Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
An in-depth analysis of energy requirements for different age groups, including infants, children, adolescents, pregnant women, and adults. It covers measurement of total energy expenditure, equations to predict energy requirements, and recommendations for physical activity. The report also discusses energy requirements for pregnancy and lactation, and proposes differentiating requirements for populations with varying levels of physical activity.
What you will learn
Typology: Lecture notes
1 / 103
This page cannot be seen from the preview
Don't miss anything!
F O O D A N D N U T R I T I O N T E C H N I C A L R E P O R T S E R I E S
ISSN 1813-
Report of a Joint FAO/WHO/UNU Expert Consultation
Rome, 17–24 October 2001
(low) Level of requirement (high)
Energy
Average requirement
Average requirement
Percentage of individuals
(low intake) Usual level of intake (high intake)
1.0 1.
0 0
Probability that stipulated intake is inadequate
for a randomly selected individual Probability that stipulated intake is excessive
for a randomly selected individual
FOREWORD
Assessing the calorie and nutrient requirements of human beings, with the greatest possible degree of accuracy, is one of the most important and central mandates of the Food and Agriculture Organization of the United Nations (FAO). Since 1948, FAO has convened numerous expert groups in the field of nutrition to collate, evaluate and interpret current scientific knowledge in order to derive estimates of human energy requirements and use these estimates to provide recommendations to people and policy-makers. The World Health Organization (WHO) began its collaboration with FAO on this important work in the early 1950s, while the United Nations University (UNU) joined the initiative in
This important publication is the final report of the most recent expert group meeting, the Joint FAO/WHO/UNU Expert Consultation on Human Energy Requirements, convened in October 2001 at FAO headquarters in Rome, Italy. The primary purpose of the expert meetings on nutrient requirements has remained the same throughout the years: to give advice on scientific issues related to food energy and nutrient requirements and to formulate recommendations for action. Various expert groups have contributed principles for determining and applying general requirements, which have been adopted worldwide. The global scientific community has continued to embrace the advice on requirements that was first published by FAO alone and later in collaboration with WHO. The FAO/WHO recommendations have reflected the state of knowledge at particular points in time, and have also influenced research agendas and methodologies over the years. In fact, the FAO/WHO recommendations are currently utilized in virtually all countries, and nutrient requirement reports are among the most frequently referenced and most sought-after publications in both organizations. Estimates of human energy requirements are essential for assessing whether food supplies are adequate to meet a population’s nutritional needs. Such estimates are also essential in assessing the proportion and absolute number of undernourished people worldwide. The recommendations derived from these estimates assist governments to monitor nutrition programmes and plan development activities. The recommendations also help with the specific formulation of planning at the national level for agricultural production, food supplies and the mobilization and distribution of emergency food aid. FAO has an ongoing mandate to review these assessments periodically – particularly as new research findings emerge – and to produce estimates using the highest possible degree of accuracy based on recent scientific advances and developments in the field. FAO publishes this report on behalf of the three United Nations (UN) agencies (FAO/WHO/UNU) that organized the consultation. We would like to express our gratitude to the members of the expert consultation for their contribution to this important report, as well as to the numerous participants of the working groups. The work of these groups preceded the expert consultation and served as the foundation for discussions and exchange during the meeting. Thanks are also due to Dr E. Kennedy, who very skilfully chaired the expert consultation, and to Dr B. Torun for his commitment to the role of rapporteur and for his contribution to early drafts of this report. We thank all the participants, as well as the non-participating experts who drafted background papers as part of the preparatory process for the expert consultation. These background papers will be published in a special issue of Public Health Nutrition in 2005, thereby providing a more detailed peer-reviewed literature source for many of the ongoing debates on the various topics discussed during the consultation. We would also like to express our special gratitude to the FAO staff members who constituted the Secretariat and completed much of the follow-up work that culminated in this report, in particular the staff of the Nutrition Planning and Evaluation Service (ESNA), P. Shetty, R. Weisell, and B. Burlingame, as well as G. Kennedy, F. Martinez Nocito, T. Ballard and J. Shaw who assisted as consultants both during and after the expert consultation.
Kraisid Tontisirin Hartwig de Haen Director Assistant Director-General Food and Nutrition Division Economic and Social Department
PREFACE
The purpose of the expert consultations on human energy requirements convened by FAO, WHO and, more recently, UNU is to advise the Directors-General on scientific issues related to food energy, including requirements, so that appropriate recommendations for action can be formulated. It is hence important that during the process of determining energy requirements the question of “requirements for what?” be constantly borne in mind. While biological scientists are generally concerned with the physiological basis of estimating requirements, it is also necessary to be aware of the practical applications of these recommendations for estimating the energy requirements and food needs of populations worldwide. The principal objective of expert consultations on human energy requirements is to provide international agencies and their member countries with the necessary tools for addressing practical questions, such as assessing the adequacy of food supplies and the numbers of people who do not attain energy adequacy, drawing up targets for food production and informing national food and nutrition policy and planning. The recommendations and guidelines that result from these consultations will serve to enable governments and organizations to plan, monitor and evaluate nutrition programmes and policies better. They will also help Member Nations to develop estimates of requirements appropriate for local conditions and for direct application in their countries. It is important to remember that while developed countries are able to constitute their own committees of experts who can make recommendations on energy and nutrient requirements for their populations, the majority of humanity in the developing world relies largely on UN agencies such as FAO. Hence, the development of pragmatic recommendations by expert committees convened by UN agencies, which are based on sound scientific evidence and have practical relevance to the conditions prevailing in the developing world, is paramount. The entire process leading up to the convening of an expert group and the resulting consultation is highly formalized and follows a number of required protocols. For the first time, FAO adopted a two- stage process, which started with convening working groups in those areas where it believed that new scientific knowledge existed that might influence the current recommendations for energy needs. The second stage of the process was the expert consultation itself. The rationale behind convening the working groups was that many of the scientific questions could be dealt with by experts in the areas concerned, even though the participation of those experts at the consultation per se was uncertain owing to the need to provide a globally representative consultative panel. Working groups would also facilitate discussions, as any contentious issues could be debated and settled before the expert meeting, which would benefit from the results of such discussions. Accordingly, working groups met from 27 June to 5 July 2001 at FAO headquarters in Rome, several months before the expert meeting in October 2001. Three of the working groups focused primarily on energy requirements throughout the life cycle and related to two important sub-populations – infants and children, and pregnant and lactating women – for which substantial scientific advances had been made. These working groups were on: 1) energy (and protein) requirements of infants and preschool children; 2) energy (and protein) requirements of pregnancy and lactation; and 3) analytical issues in food energy and composition: energy in food labelling, including regulatory and trade issues, which looked at food energy values. An additional working group was constituted to provide documentation on methodologies for energy balance and energy requirements, but it was felt that – given the nature of the task – there was no need for this group to meet, although their background documents were available to the expert consultation. The chairpersons of all the working groups on energy were invited to the expert consultation to present a summary of the deliberations and recommendations of their groups and to advise the experts. Background papers were commissioned, peer-reviewed and made available to both the pre-consultation working groups and the experts who met for the consultation. The entire process of pre-consultation activities and the consultation itself went smoothly, despite a few hitches that were largely the result of the unhappy events of 11 September 2001, which prevented some of the invited experts from coming to Rome to join the consultative process. Lists of the participants in the various working group sessions, and those invited as experts to the consultation are included as Annex 1 of this report. Annex 2 provides details of the authors and
One of the other recommendations that arose from the deliberations of the working group on analytical issues in food energy and composition, which was subsequently endorsed by the experts, was to convene a meeting to deliberate on food energy values. The objective was to ensure harmony between the expected adoption of new energy requirement values from this consultation, which are based solely on energy expenditure measurements or estimates, and energy requirements based on food intake measurements alone. FAO thus convened a Technical Workshop on Food Energy – Methods of Analysis and Conversion Factors, which was held in Rome from 3 to 6 December 2002. The report of this workshop was published as FAO Food and Nutrition Paper No. 77 in 2003, which complements the present report. As part of the post-consultation activities in preparation for the release of the expert report, it was decided to produce an updated, Windows-compatible and user-friendly software application for the purpose of calculating population energy requirements and food needs. After the 1981 joint expert consultation report was released (WHO, 1985), FAO sponsored the development of a manual and software package (James and Schofield, 1990), recognizing that less attention had hitherto been paid to the matter of how to apply the requirements to practical food and nutrition planning. The success of this 1990 user’s manual, which was sponsored by FAO and published by Oxford University Press, was constrained because it was a priced publication that was available separately from the 1985 joint expert report. For the 2001 consultation, it was decided to make the new software widely and readily available by releasing it alongside the report. FAO therefore had to find an organization that would assist us in developing such a product to be released at the same time as the expert report in 2004. Early discussions were conducted with the United States Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, with the objective of developing the software and making it available as a downloadable version alongside CDC’s popular EpiNut software. However, CDC was unable to collaborate in this venture, so other partners had to be sought. The Division of Nutrition, Institute of Population Health and Clinical Research at Bangalore, India and its Dean, Dr A. Kurpad, identified Jenesys Technologies, a software applications firm in India, which collaborated alongside the institute in the development of the software package and accompanying manual (Annex 4). This is now available on CD-ROM. For the first time, the software package is being issued together with the expert report in order to ensure that those interested in the report’s recommendations have the means to investigate and ensure their practical applicability, as well as to benefit from the two outputs’ complementarity. The user’s manual and software application for calculating population energy requirements and food needs thus represent a further milestone in FAO’s continued involvement in both the theoretical and the practical issues related to human energy requirements. This expert consultation was convened nearly two decades after the last expert group met to deliberate on energy and protein requirements in 1981. In the interim, the International Dietary Energy Consultancy Group (IDECG), sponsored jointly by UNU and the International Union of Nutritional Sciences (IUNS), filled the lacuna by convening meetings to discuss important developments in this area. The IDECG meeting in London in 1994 on Energy and Protein Requirements (whose proceedings were published in European Journal of Clinical Nutrition Vol. 50, Supplement 1 in February 1996) was a seminal meeting that provided much of the preparatory background for this expert consultation. We would like to acknowledge and pay our tribute to the late, Dr Beat Schurch who, as Executive Secretary of IDECG, was the quiet engine behind this invaluable contribution to the advancement and dissemination of nutrition knowledge. FAO and WHO benefited greatly from IDECG’s work and publications, in particular its review of human energy and protein requirements in 1994. While FAO was organizing the 2001 expert consultation, Beat Schurch knew that he was sick but planned to attend both the consultation and the working groups that preceded it. Unfortunately, his illness progressed more quickly than had been anticipated, and he had to decline the invitation. He approached his illness and its culmination with the same equanimity with which he approached most matters and wished the group well. His contribution and friendship will be sorely missed.
Prakash Shetty Chief Nutrition Planning, Assessment & Evaluation Service (ESNA) Food & Nutrition Division
Introduction
1. INTRODUCTION
Since 1949, the Food and Agriculture Organization of the United Nations (FAO) and, since the early 1950s, the World Health Organization (WHO) have convened groups of experts to evaluate current scientific knowledge in order to define the energy requirements of humans and propose dietary energy recommendations for populations. The purpose of this information is to assist FAO and WHO in implementing their programmes. The United Nations University (UNU) became part of this joint initiative in 1981. The reports of these expert meetings (see the list of References at the end of this chapter) have become important guidelines on energy in human nutrition for academic scientists, nutritionists, physicians and other health workers, as well as for planners and policy-makers in both the agriculture and health sectors throughout the world. New scientific knowledge generated in the 20 years since the last expert consultation was held prompted FAO, WHO and UNU to assemble a new expert consultation to make recommendations for energy requirements of populations throughout the life cycle (WHO, 1985). This consultation took place from 17 to 24 October 2001 at FAO headquarters in Rome. Its mandate was to revise and update the conclusions and recommendations of the preceding consultation, which was convened in 1981 and whose report was published in 1985. In preparation for the forthcoming expert consultation, well- known scientists with demonstrated expertise in this area of work were asked to examine and write background papers on various topics that required revision and updating. Several of the authors and other leading scientists constituted working groups that met in Rome in June 2001 to discuss and analyse critically the contents of the background papers, which were subsequently modified following the working group suggestions. The modified papers, the working groups’ conclusions and other relevant documents were provided to all members of the expert consultation for analysis and consideration in their deliberations.^1 Dr Eileen Kennedy was elected to chair this expert consultation, and Dr Benjamin Torun to be the rapporteur. Several conclusions and recommendations were the immediate results, while a number of topics were identified as requiring further research and analysis before the experts could finalize their recommendations. The rapporteur and other members of the consultation were given the task of pursuing the pending issues with assistance from the FAO Secretariat, and additional working papers were commissioned. This laborious task went on until the end of 2003, when almost all questions had been answered and gaps filled and the rapporteur was able to prepare the final draft for examination and approval by the other experts from the consultation. This report is the final result of those efforts.
1.1 WHAT IS NEW IN THIS REPORT? Although the basic principles set forth in previous expert meetings have withstood the test of time, several modifications are proposed in this report. Members of the expert consultation and participants in the working groups recognize and accept the responsibility for proposing these modifications, and for the implications that they will have on health, agriculture, the food industry, economic planning, international aid and social programmes related to food and nutrition. It is their belief that the conclusions and recommendations in this report are well grounded, given the current state of the best scientific knowledge. A critical appraisal of their application will be the final proof of their accuracy, applicability and appropriateness.
The new concepts and recommendations set forth in this report include:
x calculation of energy requirements for all ages, based on measurements and estimates of total daily energy expenditure and on energy needs for growth, pregnancy and lactation; x in the light of new data, modification of the requirements and dietary energy recommendations for infants and for older children and adolescents, in order to correct previous overestimations for the former and underestimations for the latter;
(^1) Annex 1 gives the names of participants in the working groups and expert consultation. Annex 2 lists the titles
and authors of the background documents.
Introduction
of physical activity are the main causes of nutritional problems, there is an urgent need for governments, in partnership with all relevant stakeholders, to integrate strategies that promote healthy diets and regular physical activity in all relevant policies and programmes, including those designed to fight undernutrition. Both undernutrition and obesity are preventable, as has been demonstrated by countries with successful programmes. In addition to health promotion, nutrition education and relevant agricultural and food policies, effective food and nutrition programmes must include community action to overcome the environmental, social and economic constraints that limit the improvement of access to food, and to promote better dietary quality and life style practices that encourage a physically active life.
FAO. 1950. Calorie requirements: Report of the Committee on Calorie Requirements. FAO Nutritional Studies No. 5. Rome. FAO. 1957. Calorie requirements: Report of the Second Committee on Calorie Requirements. FAO Nutritional Studies No. 15. Rome. FAO/WHO. 1973. Energy and protein requirements: Report of a joint FAO/WHO ad hoc expert committee. FAO Nutrition Meetings Report Series No. 52. WHO Technical Report Series No. 522. Rome and Geneva. WHO. 1985. Energy and protein requirements: Report of a joint FAO/WHO/UNU expert consultation. WHO Technical Report Series No. 724. Geneva.
Human energy requirements: Report of a Joint FAO/WHO/UNU Expert Consultation
2. PRINCIPLES AND DEFINITIONS
Human energy requirements are estimated from measures of energy expenditure plus the additional energy needs for growth, pregnancy and lactation. Recommendations for dietary energy intake from food must satisfy these requirements for the attainment and maintenance of optimal health, physiological function and well-being. The latter (i.e. well-being) depends not only on health, but also on the ability to satisfy the demands imposed by society and the environment, as well as all the other energy-demanding activities that fulfil individual needs. Energy balance is achieved when input (i.e. dietary energy intake) is equal to output (i.e. total energy expenditure), plus the energy cost of growth in childhood and pregnancy, or the energy cost to produce milk during lactation. When energy balance is maintained over a prolonged period, an individual is considered to be in a steady state. This can include short periods during which the day- to-day balance between intake and expenditure does not occur. An optimal steady state is achieved when energy intake compensates for total energy expenditure and allows for adequate growth in children, and pregnancy and lactation in women, without imposing metabolic, physiological or behavioural restrictions that limit the full expression of a person’s biological, social and economic potential. Within certain limits, humans can adapt to transient or enduring changes in energy intake through possible physiological and behavioural responses related to energy expenditure and/or changes in growth. Energy balance is maintained, and a new steady state is then achieved. However, adjustments to low or high energy intakes may sometimes entail biological and behavioural penalties, such as reduced growth velocity, loss of lean body mass, excessive accumulation of body fat, increased risk of disease, forced rest periods, and physical or social limitations in performing certain activities and tasks. Some of these adjustments are important and may even increase the chances of survival in times of food scarcity.
2.1 DEFINITIONS An adequate, healthy diet must satisfy human needs for energy and all essential nutrients. Furthermore, dietary energy needs and recommendations cannot be considered in isolation of other nutrients in the diet, as the lack of one will influence the others. Thus, the following definitions are based on the assumption that requirements for energy will be fulfilled through the consumption of a diet that satisfies all nutrient needs.
Energy requirement is the amount of food energy needed to balance energy expenditure in order to maintain body size, body composition and a level of necessary and desirable physical activity consistent with long-term good health. This includes the energy needed for the optimal growth and development of children, for the deposition of tissues during pregnancy, and for the secretion of milk during lactation consistent with the good health of mother and child.
The recommended level of dietary energy intake for a population group is the mean energy requirement of the healthy, well-nourished individuals who constitute that group.
Based on these definitions, a main objective for the assessment of energy requirements is the prescription of dietary energy intakes that are compatible with long-term good health. Therefore, the levels of energy intake recommended by this expert consultation are based on estimates of the requirements of healthy, well-nourished individuals. It is recognized that some populations have particular public health characteristics that are part of their usual, “normal” life. Foremost among these are population groups in many developing countries where there are numerous infants and children who suffer from mild to moderate degrees of malnutrition and who experience frequent episodes of infectious diseases, mostly diarrhoeal and respiratory infections. Special considerations are made in this report for such sub-populations.
Human energy requirements: Report of a Joint FAO/WHO/UNU Expert Consultation 66
6
Probability that a particular energy intake is inadequate or excessive for an individual*
Principles and definitions
substrates determined by chemical analysis, or estimated from appropriate food composition tables. A recent related report from a FAO technical workshop provides more information on this topic (FAO, 2003).
2.3 COMPONENTS OF ENERGY REQUIREMENTS Human beings need energy for the following:
x Basal metabolism. This comprises a series of functions that are essential for life, such as cell function and replacement; the synthesis, secretion and metabolism of enzymes and hormones to transport proteins and other substances and molecules; the maintenance of body temperature; uninterrupted work of cardiac and respiratory muscles; and brain function. The amount of energy used for basal metabolism in a period of time is called the basal metabolic rate ( BMR ), and is measured under standard conditions that include being awake in the supine position after ten to 12 hours of fasting and eight hours of physical rest, and being in a state of mental relaxation in an ambient environmental temperature that does not elicit heat-generating or heat-dissipating processes. Depending on age and lifestyle, BMR represents 45 to 70 percent of daily total energy expenditure, and it is determined mainly by the individual’s age, gender, body size and body composition. x Metabolic response to food. Eating requires energy for the ingestion and digestion of food, and for the absorption, transport, interconversion, oxidation and deposition of nutrients. These metabolic processes increase heat production and oxygen consumption, and are known by terms such as dietary-induced thermogenesis , specific dynamic action of food and thermic effect of feeding. The metabolic response to food increases total energy expenditure by about 10 percent of the BMR over a 24-hour period in individuals eating a mixed diet. x Physical activity. This is the most variable and, after BMR, the second largest component of daily energy expenditure. Humans perform obligatory and discretionary physical activities. Obligatory activities can seldom be avoided within a given setting, and they are imposed on the individual by economic, cultural or societal demands. The term “obligatory” is more comprehensive than the term “occupational” that was used in the 1985 report (WHO, 1985) because, in addition to occupational work, obligatory activities include daily activities such as going to school, tending to the home and family and other demands made on children and adults by their economic, social and cultural environment. Discretionary activities, although not socially or economically essential, are important for health, well-being and a good quality of life in general. They include the regular practice of physical activity for fitness and health; the performance of optional household tasks that may contribute to family comfort and well-being; and the engagement in individually and socially desirable activities for personal enjoyment, social interaction and community development. x Growth. The energy cost of growth has two components: 1) the energy needed to synthesize growing tissues; and 2) the energy deposited in those tissues. The energy cost of growth is about 35 percent of total energy requirement during the first three months of age, falls rapidly to about 5 percent at 12 months and about 3 percent in the second year, remains at 1 to 2 percent until mid-adolescence, and is negligible in the late teens. x Pregnancy. During pregnancy, extra energy is needed for the growth of the foetus, placenta and various maternal tissues, such as in the uterus, breasts and fat stores, as well as for changes in maternal metabolism and the increase in maternal effort at rest and during physical activity. x Lactation. The energy cost of lactation has two components: 1) the energy content of the milk secreted; and 2) the energy required to produce that milk. Well-nourished lactating women can derive part of this additional requirement from body fat stores accumulated during pregnancy.
2.4 CALCULATION OF ENERGY REQUIREMENTS The total energy expenditure of free-living persons can be measured using the doubly labelled water technique (DLW) or other methods that give comparable results. Among these, individually calibrated heart rate monitoring has been successfully validated. Using these methods, measurements of total energy expenditure over a 24-hour period include the metabolic response to food and the energy cost
Principles and definitions
2.5 RECOMMENDATIONS FOR PHYSICAL ACTIVITY A certain amount of activity must be performed regularly in order to maintain overall health and fitness,^3 to achieve energy balance and to reduce the risk of developing obesity and associated diseases, most of which are associated with a sedentary lifestyle. This expert consultation therefore endorsed the proposition that recommendations for dietary energy intake must be accompanied by recommendations for an appropriate level of habitual physical activity. This report provides guidelines for desirable physical activity levels, and for the duration, frequency and intensity of physical exercise as recommended by various organizations with expertise in physical activity and health. It also emphasizes that appropriate types and amounts of physical activity can be carried out during the performance of either obligatory or discretionary activities and that recommendations must take into account the cultural, social and environmental characteristics of the target population.
2.6 GLOSSARY AND ABBREVIATIONS In addition to those defined in the preceding sections, the following terms and abbreviations are used in this report. They are consistent with the definitions used in other related WHO and FAO documents (FAO, 2003; James and Schofield 1990; WHO, 1995).
Basal metabolic rate (BMR) : The minimal rate of energy expenditure compatible with life. It is measured in the supine position under standard conditions of rest, fasting, immobility, thermoneutrality and mental relaxation. Depending on its use, the rate is usually expressed per minute, per hour or per 24 hours.
Body mass index (BMI) : The indicator of weight adequacy in relation to height of older children, adolescents and adults. It is calculated as weight (in kilograms) divided by height (in meters), squared. The acceptable range for adults is 18.5 to 24.9, and for children it varies with age.
Doubly labelled water (DLW) technique : A method used to measure the average total energy expenditure of free-living individuals over several days (usually 10 to 14), based on the disappearance of a dose of water enriched with the stable isotopes 2 H and 18 O.
Energy requirement (ER) : The amount of food energy needed to balance energy expenditure in order to maintain body size, body composition and a level of necessary and desirable physical activity, and to allow optimal growth and development of children, deposition of tissues during pregnancy, and secretion of milk during lactation, consistent with long-term good health. For healthy, well-nourished adults, it is equivalent to total energy expenditure. There are additional energy needs to support growth in children and in women during pregnancy, and for milk production during lactation.
Heart rate monitoring (HRM) : A method to measure the daily energy expenditure of free-living individuals, based on the relationship of heart rate and oxygen consumption and on minute-by-minute monitoring of heart rate.
Total energy expenditure (TEE) : The energy spent, on average, in a 24-hour period by an individual or a group of individuals. By definition, it reflects the average amount of energy spent in a typical day, but it is not the exact amount of energy spent each and every day.
Physical activity level (PAL) : TEE for 24 hours expressed as a multiple of BMR, and calculated as TEE/BMR for 24 hours. In adult men and non-pregnant, non-lactating women, BMR times PAL is equal to TEE or the daily energy requirement.
(^3) The term “fitness” encompasses cardiorespiratory health, appropriate body composition (including fat
distribution), muscular strength, endurance and flexibility. Fitness can generally be described as the ability to perform moderate to vigorous physical activity without becoming excessively tired.
Human energy requirements: Report of a Joint FAO/WHO/UNU Expert Consultation
Physical activity ratio (PAR) : The energy cost of an activity per unit of time (usually a minute or an hour) expressed as a multiple of BMR. It is calculated as energy spent in an activity/BMR, for the selected time unit.
FAO. 2003. Food energy – methods of analysis and conversion factors. Report of a technical workshop. FAO Food and Nutrition Paper No. 77. Rome. James, W.P.T. & Schofield, E.C. 1990. Human energy requirements. A manual for planners and nutritionists. Oxford, UK, Oxford Medical Publications under arrangement with FAO. WHO. 1985. Energy and protein requirements: Report of a joint FAO/WHO/UNU expert consultation. WHO Technical Report Series No. 724. Geneva. WHO. 1995. Physical status: The use and interpretation of anthropometry. Report of a WHO expert committee. WHO Technical Report Series No. 854. Geneva.
Human energy requirements: Report of a Joint FAO/WHO/UNU Expert Consultation
between TEE and body weight (Butte et al., 2000b). TEE was significantly affected by age, gender, weight and length. Age, weight and height were all good predictors of TEE, with a slight advantage for weight. Because the three parameters were highly correlated (r = 0.91 – 0.96), and there were no independent effects of age, gender and length when weight was used as the predictor, the latter was used to develop the following equation (Butte, 2001), which is graphically displayed in Figure 3.1.
TEE (MJ/day) = – 0.416 + 0.371 kg; n = 320, r = 0.85, see = 0.456 MJ/day (109 kcal/day) TEE (kcal/day) = – 99.4 + 88.6 kg (n = number of observations; see = standard error of estimate)
FIGURE 3. Linear relationship and 95 percent confidence and prediction intervals of equation to predict TEE from body weight in healthy infants, one to 24 months old
TEE (MJ/d) = – 0.416 + 0.371 kg; n = 320, r = 0.85, see = 0.456 MJ/d ( 109 kcal/d ). TEE (kcal/d) = – 99.4 + 88.6 kg. Source: Butte, 2001.
The relationship between TEE and weight in the 13 studies mentioned in Section 3.1 was explored using the mean values for TEE and body weight. Some studies included longitudinal or cross- sectional data at various ages throughout infancy, or from groups of either breastfed or formula-fed infants. A total of 40 sets of TEE and body weight values, weighted for sample size, gave the following linear regression equation, which does not differ significantly from that shown above:
TEE (MJ/day) = – 0.399 + 0.369 kg; n = 40, r = 0.99, see = 0.527 MJ/day (126 kcal/day) TEE (kcal/day) = – 95.4 + 88.3 kg
As the equation was derived from the mean values of each study, the regression coefficient and standard error of estimate (see) do not reflect individual variation.
3.2.1 Breastfed and formula-fed infants Four studies with breastfed and formula-fed infants showed that the formula-fed infants had higher TEE during the first year of life (Butte et al., 1990; Butte et al., 2000b; Jiang et al., 1998; Davies et al., 1990). Compared with their breastfed counterparts, formula-fed infants had on average 12, 7, 6 and 3 percent higher TEE at three, six, nine and 12 months of age, respectively. At 18 and 24 months, there was no difference between infants who still received breastmilk and those who did not (Butte, 2001). The equations to predict TEE from body weight are as follows:
J (^) JJJJ
J J J J J
J
J J
J
J
J J
J J J
J J
J
J J^ JJ J
J J J
J J J J
J J
J
J J JJJ J
J J
J
J J
J
J J J
J J
JJ
J J J
J J J J J
J
J J
J J J
J J
J J J
J J
J (^) J
J
J J
J
J
J JJ J JJ J JJ
J
J
J
J JJ J
J
J
J J J
J J
J
J
J
J J
J J
J J
JJ
J J
J J J
J
JJ
J J
J (^) J J
J
J
J J
J (^) J J J J
J
J JJ
J J
J J JJ
JJ
J
J
J
J
J
J J
J J
J
J J
J J
J
J
J
J
J
J
J
J J (^) JJ (^) JJJJ J
JJ J J (^) J (^) J (^) J
J J
J J
J
JJ^ J
J
J J
J J
J
J
J J
J J
J J J
J
J J
JJJ J
J
J
J
J J J J
J
J JJ (^) J
J
J J
J J
J J
JJ
J
J
J
J
J J
J
J
J (^) J
J
J J (^) J J
J J J
J
J J J J
J J
J
J J J
J J
J
J (^) J J
JJ
J J
J J
J
J
J J
J
J
J
J
J J
J J J
J J J
J J J
J (^) J
J J
J
J
J J
J
J
JJ J
J J J J
J
J J
0
1000
2000
3000
4000
5000
6000
0
200
400
600
800
1000
1200
1400
4 6 8 10 12 14
TEE (kJ/d) TEE (kcal/d)
Weight (kg)
Linear regression 95% Confidence interval 95% Prediction interval
Energy requirements of infants from birth to 12 months
Breastfed: TEE (MJ/day) = – 0.635 + 0.388 kg; n = 195, r = 0.87, see = 0.453 MJ/day (108 kcal/day) TEE (kcal/day) = – 152.0 + 92.8 kg
Formula-fed: TEE (MJ/day) = – 0.122 + 0.346 kg; n = 125, r = 0.85, see = 0.463 MJ/day (110 kcal/day) TEE (kcal/day) = – 29.0 + 82.6 kg
3.3 ENERGY NEEDS FOR GROWTH Growth is a sensitive indicator of whether an infant’s energy requirements are satisfied. Energy demands for growth constitute about 35 percent of the total energy requirement during the first three months of life (40 percent in the first month), this proportion is halved in the next three months (i.e. to about 17.5 percent), and further reduced to one-third of that during the ensuing six months (i.e. to less than 6 percent) and to only 3 percent at 12 months. Energy for growth falls to less than 2 percent of daily requirements in the second year, remains between 1 and 2 percent until mid-adolescence, and gradually disappears by 20 years of age. Energy needs for growth have two components: 1) the energy used to synthesize growing tissues, which is part of the total energy expenditure measured with DLW; and 2) the energy deposited in those tissues, basically as fat and protein, because carbohydrate content is insignificant. Hence, energy requirements in infancy can be calculated by adding the energy deposited in growing tissues to TEE. Much previous knowledge on the energy cost of growth was based on studies in pre-term infants or in children recovering from malnutrition, and used energy balance and the two-component body composition techniques (WHO, 1985; Butte, Wong and Garza, 1989). Methodological advances have allowed a better assessment of body composition changes during infancy through serial measurements of total body electrical conductivity (de Bruin et al., 1998), or with a multi-component body composition model based on measurements of total body water, total body potassium and bone mineral content (Butte et al., 2000a). This permits calculation of the gains in protein and fat, as well as of the corresponding energy deposition assuming that the energy equivalents of protein and fat are 23.6 and 38.7 kJ/g (5.65 and 9.25 kcal/g), respectively. As Table 3.1 shows, energy accrued per gram of weight gain decreased from approximately 26 kJ (6.3 kcal) in the first three months of life to about 10 kJ (2.3 kcal) at nine to 12 months.
TABLE 3. Protein, fat and energy deposition during growth in the first year of life Age Energy accrued in normal growth* months
Protein gain g/d
Fat mass gain g/d
Weight gain g/d (^) kJ/g kcal/g Boys 0–3 2.6 19.6 32.7 25.1 6. 3–6 2.3 3.9 17.7 11.6 2. 6–9 2.3 0.5 11.8 6.2 1. 9–12 1.6 1.7 9.1 11.4 2. Girls 0–3 2.2 19.7 31.1 26.2 6. 3–6 1.9 5.8 17.3 15.6 3. 6–9 2.0 0.8 10.6 7.4 1. 9–12 1.8 1.1 8.7 9.8 2. ***** (^) Energy equivalents: 1 g protein = 23.6 kJ ( 5.65 kcal ); 1 g fat = 38.7 kJ ( 9.25 kcal ). Source: Butte et al., 2000a.
