness just isn't a big deal:
Using data from the United Nations and World Health Organization, researchers from the London School of Hygiene and Tropical Medicine estimated that the adult human population weights in at 287 million tonnes. 15 millions of which is due to the overweight and 3.5 million due to obesity.
Or in other words, even in their crazy BMI cuckoo world just 6 per cent of the total body weight of the human race is surplus. Not a big issue when you reflect that human numbers are projected to increase by almost 30 per cent in the next few decades, and that most of humanity's carbon emissions have nothing to do with body mass (see below).
And in the real world, where a BMI reading of "overweight" in a tall population actually means "healthy", barely a single percentage point of the human race's mass can be assessed as surplus flab - this is not even worth talking about.
But the allied profs and docs, not content with advocating shortened lifespans due to unhealthily low body weights, go further:
If all countries had the same age-sex BMI distribution as Japan, total biomass would fall by 14.6 million tonnes, a 5% reduction in global biomass or the mass equivalent of 235 million people of world average body mass in 2005. This reduction in biomass would decrease energy requirements by an average of 59 kcal/day per adult living on the planet, which is equivalent to the energy requirement of 107 million adults.
Again, however, Americans or Brits would need to shed not just fat but several inches of height to achieve Japanese-style BMIs. The only way for us to do that would be to starve and malnourish our children, preventing them gowing as tall as their parents.