Nutrition and energy

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Nutrition and energy

Table 6.1 Normal body compositon (of a 70 kg man)

Constituent

kg

water

42

 intracellular

28

 extracellular

14

solids

 fat

12.6

 protein

11.2

 intracellular (muscle)

8.4

 extracellular (collagen)

2.8

minerals

3.8

carbohydrate

0.4

Table 6.2 Daily requirements for energy

Age

Energy

kcal/kg

kJ/kg

infant

3 months

120

500

child

4–6 years

90

380

adolescent

 male

13–25 years

57

240

 female

13–25 years

50

210

adult

 male

46

190

 female

40

170

Table 6.3 Energy expenditure of a normal adult

Time

kcal

kJ

Total range kcal (kJ)

male

 bed

8 h

500

2100

 non-occupational activities

8 h

700–1500

3000–6300

 work

8 h

  light

1100

4600

2300–3100

 (9660–13 000)

  very heavy

2400

10 100

3600–4400

 (15 100–18 500)

female

 bed

8 h

420

1760

 non-occupational activities

8 h

580–980

2430–4120

 work

8 h

  light

800

3360

1800–2200

 (7560–9240)

  heavy

1400

5880

2400–2700

 (10 100–11 340)

Table 6.4 Macronutrient stores in relation to daily intake

Macronutrient

Total amount in body

Energy equivalent

Days' supply if the only energy source

Daily intake g

% of store

Carbohydrate

0.6 kg

8.5 MJ

<1

300

60

 free glucose

12 g

 liver glycogen

100 g

 muscle glycogen

500 g

Fat (triacylglycerol)

12–18 kg

550 MJ

56

100

0.7

 circulating in plasma

5 g

 stored in adipocytes

12–18 kg

Protein and amino acids

12 kg

200 MJ

100

0.8

 free amino acids

100 g

 protein

12 kg

Table 6.5 Recommended daily amounts of some nutrients for population groups

Age range (years)

Occupational category

Thiamin (mg)

Riboflavin (mg)

Nicotinic acid equivalentsa (mg)

Total folate (μg)

Ascorbic acid (mg)

Vitamin A retinol equivalentsb (μg)

Vitamin D cholecalciferol (μg)

Calcium (mg)

Iron (mg)

Notes

a 1 nicotinic acid equivalent = 1 mg available nicotinic acid or 60 mg tryptophan.

b 1 retinol equivalent = 1 μg retinol of 6 μg β-carotene or 12 μg other biologically active carotenoids.

† No dietary sources may be necessary for children and adults who are sufficiently exposed to sunlight but during the winter children and adolescents should receive 10 μg (400 i.u.) daily by supplementation.

‡ This intake may not be sufficient for 10% of girls and women with large menstrual losses.

* For the third trimester only.

boys

under 1

0.3

0.4

5

50

20

450

7.5

600

6

1

0.5

0.6

7

100

20

300

10

600

7

2

0.6

0.7

8

100

20

300

10

600

7

3–4

0.6

0.8

9

100

20

300

10

600

8

5–6

0.7

0.9

10

200

20

300

600

10

7–8

0.8

1.0

11

200

20

400

600

10

9–11

0.9

1.2

14

200

25

575

700

12

12–14

1.1

1.4

16

300

25

725

700

12

15–17

1.2

1.7

19

300

30

750

600

12

girls

under 1

0.3

0.4

5

50

20

450

7.5

600

6

1

0.4

0.6

7

100

20

300

10

600

7

2

0.5

0.7

8

100

20

300

10

600

7

3–4

0.6

0.8

9

100

20

300

10

600

8

5–6

0.7

0.9

10

200

20

300

600

10

7–8

0.8

1.0

11

200

20

400

600

10

9–11

0.8

1.2

14

300

25

575

700

12‡

12–14

0.9

1.4

16

300

25

725

700

12‡

15–17

0.9

1.7

19

300

30

750

600

12‡

men

18–34

sedentary

1.0

1.6

18

300

30

750

500

10

moderately active

1.2

1.6

18

300

30

750

500

10

very active

1.3

1.6

18

300

30

750

500

10

35–64

sedentary

1.0

1.6

18

300

30

750

500

10

moderately active

1.1

1.6

18

300

30

750

500

10

very active

1.3

1.6

18

300

30

750

500

10

65+

sedentary

0.9–1.0

1.6

18

300

30

750

500

10

women

18–54

most occupations

0.9

1.3

15

300

30

750

500

12‡

55+

sedentary

0.7–0.8

1.3

15

300

30

750

500

10

pregnancy

1.0

1.6

18

500

60

750

10

1200*

13

lactation

1.1

1.8

21

400

60

1200

10

1200

15


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