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 equivalents^a (mg)	Total folate (μg)	Ascorbic acid (mg)	Vitamin A retinol equivalents^b (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