HUMAN ENERGETICS - Energy in Nature and Society - page 124

Schofield, and James 1985). The data set included adults
of different stature and different weight-for-height, but
nearly all its data came from Western nations, where
unlike in poor countries, adequate nutrition led to full
expression of physical growth potential. Moreover, nearly
half of the data came from pre-1945 studies of Italian
men. Naturally, doubts were raised about the set's global
validity for deriving predictive regressive equations of
BMR as was done in the 1985 report on food require-
ments (FAO 1985).
Henry and Rees (1991) found that Schofield's equa-
tions overpredicted the BMRs of people in the tropics,
with the differences being largest for adults over 30 years
of age. The average overprediction was 9% for males
(ranging from 1.5% for Maya to 22.4% for Ceylonese)
and 5.4% for females (up to 12.9% for Indian women).
Explanations for these differences range from varying
abilities in producing muscle relaxation to BMR-
lowering effects of warm climate. The latter conclusion
is supported by BMR changes in individuals moving
from temperate to tropical climates. Piers and Shetty
(1993) revisited these disparities by measuring BMRs of
Indian women. They found that Schofield's equations
overpredicted the basal metabolism by 9.2%; they also
overpredicted the BMRs of American women and young
Australians, and they appeared to be accurate only for
predicting European BMRs (Piers et al. 1997).
New equations were generated by Ramirez-Zea
(2002), but the latest expert consultation concluded
that they are not robust enough to justify the abandon-
ment of Schofield's set (FAO 2004). Inclusion of body
height has no effect on improving the fits of these simple
linear equations, but in order to avoid excessively high
recommendations of average food energy intakes, desir-

able body weights for given heights (rather than actual
means or medians) should be used in these regressions
in any country where obesity is widespread, notably in
North America (Pellett 1990). The regression for men
30-60 years old,

BMR ð MJ = day Þ¼ 0 : 048 kg þ 3 : 653 ;

explains only 36% of variance; for women same age the
equation

BMR ð MJ = day Þ¼ 0 : 034 kg þ 3 : 538

accounts for 49% of variance.
The regression fits are much better for children
(r ¼ 0 : 97 for those less than 3 years old) and adolescents
(r ¼ 0 : 9 for teenage boys). For males and females whose
adult masses are, respectively, 65 kg and 55 kg, daily
BMRs progress from about 700 kJ at birth to peaks of
about 7.5 MJ (male) and 6.0 MJ (female) during the
late teens and early twenties, then gradually decline to
levels about 20% below the adult maxima after age 60.
The total energy expenditure (TEE) of newborns (whose
BMR is difficult to measure) is just over 3 W/kg, and the
BMRs of 1-2-year-old girls and boys averages, respec-
tively, 2.68 W/kg and 2.75 W/kg (FAO 2004). By the
age of 10 the rate dips below 2.0 W/kg, and five years
later it declines to < 1.5 W/kg (fig. 5.3). The average
decadal decreases are 2.9% for normal-weight males and
2.0% for normal-weight females (FAO 2004). By the
late teens the rates are only slightly above the adult level,
and after staying more or less stable for 40 years, they re-
new their decline after age 60. By age 70 the fire of life,
at just 1 W/kg, burns at less than half the rate at birth.