I just found this breastfeeding calorie calculator on the web that gives you a rough estimate of how many calories you need to maintain your current weight while breastfeeding. This calculation is based on your height, weight, and (if you know it) your body fat percentage.
I punched in 136 lbs, my height of 5′ 7″, exercising 5 times a week (normal), and my approximate body fat percentage of 21% (using the Omron HBF-306C, taking the average of 3 days of measurements at the same time of day), and found that my daily maintenance calories would be 2216.
That seems low. When I track my daily caloric intake when I’m not trying to restrict calories — i.e. when I’m just eating to my appetite — my average for each day is 2400 to 2600 calories. This intake has actually produced a tiny but steady weight loss of about 4 ounces per week.
Ah, and indeed it is low. Reading down into the page:
The calculator will calculate Basal Metabolic Rate (based on the above factors) – then add in the net amount of Calories required to support lactation. It is a net amount as it presumes that some of the energy requirements will be met using fat tissue stores. Therefore, gradual weight loss should occur (see more below).
Further down, referencing an article called “Energy Requirements During Pregnancy and Lactation” from the Public Health Nutrition journal (2007):
For exclusive breastfeeding through 5 months postpartum, the energy cost of lactation (based on mean milk production) is 454 Calories per day (over non-pregnant, non-lactating women). This amount takes into account the energy released from tissue stores.
Ah hah. So, this calorie calculator is actually giving us the lowest number of calories that we as breastfeeding women should be consuming in order to preserve lactation but lose weight at the same time. They’re essentially telling us to consume the baseline amount (for me, 2216) and to use the average of 454 calories per day used to produce milk as the negative calorie balance that produces weight loss.
Still, I would recommend using the calculator only “for entertainment purposes”.
Use a diet journal as the first and best method of determining how many calories you are currently taking in. Combining this with tracking your weight for the duration of your journaling — say 2 weeks — will give you a very clear picture of how much your daily calorie intake ought to be adjusted.
If you’re interested in reading more, check out my earlier article, “How Many Calories Does Breastfeeding Burn?”