Table 7.

Metabolizable energy content of breast milk¹.

Study	Colostrum 1–5 days (kcal/100 mL)	Transition 6–14 days (kcal/100 mL)	Mature >14 days*    (kcal/100 mL)	Method	N	Population
[19]			72.7 ± 13.8	Calculated	13	USA
[20]	45.1 ± 16.5	56.5 ± 10.2		Calculated	10	Canada
[57]			63.4 ± 1.0**	Calculated	37	USA
[59]			63.2 ± 1.8**	Bomb calorimetry	10	USA
[22]	64.9 ± 4.4		74.9 ± 2.5	Calculated	10,29	Venezuela
[24]			78.2 ± 3.5	Calculated	13	USA
[25]			63.7 ± 2.6**	Bomb calorimetry	12	USA
[77]			67.1±1.7	Bomb calorimetry	10	USA
[26]	48.9 ± 9.2	65.1 ± 16.2	69.5±18.7	Calculated	10,12,12	USA
[27]	54.8 ± 0.5		61.6 ± 0.9**	Bomb calorimetry	227	Japan
[78]			61.9 ± 7.4**	Bomb calorimetry	11	Canada
[79]			61.3 ± 17.7**	Doubly labeled water	12	UK
[30]	54.9 ± 16.5		63.5 ± 16.5**	Calculated	65,63	Peru
[31]			64.0 ± 7.4**	Calculated	18	Australia
[32]	46.4 ± 1.5	47.3 ± 1.9	50.4 ± 2.0**	Calculated	41,41,41	India
[80]			68.5 ± 3.8	Calculated	25	USA
[34]		65.8 ± 1.8	67.8 ± 1.8	Calculated	48,46	Finland
[35]			67.6 ± 3.1	Calculated	41	North China
[36]	58.1 ± 13.2	60.1 ± 5.1	60.0 ± 6.7**	Calculated	3,5, 5	Netherlands
[81]			65.0 ± 0.5**	Calculated	415 (milk bank donors)	USA
[72]			65.4 ± 2.2**	Bomb calorimetry	8	USA
[38]	53.9 ± 2.8	56.8 ± 2.2	65.9 ± 2.6**	Calculated	21,39,40	Japan
Meta-analysis results	53.6 ± 2.5	57.7 ± 4.2	65.2 ± 1.1

Reported as mean ± SEM.

¹Gross energy content of breast milk was converted into metabolizable energy (ME) levels by multiplying the classic Atwater factors 4, 4, 9 kcal/g for carbohydrate, protein, and lipid, respectively, and by assuming 93% of gross breast milk energy reported by bomb calorimetry methods is metabolizable.

*Mature milk > 14 days and <6 weeks.

** Indicates value below current infant formula level 67.0 kcal/100 mL.