CHAPTER 1
Energy and macronutrients
1 - ENERGY
This article explains the basis and methodologies underlying the concept of energy balance, which constitutes the cornerstone for devising the ANCs for energy in the French population. First, it describes the concept and general methods. Then it explains how, based on an estimate of resting energy expen- diture and of usual physical activity, it is possible to provide recommendations for a group of adults. Finally, three special issues are dealt with: the elderly, women (either pregnant or lactating) and children. This paper is not a textbook of energy metabolism, nor is it a straightforward translation of the French ver- sion (MARTINet al., 2001), which may be consulted for more information.
1.1 Energy balance and imbalance
Energy balance is achieved when energy intake matches energy expen- diture. If energy intake is less than expenditure, a negative energy balance occurs, accompanied by weight loss, loss of fat mass and an eventual loss of fat free mass.
Similarly, when the energy intake is greater than the amount of energy expended the energy balance is said to be positive. This results in weight gain, principally in the form of fat mass, which can lead to obesity. Positive energy balance and obesity depend to a large extent on a combination of behavioral and environmental factors, which interfere with a biological (genetic) promoting background.
1.1.1 Nutrition
High calorie intake, fatty food consumption, and poor dietary behavior are the main nutritional factors affecting weight control. Several points need to be borne in mind:
– The calorie intake level needed to promote weight gain varies from one subject to another, as does inter-individual energy expenditure. Individuals are not equal faced with the risk of gaining weight (BOGARDUSet al., 1986).
– Lipid intake is a dominant factor in increased calorie intakes, since lipid rich meals tend to be calorie dense. The effect of dietary lipids are particu- larly noticeable in those individuals who have a poor capacity to oxidize lipids, which in turn results in increased amounts being stored as fat (HEINI and WEINSIER, 1997).
– Poor dietary habits (missed breakfast or lunch, snacking outside meals) contribute largely to increased calorie intakes. In a large number of cases, suppressing extra-prandial dietary intake may be enough to restore energy balance again.
– Poor dietary habits, for example impulsive eating (binging), are more com- mon among obese subjects than those of a normal weight.
– Alcohol appears to promote weight gain in certain individuals. This is lin- ked to alcohol’s energy contribution, effect on fat oxidation and effect on impulses, in particular on eating impulses.
– Rapid changes in the dietary habits of migrant populations can promote the development of obesity.
1.1.2 Genetic factors
Genetic factors can play a promoting, and sometimes a determining, role (BOUCHARD, 1997). The degree of genetic predisposition to fatness has been estimated to be between 25 and 40%, and 50% in abdominal obesity. This inherited state means that an individual is more likely to gain weight within a given environment. Apart from the very few cases of single gene defect, obesity is most often the result of multiple genes abnormalities.
Therefore, because of between-individual variation in body composition and of different susceptibity to weight gain, the concept of an ideal body weight and of a unique healthy diet can no longer be promoted.
1.1.3 Physical activity and energy expenditure
A sedentary lifestyle promotes weight gain and obesity. The preservation of fat-free mass by exercise is the only available way of limiting the age-related decrease in resting energy expenditure.
1.2 Components of energy expenditure
Twenty-four hour energy expenditure is the sum of three main components:
basal metabolic rate, resting energy expenditure and energy expended during physical activity.
1.2.1 Basal metabolic rate and resting energy expenditure
Basal metabolic rate refers to the minimal amount of energy needed for basic functioning and maintenance of an organism under very specific condi- tions (12 hour fasting, at rest in a thermoneutral environment). Basal metabolic rate relates to the energy necessary for ion pump functioning, substrate turno- ver, futile cycles, and for maintaining a constant temperature. Basal metabolism represents approximately 60% of 24 hour energy expenditure. Sleeping energy expenditure is approximately 5% less than resting energy expenditure (GOLD- BERGet al., 1988).
1.2.2 Energy expended during physical activity
This incorporates any energy expended in addition to that of basal metabo- lism, due to movement. This may concern all normal daily activities as well as more intense exercise whether due to sport or not. This type of energy expendi- ture varies considerably from one person to another, corresponding to between 15 and 30% of total energy expenditure.
1.2.3 Thermic effects of food
To convert the chemical energy contained within foods into useful energy, foods must be digested and stored, for example in the liver or muscle as glyco- gen, or in the adipose tissue as triglycerides. All of these processes cost energy. The actual cost depends on the biochemical path used. It is estimated that this cost is approximately 5-10% of calories ingested as carbohydrates, 20-30% as proteins and less than 5% as lipids. Under certain conditions (as in carbohydrate-loading) part of the thermic effect of food may be inhibited by beta-blockers, which highlights the role of the sympathetic nervous system in its control. This is called facultative thermogenesis. No matter how this thermic effect is manipulated, it represents only a small portion of total energy expendi- ture (approximately 10%). Any changes in this thermic effect are unlikely to have a significant effect on total energy expenditure or energy balance.
1.2.4 Other factors
It is necessary to consider some less common expenditures, which can in certain circumstances be significant. This is the case for growth. Moreover, because of drug treatments and healing, energy expenditure can be increased significantly, as for example in burned patients. Energy is also expended by the immune system for defense mechanisms and by inflammation, which should be taken into account to estimate a patient’s energy needs.
1.3 Method of evaluating energy balance
1.3.1 Measuring energy expenditure
Many methods can be used to evaluate energy expenditure. Direct or indi- rect calorimetry, which needs specific calorimetric room, is now rarely used (JÉQUIER, 1980). By contrast, indirect calorimetry, which measures respiratory gas exchanges using a ventilated hood, is increasingly used, owing to the gro- wing availability of lighter and less costly systems. The doubly-labeled water
method (RITZ and COWARD, 1995) is now considered as the reference method for measuring the energy needs of an individual, despite its cost due to the use of doubly labeled water with stable isotopes. It is based on the rate with which biological tracers (labeled oxygen — 18O — and labeled hydro- gen — deuterium) are eliminated from the body, both being initially absorbed as
“doubly-labeled water”. The estimation of the differences between their elimina- tion rates allows carbon dioxide gas production and energy expenditure to be calculated. This testing technique does not restrict the activities of the subject under measurement. It therefore allows the energy needs of everyday life (of the elderly, infants or children who are more difficult to measure within the confines of a calorimetry chamber) or those in more extreme conditions (sports, long expeditions) to be determined.
Among indirect methods (heart rate, monitors of exercise intensity…), the factorial method allows both sporadic and daily energy expenditure of an indi- vidual to be calculated by recording the type and length of activities carried out during the day and the unitary energy cost of each. The latter may be expressed in multiples of resting energy expenditure to standardize data between different individuals.
1.3.2 Measuring energy intakes
Energy intakes have been traditionally measured by way of dietary surveys.
However, the latter can be difficult to implement and offer little precision. Their quality depends on the sample of subjects selected, the length of data collec- tion and the technique used (questionnaire, diet history, food weights). The most reliable survey is one carried out over 3 to 7 days (including the week-end) by a trained investigator. Food composition tables, which allow quantities of foods in grams to be transformed into kilocalories or grams of macronutrients, should be reliable and updated regularly. The REGAL tables (FAVIERet al., 1995) and those from Inserm (RENAUD and ATTIE, 1986) provide satisfactory data on foods consumed in France.
1.3.3 Estimating body composition
The analysis of body composition in relation to energy metabolism takes two basic concepts into consideration: tissue (mass) is energy, and all tissue loss (or tissue gain) corresponds to an overall loss of essential chemical energy (or a gain).
Body mass is divided into a metabolically active part (which consumes energy and contains approximately 72% water) and an energy store portion (fat mass which contains virtually no water). This is the classic two-compartment model. The determination of total body water (by labeled water dilution or bioe- lectrical impedance analysis) can be used to calculate the lean body mass and, by comparison with total body weight, the fat mass.
The estimation of body density (either by underwater weighing, skin fold thicknesses or plethysmography) can be used to calculate adiposity — the ratio between fat mass and body weight — and therefore lean body mass in turn.
Dual energy X-ray absorptiometry has become the reference method in determining body composition due to its high level of precision. It also allows segmental analysis and that of three compartments: fat mass, fat-free mass and bone mass. The different methods used to measure body composition comple-
ment one another, and the one chosen depends mainly on the compartment being considered. More complex methods (in vivo neutron activation analysis, potassium 40 counting) or techniques that provide segmental data (magnetic resonance imaging or CT scanning) are sometimes used for research purposes.
1.4 Determining the recommended energy intakes for adults
1.4.1 Principle
The energy needs of an individual are defined as the quantity of energy nee- ded to compensate for energy expended and that needed to ensure a body composition suitable to maintain both long-term good health and a physical activity level adequate for a desirable economic and social status. Energy needs are determined by energy expenditures, rather than from energy intakes. In fact, several studies have shown that dietary intakes can be underestimated by 10- 30% according to the population group studied.
The daily energy expenditure of a given individual, who manages to reproduce the same activities when in a calorimetric chamber, is remarkably constant throu- ghout the year, the coefficient of variation (CV) being only 2.5% on average. In free-living conditions, the CV of daily energy expenditure is 9% on average. On the other hand, the CV between individuals is much more significant (in the order of 12.5% when energy expenditure is expressed per kgs of body weight). This is the reason why recommended energy intakes should only be considered as approximated values for groups of individuals within a certain category.
A factorial approach has been used for revising recommended energy intakes in the UK, Italy and the USA. It has been adopted here also for recom- mended energy intakes for the French population. This approach is based on predicting resting metabolic rate and evaluating energy expended during activi- ties that are commonplace in daily life. These are determined by the specific unitary cost and the average duration spent on each activity per day.
Unitary costs have been determined in everyday life and therefore include the energy expenditure related to the thermic effect of food. In times of extra energy needs, the expenses linked to thermoregulation, pregnancy or breast- feeding should be added to those energy intakes already recommended.
1.4.2 Predicting basal metabolic rate
• Using body composition
Several equations used to predict basal metabolic rate from measurements of body composition have been suggested. Despite the scientific interest in this approach, there are difficulties in measuring body composition, and it therefore does not seem possible to suggest a method that is both reliable and precise in predicting basal metabolism in adults from their body composition.
• Using anthropometric data
Body weight, height, age and sex are frequently used in predicting basal metabolic rate. After examining the different published equations, those of HAR- RISand BENEDICT(1919) and those of BLACKet al. (1996), which consider age as a continuous variable, produce similar results except for subjects of higher weights.
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1.4.3 Determining daily energy expenditure
According to the recommendation of the FAO/WHO/UNU (1985) and the International Dietary Energy Consultative Group, daily energy expenditure is cal- culated by a factorial method using basal metabolic rate and level of physical activity (LPA). The latter can be estimated with the average amount of time spent on common daily activities (an average for the week) and the energy costs of these activities.
• The unitary energy cost of some common activities
A database was drawn from both published studies (where energy expenditure during various activities were measured) and from LPA values suggested in RDAs from the US, Italy, FAO/WHO/UNU (1985) and in JAMESand SCHOFIELD(1990).
All the values have been expressed as multiples of basal metabolic rate in order to accommodate diverse categories of the adult population. These include the average energy cost of 113 activities of daily life. For certain activities, ranges of values are shown in order to take into account the intensity of the activity.
Values are lacking for some professions, in particular those of a manual nature.
The validation of this method has been carried out in relation to the data available and measured using the doubly-labeled water method (BLACK et al., 1996). These calculations show that the level of physical activity and ave- rage daily energy expenditure are dependant on the nature and duration of normal activities, much more so than that of sport (for example, 4 hours of sport per week gives a physical activity level of 6 but this only increases the overall physical activity level by 0.1).
The adult energy expenditures proposed in this book are close to the UK and FAO recommended energy intakes for people of twenty to forty years of age but are from 5 to 11% less when people of 45 to 60 years are considered.
The values are also close to those of the Italian Nutritional RDAs.
• Practical methods of calculating adult energy intakes
Recommended energy intakes (average daily energy expenditures calcula- ted by the factorial method) are established in two ways: directly and in full by the factorial method, or by simplified calculations.
– The direct factorial method
This requires the use of a software package, which will be soon available, containing an index of 113 activities, each divided into several levels of inten- sity. The user determines the average length of time spent on different activities per day over a minimal period of one week. Using the weight, height, age and sex of the person, the software can calculate his or her basal metabolic rate, physical activity level and average daily energy expenditure.
– The simplified factorial method
Besides using the software described above, already prepared tables group activities into six categories (from A to E, corresponding to a certain physical activity level averaging 1.0 – 1.5 – 2.2 – 3.0 – 3.5 – 5 for the adult, plus an addi- tional category for children, see table 1). The average daily length spent on acti- vities contained in each group is counted over a period of one week. The table allows the average physical activity level to be calculated quickly. Another table
(table 2 for men; table 3 for women) allows daily energy expenditure to be cal- culated for each sex according to age (five categories), weight and physical activity level. Corrections for body mass index are suggested. An example of calculation is shown in table 4.
The results of this simpler method vary very little (by 0.3%) from those achie- ved using computer software.
Table 1
Classification of activities within categories according to the level of physical activity (LPA) expressed as a multiple of basal metabolic rate, for a simplified calculation
of daily energy expenditure
Category LPA Activities
A 1 Sleep and nap, resting in lying position
B A 1.5 Sitting position: resting, TV, computer, video game, board or card game, C 1.76 reading, writing, office work, sewing, commuting, eating
C A 2.2 Standing position: washing, walking in the house, cooking, C 2.1 housework, shopping, laboratory work, sales, running machines D A 3.0 Women: walking, gardening or equivalent, gymnastics, yoga
C 2.6 Men: standing and professional manual activities of average intensity (chemical industry, machine-tool industry, woodwork…)
Children: recreation, low activity games
E 3.5 Men: walking, gardening, intensive professional activities (masonry, plastering, car repair…)
Children: normal or rapid walking, active group games (leisure), manual work
F A 5 Sports, highly intensive professional activities (excavation work, forestry C 5.2 work…)
Children: physical education, gymnastics, eurhythmics G C 10 Children: Competitive sports (football, handball, basketball…) A: adults; C: children
Table 2
Average energy expenditure for groups of men according to the level of physical activity, based on a BMI of 22 kg·m–2
Age Weight Height BMR Level of physical activity
(MJ) 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3
55 158 6.13 8.6 9.2 9.8 10.4 11.0 11.7 12.3 12.9 13.5 14.1 20 60 165 6.54 9.2 9.8 10.5 11.1 11.8 12.4 13.1 13.7 14.4 15.0 65 172 6.93 9.7 10.4 11.1 11.8 12.5 13.2 13.9 14.6 15.3 16.0 to 70 178 7.31 10.2 11.0 11.7 12.4 13.2 13.9 14.6 15.4 16.1 16.8 75 185 7.70 10.8 11.6 12.3 13.1 13.9 14.6 15.4 16.2 17.0 17.7 30 80 190 8.05 11.3 12.1 12.9 13.7 14.5 15.3 16.1 16.9 17.7 18.5 85 196 8.42 11.8 12.6 13.5 14.3 15.2 16.0 16.8 17.7 18.5 19.4 years 90 202 8.78 12.3 13.2 14.1 14.9 15.8 16.7 17.6 18.5 19.3 20.2 95 208 9.15 12.8 13.7 14.6 15.6 16.5 17.4 18.3 19.2 20.1 21.0 100 213 9.49 13.3 14.2 15.1 16.1 17.1 18.0 19.0 19.9 20.9 21.8
Table 2 (continued)
Average energy expenditure for groups of men according to the level of physical activity, based on a BMI of 22 kg·m–2
Age Weight Height BMR Level of physical activity
(MJ) 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3
55 158 5.87 8.2 8.8 9.4 10.0 10.6 11.2 11.7 12.3 12.9 13.5 60 165 6.26 8.8 9.4 10.0 10.6 11.3 11.9 12.5 13.1 13.8 14.4 31 65 172 6.64 9.4 10.0 10.6 11.3 12.0 12.6 13.3 13.9 14.6 15.3 70 178 7.00 9.8 10.5 11.2 11.9 12.6 13.3 14.0 14.7 15.4 16.1 to 75 185 7.37 10.3 11.1 11.8 12.5 13.3 14.0 14.8 15.5 16.2 17.0 80 190 7.71 10.8 11.6 12.3 13.1 13.9 14.6 15.4 16.2 17.0 17.7 40 85 196 8.06 11.3 12.1 12.9 13.7 14.5 15.3 16.1 16.9 17.7 18.5 years 90 202 8.41 11.8 12.6 13.5 14.3 15.1 16.0 16.8 17.7 18.5 19.3 95 208 8.76 12.3 13.1 14.0 14.9 15.8 16.6 17.5 18.4 19.3 20.1 100 213 9.08 12.7 13.6 14.5 15.4 16.4 17.3 18.2 19.1 20.0 20.9 55 158 5.68 8.0 8.5 9.1 9.7 10.2 10.8 11.4 11.9 12.5 13.1 60 165 6.05 8.5 9.1 9.7 10.3 10.9 11.5 12.1 12.7 13.3 13.9 41 65 172 6.42 9.0 9.6 10.3 10.9 11.6 12.2 12.9 13.5 14.1 14.8 70 178 6.77 9.4 10.2 10.8 11.5 12.2 12.9 13.5 14.2 14.9 15.6 to 75 185 7.14 10.0 10.7 11.4 12.1 12.8 13.6 14.3 15.0 15.7 16.4 80 190 7.46 10.4 11.2 11.9 12.7 13.4 14.2 14.9 15.7 16.4 17.2 50 85 196 7.80 10.9 11.7 12.5 13.3 14.0 14.8 15.6 16.4 17.2 17.9 years 90 202 8.14 11.4 12.2 13.0 13.8 14.7 15.5 16.3 17.1 17.9 18.7 95 208 8.48 11.9 12.7 13.6 14.4 15.3 16.1 17.0 17.8 18.7 19.5 100 213 8.79 12.3 13.2 14.1 14.9 15.8 16.7 17.6 18.5 19.3 20.2 55 158 5.54 7.8 8.3 8.9 9.4 10.0 10.5 11.1 11.6 12.2 12.7 60 165 5.90 8.3 8.9 9.4 10.0 10.6 11.2 11.8 12.4 13.0 13.6 51 65 172 6.26 8.8 9.4 10.0 10.6 11.3 11.9 12.5 13.1 13.8 14.4 70 178 6.60 9.2 9.9 10.6 11.2 11.9 12.5 13.2 13.9 14.5 15.2 to 75 185 6.95 9.7 10.4 11.1 11.8 12.5 13.2 13.9 14.6 15.3 16.0 80 190 7.27 10.2 10.9 11.6 12.4 13.1 13.8 14.5 15.3 16.0 16.7 60 85 196 7.60 10.6 11.4 12.2 12.9 13.7 14.4 15.2 16.0 16.7 17.5 years 90 202 7.93 11.1 11.9 12.7 13.5 14.3 15.1 15.9 16.7 17.4 18.2 95 208 8.26 11.6 12.4 13.2 14.0 14.9 15.7 16.5 17.3 18.2 19.0 100 213 8.56 12.0 12.9 13.7 14.6 15.4 16.3 17.1 18.0 18.8 19.7 55 158 5.42 7.6 8.1 8.7 9.2 9.8 10.3 10.8 11.4 11.9 12.5 60 165 5.77 8.1 8.7 9.2 9.8 10.4 11.0 11.5 12.1 12.7 13.3 61 65 172 6.12 8.6 9.2 9.8 10.4 11.0 11.6 12.3 12.9 13.5 14.1 70 178 6.46 9.0 9.7 10.3 11.0 11.6 12.3 12.9 13.6 14.2 14.9 to 75 185 6.80 9.5 10.2 10.9 11.6 12.2 12.9 13.6 14.3 15.0 15.7 80 190 7.11 10.0 10.7 11.4 12.1 12.8 13.5 14.2 14.9 15.6 16.4 70 85 196 7.44 10.4 11.2 11.9 12.6 13.4 14.1 14.9 15.6 16.4 17.1 years 90 202 7.76 10.9 11.6 12.4 13.2 14.0 14.7 15.5 16.3 17.1 17.8 95 208 8.08 11.3 12.1 12.9 13.7 14.5 15.4 16.2 17.0 17.8 18.6 100 213 8.38 11.7 12.6 13.4 14.3 15.1 15.9 16.8 17.6 18.4 19.3
Table 3
Average energy expenditure for groups of women according to the level of physical activity, based on a BMI of 22 kg·m–2
Age Weight Height BMR Level of physical activity
(MJ) 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3
45 143 4.71 6.6 7.1 7.5 8.0 8.5 9.0 9.4 9.9 10.4 10.8
50 151 5.09 7.1 7.6 8.2 8.7 9.2 9.7 10.2 10.7 11.2 11.7 20 55 158 5.45 7.6 8.2 8.7 9.3 9.8 10.4 10.9 11.5 12.0 12.5 60 165 5.81 8.1 8.7 9.3 9.9 10.5 11.0 11.6 12.2 12.8 13.2 to 65 172 6.16 8.6 9.3 9.9 10.5 11.1 11.7 12.3 12.9 13.6 14.2 70 178 6.50 9.1 9.8 10.4 11.0 11.7 12.4 13.0 13.7 14.3 15.0 30 75 185 6.85 9.6 10.3 11.0 11.6 12.3 13.0 13.7 14.4 15.1 15.8 years 80 190 7.16 10.0 10.7 11.5 12.2 12.9 13.6 14.3 15.0 15.8 16.5 85 196 7.48 10.5 11.2 12.0 12.7 13.5 14.2 15.0 15.7 16.5 17.2 90 202 7.81 10.9 11.7 12.5 13.3 14.1 14.8 15.6 16.4 17.2 18.0
45 143 4.51 6.3 6.8 7.2 7.7 8.1 8.6 9.0 9.5 9.9 10.4
50 151 4.87 6.8 7.3 7.8 8.3 8.8 9.3 9.8 10.2 10.7 11.2
31 55 158 5.22 7.3 7.8 8.4 8.9 9.4 9.9 10.4 11.0 11.5 12.0
60 165 5.56 7.8 8.3 8.9 9.5 10.0 10.6 11.1 11.7 12.2 12.8 to 65 172 5.90 8.3 8.9 9.4 10.0 10.6 11.2 11.8 12.4 13.0 13.6 70 178 6.22 8.7 9.3 10.0 10.6 11.2 11.8 12.4 13.1 13.7 14.3 40 75 185 6.55 9.2 9.8 10.5 11.1 11.8 12.5 13.1 13.8 14.4 15.1 years 80 190 6.85 9.6 10.3 11.0 11.7 12.3 13.0 13.7 14.4 15.1 15.8 85 196 7.16 10.0 10.8 11.5 12.2 12.9 13.6 14.3 15.0 15.8 16.5 90 202 7.48 10.5 11.2 12.0 12.7 13.5 14.2 15.0 15.7 16.5 17.2
45 143 4.36 6.1 6.6 7.0 7.4 7.9 8.3 8.7 9.2 9.6 10.0
50 151 4.72 6.6 7.1 7.6 8.0 8.5 9.0 9.4 9.9 10.4 10.9
41 55 158 5.05 7.1 7.6 8.1 8.6 9.1 9.6 10.1 10.6 11.1 11.6
60 165 5.38 7.5 8.1 8.6 9.2 9.7 10.2 10.8 11.3 11.8 12.4 to 65 172 5.71 8.0 8.6 9.1 9.7 10.3 10.9 11.4 12.0 12.6 13.1 70 178 6.02 8.4 9.0 9.6 10.2 10.8 11.4 12.0 12.6 13.2 13.9 50 75 185 6.34 8.9 9.5 10.2 10.8 11.4 12.1 12.7 13.3 14.0 14.6 years 80 190 6.63 9.3 10.0 10.6 11.3 11.9 12.6 13.3 13.9 14.6 15.3 85 196 6.93 9.7 10.4 11.1 11.8 12.5 13.2 13.9 14.6 15.3 16.0 90 202 7.24 10.1 10.9 11.6 12.3 13.0 13.8 14.5 15.2 15.9 16.6
45 143 4.25 6.0 6.4 6.8 7.2 7.7 8.1 8.5 8.9 9.4 9.8
50 151 4.60 6.4 6.9 7.4 7.8 8.3 8.7 9.2 9.7 10.1 10.6
51 55 158 4.92 6.9 7.4 7.9 8.4 8.9 9.4 9.8 10.3 10.8 11.3
60 165 5.24 7.3 7.9 8.4 8.9 9.4 10.0 10.5 11.0 11.5 12.1 to 65 172 5.56 7.8 8.4 8.9 9.5 10.0 10.6 11.1 11.7 12.2 12.8 70 178 5.86 8.2 8.8 9.4 10.0 10.6 11.1 11.7 12.3 12.9 13.5 60 75 185 6.18 8.7 9.3 9.9 10.5 11.1 11.7 12.4 13.0 13.6 14.2 years 80 190 6.46 9.0 9.7 10.3 11.0 11.6 12.3 12.9 13.6 14.2 14.9 85 196 6.76 9.5 10.1 10.8 11.5 12.2 12.8 13.5 14.2 14.9 15.5 90 202 7.05 9.9 10.6 11.3 12.0 12.7 13.4 14.1 14.8 15.5 16.2
45 143 4.16 5.8 6.2 6.7 7.1 7.5 7.9 8.3 8.7 9.2 9.6
50 151 4.50 6.3 6.8 7.2 7.7 8.1 8.6 9.0 9.4 9.9 10.3
61 55 158 4.82 6.7 7.2 7.7 8.2 8.7 9.2 9.6 10.1 10.6 11.1
60 165 5.13 7.2 7.7 8.2 8.7 9.2 9.8 10.3 10.8 11.3 11.8 to 65 172 5.44 7.6 8.2 8.7 9.3 9.8 10.3 10.9 11.4 12.0 12.5 70 178 5.74 8.0 8.6 9.2 9.8 10.3 10.9 11.5 12.1 12.6 13.2 70 75 185 6.05 8.5 9.1 9.7 10.3 10.9 11.5 12.1 12.7 13.3 13.9 years 80 190 6.32 8.9 9.5 10.1 10.8 11.4 12.0 12.6 13.3 13.9 14.5 85 196 6.61 9.3 9.9 10.6 11.2 11.9 12.6 13.2 13.9 14.5 15.2 90 202 6.90 9.7 10.4 11.0 11.7 12.4 13.1 13.8 14.5 15.2 15.9
Table 4 Example of a calculation of the level of physical activity from mean durations of various activities classified within six categories ActivitiesActivitiesActivitiesActivitiesActivitiesActivities ABCDEF DurationLPADurationLPADurationLPADurationLPADurationLPADurationLPA (h·d–1)(h·d–1)(h·d–1)(h·d–1)(h·d–1)(h·d–1) 110.06210.09210.12510.14610.208 220.12520.18320.25020.29220.416 330.18830.27630.37530.43730.624 440.25040.36840.50040.58340.832 550.31350.46050.62550.72951.042 60.25060.37560.55260.75060.875 70.29270.43770.64470.87571.021 80.33380.50080.73681.00081.166 90.37590.56390.82891.125 100.417100.620100.920101.250 110.458110.688111.012111.375 120.500120.750121.104121.500 85262124 0.3330.3130.1830.7500.2920.2082.08
Table 4
Instructions for use
1. Calculate average daily duration devoted to each category listed in table 1.
2. Determine the corresponding Level of Physical Activity (LPA) values for each category in table 4 and sum to obtain global LPA.
3. Look up this value in table 2(for men) or table 3(for women).
4. Correct to take BMI into account if it differs from 22 kg·m–2 (EE lower for fatty mass), by multi- plying the previous value by a correcting factor resulting from the following formula:
1 – (BMI – 22) * 0.01.
An example is given for a man aged 25 y, weight 75 kg, height 1.8 m, and achieving on average: 8 h sleep, 5 h for activity B, 2 h for activity C, 6 h for activity D, 2 h for activity E and 1 hr for activity F.
The last lines of table 4indicate that his LPA is 2.08. For an LPA of 2.10 and a weight of 75 kg, table 2gives an energy expenditure of about 16.2 MJ.
Correction for LPA 2.08: 16.18 * 2.08 / 2.10 = 16.05 MJ BMI = 23.1 kg·m–2
Correcting factor for BMI: 1 – (22 – 23.1) * 0.01 = 0.989
DEE = 16.05 MJ * 0.989 = 15.87 MJ·d–1 The energy ANC for this individual is thus approximately 15.87 MJ·d–1.
1.5 Recommendations for the elderly
Maintaining a satisfactory nutritional state is important in the overall health condition of the older person (CYNOBERet al., 2000). While reducing the preva- lence of obesity is a key issue in the adult population, management of mal- nutrition is a major objective of ANCs for the elderly.
The estimated nutritional needs of the elderly have until now only concerned this population broadly (for example all those above 51 years in US data, and those greater than 60 years in previously recommended nutrient intakes for the French population). Given the growth of this population sector, particularly those of 85 years and above, these recommended figures should be re-consi- dered. Physiological changes, linked with age, influence dietary intake. Appetite tends to be reduced, as is the ability to compensate following a period of over or under-feeding. Taste, smell and thirst senses are often affected.
It is important that energy intakes should cover the needs of very different people due to variability in health status and physical activity amongst them.
The majority of studies contain people of 60 to 85 years and few include higher age classes. They often concern those people who are most active and who have higher energy needs.
Experts recommend carrying out studies on the more fragile or sick elderly persons and studies more representative of those living at home.
The energy needs of elderly persons are often under-estimated, especially when physical activity is important. It is known that resting metabolism decreases by 2% per decade (POEHLMAN, 1992), but specific equations to calculate the basal metabolic rate of the elderly from anthropometric data are needed. It appears that age has all but very little influence on the thermic effect of food. Decreased energy-expenditure is linked to corresponding reduction in physical activity. The level and type of physical activity needed to maintain good health should be evaluated. These are probably higher than previously thought. The physical acti- vity level established for men is between 1.52 and 1.75 and between 1.43 and
1.80 for women. Moreover, a meta-analysis shows a moderate reduction of physical activity with age. It is therefore reasonable to suggest intakes greater than 1.5 times resting metabolic rate (formerly recommended) especially for those who remain active. It is impossible to make recommendation for those above 80 years of age.
1.6 Recommended energy intakes for pregnant and breast-feeding women
Pregnancy is a period of adaptation of energy metabolism leading to the birth of a new being and changes in the woman’s body composition that are necessary for the pregnancy itself and the preparation for later breast-feeding.
The energy needs of pregnancy can be calculated using a factorial approach, by adding the cost of the fetus development, the cost of the mother’s changes in body composition and the extra-energy expended for bearing the child.
In developed countries, the total cost of a normal pregnancy is estimated at around 80 Mcalories. This leads to the recommendation that daily energy intake should be increased by approximately 150 kcal during the first trimester and by 350 kcal during the following two in order to meet this added energy expenditure.
24-hour energy expenditure and basal metabolic rate increase in a noti- ceable way from the 24thweek of gestation reaching a level that is 20% higher at the 36thweek in comparison to that before pregnancy. There is no change in the cost of unitary activities during pregnancy. However, physical activity level varies widely and is influenced by the cultural and socioeconomic background of the family. The increased dietary intake observed during pregnancy is far from the energy costs calculated by the factorial method. Besides some resi- dual errors, which are possible in calculating energy intake or expenditure, it should be noted that a physiological adaptation, specific to pregnancy, may lead to more efficient use of available energy than is generally admitted.
Concerning lactation, the milky secretion is affected very little by nutritional conditions. The protein and lipid contents in milk remain almost constant no matter what the geographical origin or nutritional state of the woman (PRENTICE et al., 1996). The energy value of milk is approximately 0.61 kcals per gram. The milk energy cost of lactation is estimated at 525 kcals per day. Current data shows that basal metabolism is not changed. Dietary consumption is increased slightly (10 to 380 kcals per day). As during pregnancy, this is insufficient to cover the calculated expenses. This suggests that the current estimated energy needs are possibly too great or that the maternal body makes up the difference (by using the energy stores).
1.7 Energy for children
The principles of the determination of energy requirements for children are similar to those used for adults. In addition, for all groups, the energy stored in tissues during growth has been taken into account. For newborns, ANCs are shown in table 5. For children aged 3-9 y, there are few data on levels of physi- cal activities, so that only three levels have been considered (table 6). For chil-
Table 5 ANCs for energy for newborns fed formulas, from birth to age 1year BoysGirls AgeEE (months)(kJ·kg–1·d–1)WeightGainStoredANCsWeightGainStoredANCs (kg)(g·d–1)energy(MJ·d–1)(kg)(g·d–1)energy(MJ·d–1) (kJ·d–1) 12933.80294701.63.6264261.5 22934.75354721.94.35294261.7 33055.60305682.35.05244522.0 43186.35213762.45.70193312.1 53267.00172592.56.35162722.3 63397.45152052.76.95152342.6 73597.90131173.07.40111092.8 83598.35131173.17.85111092.9 93598.75131173.38.25111093.0 103939.1511793.78.6510883.5 113939.5011793.89.0010883.6 123939.8511794.09.3510883.8
Table 6 Energy expenditure, stored energy and ANCs for energy for children aged 2 to 9years ANCs according to the level of AgeWeightAverageEnergyEnergyStoredphysical activity (LPA) (years)(kg)LPAexpenditureexpenditureenergy (kJ·kg–1·d–1)(MJ·d–1)(kJ·d–1)lowmedianhigh LPALPALPA Boys 212.21.53864.7424.54.85.1 314.61.53485.1424.85.15.4 416.91.553285.6425.35.65.9 519.01.63136.0425.76.06.4 6211.753457.3426.97.37.7 7241.753217.7427.37.88.2 8271.753038.2847.88.38.8 9301.752898.7848.28.89.3 Girls 211.81.53704.4424.14.44.7 314.21.53344.7424.54.85.1 416.51.553155.2424.95.25.6 518.51.63035.6425.35.76.0 621.21.753146.7426.36.77.1 7241.752967.1636.77.27.6 8271.752817.6847.27.78.1 9301.752618.1847.78.28.6
Table 7 ANCs for energy for boys aged 10 to 18years according to the level of physical activity (LPA) ANCs according to LPAWeightHeightBMIBMRGrowth (kg)(m)(kg·m–2)MJ·d–1(kJ·d–1) 1.41.51.61.71.81.92.02.12.2 301.3516.54.93937.37.88.38.79.29.710.210.711.2 351.4316.85.34107.88.38.99.49.910.511.011.512.0 401.5017.65.74188.38.99.510.010.611.211.712.313.3 451.5618.26.05108.99.510.110.711.311.912.613.113.7 501.6318.76.44479.410.010.711.311.912.613.213.914.5 551.6919.26.83479.810.511.211.812.513.213.914.515.2 601.7320.07.125110.210.911.612.413.113.814.515.215.9 651.7521.17.520910.711.412.212.913.714.415.115.916.6 701.8021.57.820911.212.012.713.514.315.115.916.717.4 751.8522.08.216711.612.513.314.114.915.716.617.418.2 801.9022.08.616712.113.013.914.715.616.417.318.119.0 The principle of calculation is the same as for adults (see tables1and 4).
Table 8 ANCs for energy for girls aged 10 to 18years according to the level of physical activity (LPA) ANCs according to LPA WeightHeightBMIBMRGrowth (kg)(m)(kg·m–2)MJ·d–1(kJ·d–1) 1.41.51.61.71.81.92.02.12.2 301.3516.54.65026.97.37.88.28.79.29.610.110.5 351.4416.84.95027.47.88.38.89.39.810.310.811.3 401.5017.65.27127.98.59.09.510.010.511.011.612.1 451.5618.55.41178.89.39.910.411.011.512.112.613.1 501.6119.95.75028.59.19.610.210.811.312.012.513.0 551.62215.94198.69.29.910.411.011.612.212.813.3 601.7020.86.21268.89.410.010.611.311.912.513.113.7 651.7222.06.41269.19.710.311.011.612.313.013.514.2 701.7822.16.7849.410.110.711.412.112.713.414.114.7 The principle of calculation is the same as for adults (see tables1and 4).
