Diet and Health: Diseases and Food 283development due to poor nutrition. At a conservative estimate, this means there
will be 40 million young people added to the total each year.^44
The Obesity Epidemic
As early as 1948, there were medical international groups researching the inci-
dence of obesity in various countries.^45 There were official reports at country level
by the early 1980s,^46 and there has also been a commercial and consumer response
to obesity for even longer.^47 But the grip of international obesity was in fact con-
firmed by the WHO’s Task Force on Obesity in 1998. Today, overweight and
obesity are key risk factors for chronic and non-communicable diseases.^48 In devel-
oping countries obesity is more common amongst people of higher socioeconomic
status and in those living in urban communities. In more affluent countries, it is
associated with lower socioeconomic status, especially amongst women and rural
communities.^49 Historically and biologically, weight gain and fat storage have been
indicators of health and prosperity. Only the rich could afford to get fat. By 2000,
the WHO was expressing alarm that more than 300 million people were defined
as obese, with 750 million overweight, i.e. pre-obese: over a billion people deemed
overweight or obese globally.^50 But by 2003, this figure had been radically revised
upwards when the IASO calculated that up to 1.7 billion people were now over-
weight or obese. The new figures were in part due to more accurate statistics but
also to the recalculation of obesity benchmarks, which acknowledged rising obes-
ity in Asia.^51
Particularly worrying is that extreme degrees of obesity are rising even faster
than the overall epidemic: in 2003, 6.3 per cent of US women, that is 1 in 16, were
morbidly obese, with a body mass index of 40 or more.
Obesity is defined as an excessively high amount of body fat or adipose tissue
in relation to lean body mass. Standards can be determined in several ways, nota-
bly by calculating population averages or by a mathematical formula known as
‘body mass index’ (BMI),^52 a simple index of weight-for-height: a person’s weight
(in kilos) divided by the square of the height in metres (kg/m^2 ). BMI provides, in
the words of the WHO, ‘the most useful, albeit crude, population-level measure of
obesity’. A personal BMI of between 25 and 29.9 is considered overweight; ‘obes-
ity’ means a BMI of 30 and above; a personal BMI of less than 17 is considered
underweight. There is some argument about whether the definition of overweight
(a BMI within the 25–29.9 range) should be lowered from 25 to 23, in which case
tens of millions more people would be considered overweight, and such an unof-
ficial reclassification has led to the disparity between current world obesity fig-
ures.
BMI levels are a useful predictor of risk from degenerative diseases. Unutilized
food energy is stored as fat. Currently, the US National Institutes of Health con-
sider that all adults (aged 18 years or older) who have a BMI of 25 or more are at