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8. SUMMARY OF REQUIREMENTS FOR ENERGY AND PROTEIN

8.1 Introduction

The aim of this section is to summarize the estimates derived in section 6, on the principles discussed in sections 4 and 5. The derivation of corrections to be applied for different diets is described in section 7.

8.1.1 Precision of estimates

The calculations in section 6 have been made with a greater degree of precision, or apparent precision, than can ever be useful in practice. In this section the figures are rounded off, usually to 2 digits only.

8.1.2 Age ranges

The age ranges used for adults are those discussed in section 3.5. For children, somewhat narrower ranges have been adopted. Even so, they embrace a very wide span of body weights. For example, for boys 3–5 years old, the acceptable range of body weight extends from 12 kg (3 years, 5th centile) to 23 kg (5 years, 95th centile). Therefore, if greater precision is needed, the more detailed tables in section 6 should be consulted.

8.1.3 Relation to body weight

Both energy and protein requirements are related to body weight, although in a different way. The estimates given in the following tables relate only to subjects whose weight is within the acceptable range for height (adults) or age (children). The approach to be adopted for those outside these ranges is discussed in section 9. It has been emphasized (section 3.5) that within the acceptable ranges, the estimates of requirements may be based either on the actual weight, or on the median weight for height or age (“normative” estimates, see section 3.5.1), according to the objectives for which they are to be used.

It should be stressed, however, that for children, in whom the range of body weight within acceptable limits for age (10th–90th centiles) is very wide, the normative approach will under - or overestimate the requirements of those at the extremes of the distribution.

8.1.4 Corrections for characteristics of the diet

For both energy and protein a correction may have to be made for digestibility, and in the case of protein, for quality also (section 7). In contrast to previous practice, it is recommended that when comparisons are being made between requirements and dietary intakes, the corrections should be applied to the diet rather than to the values for requirements. The reason for this is that it will facilitate aggregated comparisons between intakes and requirements, for example for a family unit, when different members of the family consume different diets (see section 11.4). However, there are situations in which the user may find it more convenient to make the correction in the traditional way, i.e., by adjusting the estimate of requirement.

The method of making these corrections is summarized in Table 51.

8.2 Adults

The energy and protein requirements of adult men and women in three age ranges are shown in Tables 42–47.

8.2.1 Energy

The energy requirement is determined in these tables from the body weight and the level of physical activity, as defined by the BMR factor. Values of the BMR factor appropriate for different general levels of physical activity have been given in Table 15, and some examples have been shown in Tables 9–14. When requirements are being estimated for particular groups, the user may in the first instance choose the most appropriate example as a guideline. However, it is recommended that, wherever possible, the estimates should be based on actual “profile” studies of the average time spent on different types of activity, particularly where there may be seasonal changes. With this information, the appropriate value for the BMR factor can be calculated by the methods given in section 6.

The figures in Tables 42–47 were derived as estimates of energy expenditure. They may be equated, without further correction, to average requirements for dietary energy intake from a standard diet to which it is appropriate to apply the usual Atwater factors. For diets that contain large amounts of “unavailable” energy (section 7.1), a correction has to be applied (see section 8.6).

8.2.2 Protein

For adults the protein requirement per kg body weight is considered to be the same for both sexes at all ages and body weights within the acceptable range. The value accepted for the safe level of intake is 0.75 g per kg per day, in terms of proteins with the digestibility of milk or egg.

8.3 Adolescents

Because of the variable timing of the adolescent growth spurt, it is recommended that estimates of requirements should be based on weight rather than age, provided that the weight is within the acceptable range of weight for height. Age ranges are given in Table 48 as a general guide in cases where body weights are not known.

8.3.1 Energy

Full details are given in Table 28 and Annex 7. The requirements in Table 48 are based on the Consultation's estimate of desirable levels of physical activity which is so important for the development of children and adolescents. When they are even more active physically, their requirements will naturally be increased.

Table 42. Daily average energy requirement and safe level of protein intake for men aged 18–30 years
Weight
(kg)
BMR/kgaDaily energy requirementb according to BMR factor indicated:Safe level
of protein
intakec
(g/day)
(kcalth)(kJ)1.4 BMR1.6 BMR1.8 BMR2.0 BMR2.2 BMR
(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)
5029121.32 0508 5002 3009 7002 60010 9002 90012 1003 20013 30037.5
5527.5115.12 1008 9002 40010 1002 70011 4003 00012 7003 30013 90041   
6026.5110.82 2509 3002 55010 6002 85012 0003 15013 3003 45014 60045   
6526108.72 3509 9002 70011 3003 00012 7003 30014 1003 70015 50049   
7025104.62 45010 2002 80011 7003 15013 2003 50014 6003 85016 10052.5
7524.5102.52 55010 8002 90012 3003 30013 8003 65015 4004 00016 90056   
8024100.42 65011 2003 05012 9003 40014 5003 80016 1004 20017 70060   

a Values of BMR/kg are presented for ease of calculation by those who wish to use different BMR factors.
b Calculated for each weight from the equations in Table 5 (rounded values).
c At 0.75 g per kg of protein with the quality and digestibility of milk or egg.

Table 43. Daily average energy requirement and safe level of protein intake for men aged 30–60 years
Weight
(kg)
BMR/kgaDaily energy requirementb according to BMR factor indicated:Safe level
of protein
intakec
(g/day)
(kcalth)(kJ)1.4 BMR1.6 BMR1.8 BMR2.0 BMR2.2 BMR
(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)
5029121.32 0508 5002 3509 7002 65010 9002 90012 1003 20013 30037.5
5527.5115.12 1008 9002 45010 1002 75011 4003 05012 7003 35013 90041   
6026108.72 2009 1002 50010 4002 85011 7003 15013 0003 45014 30045   
6525104.62 3009 5002 60010 9002 95012 2003 25013 6003 60015 00049   
7024100.42 3509 8002 70011 2003 05012 6003 40014 1003 70015 50052.5
7523.598.322 45010 3002 80011 8003 15013 3003 50014 7003 85016 20056   
8022.594.142 55010 5002 90012 0003 25013 5003 60015 1004 00016 60060   

a Values of BMR/kg are presented for ease of calculation by those who wish to use different BMR factors.
b Calculated for each weight from the equations in Table 5 (rounded values).
c At 0.75 g per kg of protein with the quality and digestibility of milk or egg.

Table 44. Daily average energy requirement and safe level of protein intake for men over the age of 60 years
Weight
(kg)
BMR/kgaDaily energy requirementb according to BMR factor indicated:Safe level
of protein
intakec
(g/day)
(kcalth)(kJ)1.4 BMR1.6 BMR1.8 BMR2.0 BMR2.2 BMR
(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)
502396.231 6506 7001 8507 7002 1008 7002 3009 6002 55010 60037.5
5522.594.141 7007 2001 9508 3002 2009 3002 45010 4002 70011 40041   
6021.589.961 8007 6002 1008 6002 3509 7002 60010 8002 85011 90045   
652187.861 9008 0002 2009 1002 45010 3002 75011 4003 00012 60049   
7020.585.772 0008 4002 3009 6002 60010 8002 85012 0003 15013 20052.5
752083.682 1008 8002 40010 0002 70011 3003 00012 6003 30013 80056   
8019.581.592 2009 1002 50010 4002 80011 8003 15013 1003 45014 40060   

a Values of BMR/kg are presented for ease of calculation by those who wish to use different BMR factors.
b Calculated for each weight from the equations in Table 5 (rounded values).
c At 0.75 g per kg of protein with the quality and digestibility of milk or egg.


Table 45. Daily average energy requirement and safe level of protein intake for women aged 18–30 years
Weight
(kg)
BMR/kgaDaily energy requirementb according to BMR factor indicated:Safe level
of protein
intakec
(g/day)
(kcalth)(kJ)1.4 BMR1.6 BMR1.8 BMR2.0 BMR2.2 BMR
(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)
4027112.91 5006 3001 7007 2001 9508 1002 1509 0002 3509 90030   
4525.5106.61 6006 7001 8507 7002 1008 6002 3009 6002 55010 60034   
5024.5102.51 7007 2001 9508 2002 2009 2002 45010 2002 70011 30037.5
5523.598.321 8507 6002 1008 6002 3509 7002 60010 8002 85011 90041   
602396.231 9508 1002 2009 2002 50010 4002 75011 5003 05012 70045   
6522.594.142 0508 6002 3009 8002 60011 0002 90012 2003 20013 50049   
702292.052 1509 0002 45010 3002 75011 6003 05012 9003 35014 20052.5
7521.589.962 2509 4002 55010 8002 90012 1003 20013 5003 50014 80056   

a Values of BMR/kg are presented for ease of calculation by those who wish to use different BMR factors.
b Calculated for each weight from the equations in Table 5 (rounded values).
c At 0.75 g per kg of protein with the quality and digestibility of milk or egg.


Table 46. Daily average energy requirement and safe level of protein intake for women aged 30–60 years
Weight
(kg)
BMR/kgaDaily energy requirementb according to BMR factor indicated:Safe level
of protein
intakec
(g/day)
(kcalth)(kJ)1.4 BMR1.6 BMR1.8 BMR2.0 BMR2.2 BMR
(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)
4029.5123.41 6506 9001 9007 9002 1508 9002 3509 9002 60010 90030   
4527.5115.11 7007 3001 9508 3002 2009 3002 45010 4002 70011 40034   
5025.5106.61 8007 5002 0508 5002 3009 6002 55010 7002 80011 70037.5
5524100.41 8507 7002 1008 8002 3509 9002 65011 0002 90012 10041   
6022.594.141 9007 9002 2009 0002 45010 2002 75011 3003 00012 40045   
6521.589.961 9508 2002 2509 4002 55010 5002 80011 7003 10012 90049   
7020.585.772 0508 4002 3009 6002 60010 8002 90012 0003 20013 20052.5
752083.682 1008 8002 40010 0002 70011 3003 00012 6003 30013 80056   

a Values of BMR/kg are presented for ease of calculation by those who wish to use different BMR factors.
b Calculated for each weight from the equations in Table 5 (rounded values).
c At 0.75 g per kg of protein with the quality and digestibility of milk or egg.


Table 47. Daily average energy requirement and safe level of protein intake for women over the age of 60 years
Weight
(kg)
BMR/kgaDaily energy requirementb according to BMR factor indicated:Safe level
of protein
intakec
(g/day)
(kcalth)(kJ)1.4 BMR1.6 BMR1.8 BMR2.0 BMR2.2 BMR
(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)(kcalth)(kJ)
4025.5106.61 4006 0001 6506 8001 8507 7002 0508 5002 2509 40030   
4523.598.321 5006 2001 7007 1001 9008 0002 1508 8002 3509 70034   
5022.594.141 5506 6001 8007 5002 0008 5002 2509 4002 45010 40037.5
5521.589.961 6506 9001 9007 9002 1008 9002 3509 9002 60010 90041   
6020.585.771 7007 2001 9508 2002 2009 3002 45010 3002 70011 30045   
6519.581.591 8007 4002 0508 5002 3009 5002 55010 6002 80011 70049   
701979.491 8507 8002 1508 9002 40010 0002 65011 1002 95012 20052.5
7518.577.401 9508 1002 2009 3002 50010 4002 75011 6003 05012 80056   

a Values of BMR/kg are presented for ease of calculation by those who wish to use different BMR factors.
b Calculated for each weight from the equations in Table 5 (rounded values).
c At 0.75 g per kg of protein with the quality and digestibility of milk or egg.

Table 48. Daily average energy requirement and safe level of protein intake for adolescents aged 10–18 years
AgeMedian weightMedian heightBMR/kgaDaily energy requirementbSafe level of protein
intakec
(years)(kg)(cm)
 (kcalth)(kJ)(BMR factor)(kcalth)(kJ)(g/kg)(g/day)
Boys         
10–1234.514436.5152.71.752 2009 2001.0   34
12–1444   15732.5135.91.682 40010 0001.0   43
14–1655.516829.5123.41.642 65011 1000.9552
16–1864   17627.51151.602 85011 9000.9  56
Girls         
10–1236   145331381.641 9508 2001    36
12–1446.515728.5119.21.592 1008 8000.9544
14–1652   16126.5110.81.552 1509 0000.9  46
16–1854   16325.5106.61.532 1509 0000.8  42

a, b, c See notes to Tables 42–47

Table 49. Daily average energy requirements and safe level of protein intake for infants and children aged 3 months to 10 years (sexes combined up to 5 years)
AgeMedian
weighta
Energy requirementSafe level of
proteinc intake
(kg)(kcalth/kg)b(kJ/kg)b(kcalth/day)(kJ/day)
  (g/kg)d(g/day)e
Months:
3–67   1004187002 3001.8513  
6–98.5   953978103 4001.6514  
9–129.51004189504 0001.5014  
Years:
1–211   1054391 1504 8001.2013.5
2–313.51004181 3505 7001.1515.5
3–516.5   953971 5506 5001.1017.5
  BoysGirlsBoysGirls  
5–720.590377853561 8507 7001 7507 3001.0021  
7–1027   78326672802 1008 8001 8007 5001.0027  

a From NCHS, average of boys and girls at mid-point of age range.
b From Table 21 up to 1 year; from Table 23 for 1–10 years.
c In terms of protein with the digestibility and quality of milk or egg.
d From Table 33, rounded to nearest 0.05 g.
e Rounded to nearest 0.5 g.

8.3.2 Protein

The derivation of the safe level of protein intake is shown in Table 34. No adjustment is at present recommended for protein quality, other than for digestibility (section 7.3.3).

8.4 Infants and children

It is recommended that the calculation of both energy and protein requirements for this age group should be made in two steps: first, the requirement per kg should be obtained, according to the age range; secondly, this should be multiplied either by the actual weight, or by the median weight for age, to obtain the total requirement (Table 49).

Rather narrow age ranges are given up to 3 years because until this age the requirement per kg for protein changes rapidly. Thereafter, the energy requirement per kg changes relatively more than the protein requirement.

The body weights shown in the table are presented as a guideline, to be used when actual weights are not known. Within each age range there may be an almost 2-fold variation in acceptable body weight. For more detailed calculation of the requirements of children, if actual weights are not available, the user should obtain the median weight at the actual age from the NCHS tables.

Adjustments for protein quality, according to age, should be made as set out in Table 40.

8.5 Pregnancy and lactation

The extra energy and protein requirements for pregnancy and lactation are shown in Table 50.

Table 50. Average extra requirements for energy and protein during pregnancy and lactation
 EnergyProtein
(kcalth/day)(kJ/day)(g)
Pregnancy   
full activity2851 2006
reduced activity200   8506
Lactation   
first 6 months5002 10017.5
after 6 months5002 10013   

Although during pregnancy the requirements increase from the first to the third trimester, the pregnant woman is able to store energy and perhaps protein during the early stages for use later (see section 6.2.1.2). Therefore only a single figure is given for the extra amounts needed per day throughout pregnancy.

In lactation it is assumed that part of the extra energy requirement for milk production during the first 6 months is derived from fat stores laid down during pregnancy (section 6.2.2). It is accepted that, for the protection of the infant, breast-feeding should be continued for longer when possible. However, there is no implication that the extra requirements proposed in Table 50 for lactation from 6–24 months will enable the mother to produce enough breast milk to satisfy the infant's energy and protein requirements.

Table 51. Corrections for digestibility and quality of the diet when intakes are being matched with requirements
A. The method recommended for general use is to correct the diet
Corrections for available energy
The apparent energy content of the diet is obtained by using the Atwater factors:
 Protein4 kcalth (17 kJ) per g
 Carbohydrate4 kcalth (17 kJ) per g
 Fat9 kcalth (38 kJ) per g
For diets containing low amounts of fibre:
available energy = calculated energy × 1.0
For diets containing moderate amounts of fibre:
available energy = calculated energy content × 0.975
For diets containing large amounts of fibre (e.g., all vegetable):
available energy = calculated energy content × 0.95
Correction of dietary protein for digestibility and quality
The total protein content of the diet = total N × 6.25
The biological value of the diet = total protein × digestibility factor × amino acid score
 • the digestibility factor being the digestibility relative to that of the reference protein (egg or milk), expressed as a percentage; (see Table 36)
 • the amino acid score as expressing the amino acid pattern as a percentage of the appropriate reference pattern for each age group (see Table 40)
These corrected intakes are then compared with the requirements shown in the previous tables.
B. The alternative method is to correct the requirement
The “standard” requirements are those given in the preceding tables.
Energy. The apparent energy content of the diet is obtained by applying the Atwater factors (as under A)
When diets contain low amounts of fibre:
 corrected requirement = standard requirement × 1.0
When diets contain moderate amounts of fibre:
 corrected requirement = standard requirement × 1.025
When diets contain high amounts of fibre:
 corrected requirement = standard requirement × 1.05
Protein. The total protein content of the diet = N × 6.25
The corrected requirement in terms of the diet consumed is:
 
The amino acid score is that appropriate for each age group.
The corrected requirements are then compared with observed intakes.

8.6 Corrections for the quality of the diet

Table 51 shows the method of applying corrections for the composition of the diet so that the available energy can be matched with the average energy requirement while the utilizable protein can be matched with the safe levels of protein intake given in the tables. The method proposed is the converse of that recommended in the report of the 1971 Committee (1), in which the corrections were applied to the estimates of requirements.

REFERENCES

  1. FAO Nutrition Meetings Report Series, No. 52; WHO Technical Report Series, No. 522, 1973 (Energy and protein requirements:) report of a Joint FAO/WHO Ad Hoc Expert Committee).

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