Answer to Question 1
It depends on whether the mother is exclusively breastfeeding or feeding a combination of human milk and formula. If breastfeeding only, she will need 500 kcal extra per day (minus 170 kcal available from fat stores = 330 kcal) for the first 6 months and 400 kcal/day for the second 6 months. Recommendations for micronutrients are similar to those during pregnancy, although vitamin A requirements during lactation are greater and folate requirements are a bit reduced. Vitamin C is of interest because large amounts of vitamin C are secreted in milk and thus the RDA increases to 120 mg/day during lactation. Inadequate fluid intake can decrease milk volume; thus, fluid needs for lactating women are 13 cups per day.
Answer to Question 2
The best indicators of adequate milk production are infant weight gain and frequency of wet diapers. Parents should expect 4-5 heavy diaper changes per day. Often during the first six months, infants have very small stomachs and can only consume small amounts of milk at each feeding, so moms may be breastfeeding as often as every two to three hours. Infants should be allowed to nurse on demand. It is expected that newborns will nurse at least 8-12 times each day.
The Calvin Cycle Was Determined by Isotope Labelling Methods
Energy flow through an ecosystem.
Energy budget for a temperate deciduous forest (data from Gosz et al. 1978).
Basic Types of Energy
Free Energy
Geothermal energy and powers Earth’s systems