This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.
Why breastfeeding raises energy needs
Making breast milk takes energy. A baby who is fed only breast milk drinks on average about 780 mL a day in the first six months, which contains about 500 kcal. Part of that energy comes from the fat stored during pregnancy, so the extra food needed is a little lower than the energy in the milk.
How the calculator estimates your needs
- Resting metabolism with the Mifflin-St Jeor equation for women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
- Daily needs without breastfeeding: resting metabolism × an activity factor, from 1.2 (sedentary) to 1.725 (very active)
- Extra calories for breastfeeding, from the US Institute of Medicine dietary reference intakes:
| Baby’s age | Extra calories, exclusive breastfeeding |
|---|---|
| 0 to 6 months | about 330 kcal a day (500 kcal in milk, minus 170 kcal from fat stores) |
| 7 to 12 months | about 400 kcal a day |
For partial breastfeeding, the calculator uses half of these amounts.
Example
A 31-year-old woman, 5 ft 4 in (164 cm) tall and weighing 150 lb, who is lightly active and breastfeeds a 3-month-old exclusively, needs about 1,900 kcal a day before breastfeeding and about 2,230 kcal including it.
Losing weight while breastfeeding
Gradual weight loss of about 1 to 2 pounds a month is common and safe. Most advice is not to eat less than about 1,800 kcal a day, and to avoid crash diets, which can reduce milk supply in some women.
Eating well
- Drink to thirst; many nursing mothers need about 13 cups of fluid a day.
- Keep eating a varied diet with protein, whole grains, fruit, vegetables and dairy or calcium-rich foods.
- Continue a prenatal vitamin or follow your provider’s advice, especially about vitamin D, iodine and choline.
- Limit caffeine to about 300 mg a day, and avoid alcohol or time it well away from feeds.
- If you follow a vegan diet, take vitamin B12.