Energy Requirements
Of Adolescents
P.S. Shetty
Adolescence is an important period during which dietary habits that
affect food preferences are acquired.
The energy and nutritional requirements of adolescents are influenced
primarily by the growth spurt that occurs at puberty, and also by the need
to maintain adequate levels of physical activity. Physical activity is essential for normal growth and development and for the psychological wellbeing of adolescents. The energy expenditure and levels of physical activity of young adolescents need to be
consistent with the attainment of proper
development and main-tenance of good
health. Estimates of requirements for
dietary energy of adolescents must
take note of these important needs.
ASSESSMENT
OF NUTRITIONAL
STATUS DURING ADOLESCENCE
the timing of the adolescent spurt and
associated growth changes between
the sexes.
• Data should be collected at sixmonthly intervals because of individual
variations and between-sex variations
in the timing of the adolescent spurt.
Since the rate of growth during adolescence is rapid, six-monthly
increments are sufficiently large to be
detectable and meaningful over and
above the level of measurement errors.
• The timing of the adolescent spurt
and the associated anthro-pometric
changes are maturational phenomena.
Maturational status must therefore be
used to interpret
the meaning of
anthropometric indicators of nutritional
status based on chronological age.
The cut-off values for stunting
(low height-for-age), thinn~ss/underweight (low BMI-for-age), risk of overweight and obesity have been pro-
A recent report has recommended
that Body Mass Index (BMI) be used
as an anthropometric indicator of nutritional status in adolescence. BM 1- posed in the report referred t~ abov~
(Table 1). The anthropometric
varifor-age has been recommended as
ables suggested are height-for-age,
the best anthropometric indicator for
BMI-for-age, and, in the case of obeuse in adolescence. However, the folsity, additional indicators such as skinfold
lowing considerations are important
thickness (triceps and sub-scapular).
in the collection, analysis and interThe reference data recommended are
pretation of anthropometric
data on those collected by the National Cenadolescents' :
tre for Health Statistics (NCHS) in the
• Anthropometric
data need to be USA. Specifically, the first National
presented separately for. bo~s and gir,ls Health and Nutrition Examination Survey
because of differences In Size, and In (NHANES I) and the smoothed and
Cut-off
values
Reference
data: ofNHANES
Anthropometric
variable
= Body Mass Index
<3rd
percentile
BMI-for-age
<5th
>85th
>90th
percentile
percentile
percentile
and
SSKF
TSKF and I, WHO, 1995.
Height-for-age
<-2 Z Cut-off
scores
ded
Values Skin fold
= Subscapular
SSKF
ritional
Anthropometry
of Adolescents
TABLE 1
published percentiles for BMI-for-age
adolescents2 have been recommended
for general use.
ENERGY REQUIREMENTS
ADOLESCENTS
OF
The principle of relying on estimates of energy expenditure rather
than energy intake from diet surveys
to estimate the energy requirements
of children over the age of 10 years,
including the adolescent age group,
has been adopted3. Since body size is
the major determinant of energy requirements, it is necessary to define
the acceptable ranges of body weight.
In adolescents, it is considered realistic to relate energy requirements to
the appropriate weight-for-height rather
than appropriate weight-for-age as in
the case of children below 10 years of
age. Actual heights and median weightfor-height may be used for this purpose. This would allow for the fact
that puberty begins at different ages
in different groups of adolescents.
Estimates of energy requirements
based on body weight alone are likely
to be an approximation, since the differences in body com-position which
will determine the true requirements
are not taken into account. Adolescence is characterised by marked sex
differences in the acquisition of lean
tissue. Boys show a rapid and sustained spurt in lean weight which c?incides with the most rapid growth In
height. In contrast, girls show ~ smaller
spurt in lean weight and acquire more
body fat. Although the variability in
lean weight in adolescents is les.s than
that of body weight, for pragmatlc.reasons, ranges of acceptable welghtfor-height or BM I (weight/heighF) ha,ve
been recommended since the major
deter-minants of energy requirements
of adolescents are body weight and
levels of physical activity.
BASAL METABOLIC RATES OF
ADOLESCENTS
The largest component of ~ot~1
energy expenditure (TEE) of an individual is the Basal Metabolic Rate
(BMR) which usually constitutes between 60-70 per cent of TEE. It can
also be measured readily, with accuracy, under standardised c.onditions.
Since the available and reliable data
on the measurement of habitual TEE
in free living individuals (a?ults ~nd
adolescents) has been limited hitherto, actual measures or predictions
of SMR have gained importance
assessing energy requirements.
in
As in the case of adults, one of
the best predictors of SMR in the age
gr~up 10 to 17 years is also body
weight. At any given weight, variations in height make no difference in
the prediction of SMR of boys and
only a small difference in that of girls3.
The inclusion of height contributes
nothing significant to the SM R predictive equations based on weight. More
recently, a much larger database4 including a larger number of SMR
datapoints from tropical countries have
contributed to a slightly different SMR
predictive equation for 10- to 18-yearolds from that used by the Expert
Consultations.
TOTAL ENERGY EXPENDITURE
OF ADOLESCENTS
Three different methodological
approaches have been generally used
to estimate the free living TEEs of
children and adolescents. These include: (1) Doubly-Labelled Water (DLW)
method, (2) Continuous Heart Rate
Monitoring, and (3) Time and Motion
or Activity Diary techniques. The advantages and limitations of each of
these methods have been reviewed6.
Studies using the DLW technique
in well-nourished
adolescents have
been confined to urban parts of the
USN and the UK8. The available global data on TEE using this technique
have been compiled9 and are summarised in Table 2.
particularly the DLW method, it would
appear that the current estimates12
for energy requirements
of adolescents around the pubertal age may
be somewhat low.
PHYSICAL ACTIVITY LEVELS
(PAL) OF ADOLESCENTS
A relatively simple approach to
estimating TEE and hence energy
requirements was proposed2. The energy cost of various daily activities
was expressed as a proportion of the
SMR for the duration of time and was
termed the physical activity ratio (PAR).
If all activities over a day and its
energy cost were accounted for, the
TEE estimated could then be expressed
as a multiple or factor of the 24·hour
SMR. This ratio, which ex-pressed
the cumulative TEE over 24 hours as
a factor of the BM R over the same
period of time was called the physical
activity level (PAL, that is, TEE/SMR).
Occupational activities and physical
activity-based
lifestyles could then
be attributed different PAL values,
for example, 1.55, 1.78 and 2.15 SM R
as PAL values for male adult indio
viduals engaged in light, moderate
and heavy habitual occupational activities. Attributing the PAL value corresponding to the level of habitual
physical activity and lifestyle of an
individual would enable ready estimation
of TEE (and hence energy requirements) if BMR was either measured
or predicted from body weight. This
factorial approach was recommended
as a means of easy and reliable estimation of energy expenditure and energy requirements3.
and females obtained using either of
the three possible methods for measurement of TEE have been collated'o
while Table 2 summarises the PAL~
based on the DLW method, Table 3
provides PALs obtained by the heart
rate monitoring technique in well-nourished adults. PALs calculated from
the heart rate studies coincided within
5 per cent of those calculated from
DLW studies. The DLW technique
showed no gender differences in the
PALs of well-nourished, urban 13- to
17 -year-olds in industrialised settings
(Table 2). The heart rate monitoring
technique, however, showed a marked
gender difference, with female adolescents showing lower levels of habitual physical activity.
PAL values of adolescents have
also been obtained in both developed
and developing countries using the
time and motion 'and activity diary
method14. In addition to providing estimates of PAL in the adolescent age
group, this latter technique also provides the qualitative information required for the design of intervention
strategies to deal with problems of
low levels of physical activity and predisposition to obesity in this age group.
PHYSICAL ACTIVITY PATTERNS
OF ADOLESCENTS
In developing societies, levels
and patterns of physical activity may
be determined by economic necessity. In addition, socially desirable
activities need to be promoted to further the proper and balanced development of young adults. Although PAL
values obtained by using the DLW
technique provide both a measure of
Studies that have estimated TEE
of adolescents using the heart rate
monitoring method have been collated
PAL values of adolescent males
and reviewed'o. These include data
from developing and industrialised,
11.4
14.5
14.1
1.74
72.0
1.75
9.8
8.1
32
40.7
9.8
BMR
PAL
25.3
19.8
1.68
TEE
1.41
5.7
BMI
31n (Mj d) (year)
14.8
33.3
1.68
9.2
71.5
17.6
26.6
1.73
1.36
8.0
1.63
4.8
6.7
24
26
Age
Black et ai, 1996
Weight
Height
(Mj
d)
(m)
(kg)
developed societies. The compiled data
TABLE
2
Global
Database
on
Total
Energy
Basal
Expenditure
Metabolic
(TEE)
Rates
of
(BMR)
Free
and
Living
Physical
Activity
Levels
(PAL)
Adolescents
Estimated by Doubly-Labelled Water (DLW) Including
indicate that the estimates of TEE
7-12
Age
(expressed per unit body weight) based
on heart rate monitoring coincide quite
well with the data obtained using the
DLW technique in both well-nourished
boys and girls.
Results from studies in adolescents using the time and motion or
diary method to estimate TEE suggest that the estimates approximate
reasonably well with those based on
the DLW method and the heart rate
method, although there appears to be
some tendency to underestimate the
energy expenditures of the older adolescents, especially the males11• Using
these various techniques
for the
estimation
of free Ii'illg
TEE,
7
11.1
PAL
1.75
14.8
1.84
1.61
1.74
Reference
10.8
14.9
Mean
age
1.45
Ramirez
Torun,
1994
Spurr
andand
Reina,
1989
54
24
TABLE
3
Living Adolescent
Males and
Females
Estimated
by Heart
Rate
Monitoring
adolescents. British J Nutr, 24:331-344, 1970.
12. Durnin, J.V.G.A.: Physical activity of adolescents. Acta Paediatrica Scandinavica, 217:133-35,
1971.
13. Banerjee, B. and Saha, N.: Energy intake and
expenditure of Indian schoolboys. British J Nutr,
27:483-90.
14. Guzman, H.P., Cabrera, J.P., Yuchingtat, G.P.,
Almero, E.M., et a/: Energy expenditure and dietary
intake of one- to 19-year-old children. Phillipine J
SC,120:81-105.
NUTRITION
NEWS
the level of habitual physical activity
and the energy requirement of the
adolescent, qualitative data obtained
from time and motion and activity diary techniques provide a useful, critical insight into the types, intensities
and durations of different activities
indulged in by adolescents.
Physical activity is determined
by physiological, behavioural and psychological factors. Lack of time, environmental and safety considerations
and inclement weather are barriers to
participation in physical activity. An
awareness of the benefits of physical
activity is a weak determinant of activity while the enjoyment of activity
is a strong motivator of participation.
Family and friends who act as role
models affect physical activity behaviour
and excessive television watching
deters
adolescents
from
being
physically active. Patterns of physical activity vary with the demo-graphic
characteristics
of the population and
the education and socio-economic
status within the same society. Social,
economic and cultural chracteristics
of different societies also influence
the habitual levels of activity of adolescents and young adults. Physical
activity and fitness are related, and
regular physical activity is an important component of a healthy lifestyle.
Given the nature of societal changes
that favour a more sedentary lifestyle,
more research in, and the design of,
intervention strategies to deal with
the problem of the patterns and levels
of physical activities of adolescents
may reap enormous public health
benefits.
The author is Professor of Human Nutrition at the
London School of Hygiene and Tropical Medicine.
References
1. World Health Organization.: Physical status: the
use and interpretationof anthropometry.WHO Technical
Report Series 854. WHO, Geneva, 1995.
2. Must, A., Dallal, G.E. and Dietz, W.H.: Reference
data for obesity: 85th and 95th percentiles of Body
Mass Index (wt/ht') and triceps skinfold thickness.
Am J Clin Nutr, 53:839-46, 1991.
3. FAO/WHO/UNU. Energy and Protein Requirements. WHO Technical Report Series 724. WHO,
Geneva, 1985.
4. Henry, C.J.K. and Rees, D.G.: New predictive
equations for the estimation of basal metabolic rate
in tropical peoples. Eur J Clin Nutr. 45: 171-85,
1991.
5. Schofield, W.N.: Predicting basal metabolic rate,
new standards and review of previous work. Human
Nutrition: Clinical Nutrition, 39C: 55$41, 1985.
6. Durnin, J.V.G.A.: Methods to assess physical
activity and the energy expended for it by infants
and children. In: Activity, Energy Expenditure and
Energy Requirements of Infants and Children (Eds:
B. Schurch and N.S. Scrimshaw) pp 45-55, Lausanne,
International Dietary Energy Consultation Group,
1990.
7. Bandini, L., Schoeller, D.A. and Dietz, W,H.:
Energy expenditure in obese and non-obese adolescents. Paediatric Research, 27:198-203, 1990.
8. Davies, P.S.W., Livingstone, M.B.E., Prentice,
A.M., Coward, W.A., et a/: Total energy expenditure
during childhood and adolescence. Proceedings of
Nutrition Society, 50:14A, 1991.
9. Black, A.E., Coward, W.A., Cole, T.J. and Prentice,
A.M.: Human energy expenditure in affluent societies: analysis of 574 doubly-labelled water measurements. Eur J Clin Nurr (in press), 1996.
10. Torun, B., Davies, P.S.W., Livingstone, M.B.E.,
Paolisso, M., et a/: Energy requirements and dietary
energy recommendations for children and adolescents one to 18 years old. In: Energy and Protein
Requirements (Eds: B. Schurch, J.C. Waterlow and
N.S. Scrimshaw) Eur J Clin Nutr, Supplement (in
press), 1996.
11. McNaughton, J.W. and Cahn, A.J.: A study of
the food intake and activity of a group of urban
Edited by Anshu Sharma for the Nutrition Foundation of India, C 13 Qutab Institutional Area, New Delhi 110016.
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The sixth Annual Public Health
Forumwas held in London from March
31 to April 3. This was organised by
the London School of Hygiene and
Tropical Medicine and attended by
over 100 scientists of international
repute. The proceedings included 10
plenary sessions and five workshops.
Dr C. Gopalan spoke on: 'Diet-related
non-communicable
disease in developing countries in rapid transition'.
FOUNDATION
NEWS
• Study Circle Lectures
- Professor Priyani Soysa (eminent
paediatrician in Sri Lanka) delivered a
special lecture on: 'Changing spectrum
of malnutrition in children - Lessons
from the Sri Lankan experience' on
April 30.
- Dr K.N. Aggarwal (Professor of
Paediatrics, UCMS, Delhi) spoke on:
'Nutrition and the brain' in his lecture on
May 30.
• The Foundation is grateful to the
following scientists for their valuable
gifts to its library: Dr K.T. Achaya, Dr
Meera Chatterjee.
The Foundation is grateful
to FAG for a matching grant
towards the cost of
this publication