Caloric Expenditure During Breastfeeding
Breastfeeding burns approximately 500 calories per day during the first six months of exclusive breastfeeding. 1
Energy Requirements and Expenditure
The energy cost of lactation is well-established across multiple authoritative guidelines:
The European Food Safety Authority (EFSA) specifies that exclusive breastfeeding during the first six months requires a mean energy expenditure of 670 kcal/day, based on average milk production of 807 g/day with an energy density of 0.67 kcal/g and 80% energetic efficiency. 1
After accounting for maternal fat stores mobilized during lactation (approximately 170 kcal/day), the net additional energy requirement is 500 kcal/day above pre-pregnancy needs. 1
A breastfeeding woman requires approximately 500 more kcal/day compared to a non-pregnant, non-lactating woman, with total milk volume averaging 780 mL/day (range 450-1200 mL/day) and energy content of 60-70 kcal/100 mL. 1
How Women Meet This Energy Demand
Lactating women achieve energy balance through multiple mechanisms:
Increased food intake accounts for the majority of energy needs (approximately 415-550 kcal/day when adjusted for body weight). 2
Mobilization of maternal fat stores contributes approximately 35-180 kcal/day, allowing breastfeeding mothers who use their nutrient stores to lose 0.5-1.0 kg/month after the first postpartum month. 1, 2
Some women reduce energy expenditure by approximately 180 kcal/day through decreased physical activity during the early postpartum period. 2, 3
Clinical Recommendations for Energy Intake
For women with diabetes or those requiring structured meal planning, an energy intake of 1,800 kcal/day typically meets nutritional requirements for lactation while allowing gradual weight loss of 1-2 pounds per month. 1
This represents an additional 200 calories above the pregnancy meal plan during the first 6 months of lactation. 1
Mothers should not receive less than 1,800 calories per day to maintain adequate milk production and maternal health. 4
Overweight women may safely lose up to 2 kg/month without affecting milk volume. 1
Important Clinical Considerations
The 500 kcal/day recommendation applies specifically to exclusive breastfeeding during the first six months; energy needs may differ with partial breastfeeding or after six months. 1
There is minimal evidence of metabolic adaptations (changes in basal metabolic rate or dietary-induced thermogenesis) during lactation, meaning women truly need this additional energy rather than becoming more efficient. 3
In moderately negative energy balance, women with adequate fat reserves can maintain lactation without adverse effects, as maternal stores contribute to meeting energy demands. 3
The satisfactory weight gain of the infant is the best indicator of adequate maternal caloric intake and milk production. 4