A recent publication from the New York State Department of Health contained a single bullet point that has attracted some attention in the last month on the internet. On page 2 of the leaflet, the second point under their section about benefits for mothers is that breastfeeding “burns about 500 calories a day, so you lose the weight you gained more easily”.
Calculating the energy needs for breastfeeding can be done rather simply. Mature milk is generally regarded to have an energy content of 67 kcal/100ml, and exclusively breastfeeding women produce about 700 – 900 ml milk per day, so doing the sums ends up at 469 – 603 kcal. It is good to keep in mind that producing milk isn’t 100% efficient, so that means that more energy than this is needed to produce the milk. A textbook I have (Human Nutrition, Geissler and Powers, 11th Ed., page 315) estimates the efficiency to be around 94%, so this would increase the energy needs for the production of milk to be 500 – 640 kcal per day.
So the estimate from the NYC DOH seems to be a little on the low side, however pregnancy weight gain guidelines normally err on the side of caution and include around 3kg extra fat retained at birth. The recommendations allow for a gradual reduction in this extra fat during the breastfeeding period. Some scientists have also found that lactating women have a reduced metabolic rate compared to before they were pregnant, due to a reduction in muscle mass during pregnancy.
A useful tool for calculating energy needs during breastfeeding is at the US Department of Agriculture’s MyPyramid website. It lets you get an estimate of how many calories you need to eat in a day, and includes a basic diet plan as well. I just punched in my values, and they recommend 2400 kcal in the first six months, and 2600 up to one year if I continue, which is about 500 kcal more than what I normally eat. So this could be a way for me to lose any extra baby pounds I may have picked up during my pregnancy.
What have your experiences been when eating for two? Are the guidelines realistic?