Breastfeeding Calorie Calculator

In order to produce breast milk energy is required and the body burns calories doing so. This calculator adds this amount on top of your already daily calorie burn and shows you how much food you need in order to maintain yourself and your milk production.

Please enter your age, height, weight and daily activity level. Then indicate what stage of breastfeeding you are at or how much breast milk you actually pump out so the calculator can work out how many calories you need to maintain your weight as well as a slow rate of weight loss.

Simple answer:

For most mothers the energy expenditure of breastfeeding up to six months is about 500kcal per day. After six months when complementary feeding becomes more important this falls to around 400kcal per day.

Health guidelines generally give lower values of about 330 to 400 kcal. This difference is intentional. The guidelines assume that you will get about 170 kcal per day from the fat stores built up during pregnancy, so all you need to eat is the difference.

This assumption is built into this tool as the natural weight women tend to return to after giving birth. If you select that goal, then the recommended calorie intake matches what's in the well-known guidelines. When you choose "maintain weight," you're asked to eat a full 500 kcal.

How does the calculator work?

The daily calorie requirement estimate is made up of three layers and the calculator shows each layer separately so there are no hidden items.

Layer 1: basic turnover

The Mifflin-St Jeor Formula estimates the calories burned at rest. It is one of the most commonly used formulas by nutritionists and here we are using the formula for women.

Here w is body weight in kilograms, h is height in centimeters and a is age in years. The basal metabolism of a person aged 30 with a weight of 68 kg and a height of 165 cm is about 1,400 kcal per day.

Layer 2: Activity level

Your resting metabolism is only part of the day. When you multiply your resting metabolism by an activity factor, you get your total daily energy expenditure or calories expended in a normal day.

Be honest here and remember that carrying a baby, pushing a stroller or getting up several times at night to settle a baby are all activities. Even with the same resting metabolism of 1400 calories, moderate activity can add about 2170 calories per day.

The energy of breast milk on the 3rd shift.

The last layer represents the energy lost through breast milk production. When this is added to the total requirements it gives the amount of calories needed to maintain weight while producing enough milk.

Where do the numbers 330, 400 and 500 come from?

These numbers are not made up; they're based on dietary guidelines and have been calculated from measured breast milk volumes and the energy density of breast milk.

Babies under six months old drink an average of about 780 ml of breast milk a day. Mature milk contains around 0.67 kcal per millilitre, so the daily energy intake from breast milk is around 500 kcal.

At the age of six to twelve months, daily intake falls to about 600 ml as complementary foods are added and energy supply from breast milk reduces to around 400 kcal. Subtracting the recommended 170 kcal that should be covered by fat reserves gives a value of +330.

Some of these values are not published constants but estimates based on proportional calculations, because there is a wide variation in the amount of infant formula or complementary food that babies receive from families. In mixed feeding you should use the results as a starting point and adjust them according to your weight.

Breast milk volume measurement method for nursing mothers.

If you're pumping and know your milk volume, then you can skip the step-by-step estimates altogether. Change the method to "Daily actual breastmilk volume" and enter the total amount of milk that you've pumped in a 24 hour period.

The calculator multiplies this value by the energy density of 0.67 kcal per millilitre. This is the basis for the guidelines given. As the result is based on your actual breast milk volume and not an average amount for babies, it best fits your individual situation.

This constant is stated in the materials as the energy content of breast milk being between 65 and 70 kcal per 100ml. This tool uses 0.67kcal per milliliter. This is the value that justifies the official step values of 500kcal and 400kcal to ensure both methods are consistent.

Does pumping and breastfeeding burn the same amount of calories?

Yes. The calorie expenditure factor is the breast milk itself, not how it's delivered. So mothers who pump out 780 mL a day and those who deliver that same amount directly will expend the same amount of energy.

That's why this method is suitable for everyone including those who fully pump, use mixed feeding or have wondered if pumping counts - it does!

Breastfeeding twins or triplets

As milk production increases to meet demand, the amount of breastmilk doubles for two babies and so does the energy cost approximately. For mothers who exclusively breastfeed their twins until six months of age, the energy expenditure through breastfeeding is about 1,000kcal per day.

There are records of healthy women who breastfeed multiples producing two to three liters of milk per day. This is an astonishing metabolic load. If you're breastfeeding multiple babies, the numbers double in stages when choosing twins or triplets. It's advisable to discuss this directly with a nutritionist to ensure intake.

Breastfeeding during pregnancy

It is common for women to breastfeed while pregnant and in this case the two requirements add up rather than cancel each other out. The calculator takes into account the additional requirement during pregnancy when calculating energy needs for breast milk, as stated in the "Nutrition Recommendations".

If you select "Pregnant" the weight loss goals are completely ignored. It is not recommended to intentionally reduce calories while pregnant. Especially if you're producing breast milk, consult a midwife or doctor and do not rely on this calculator.

Safe weight loss while breastfeeding

It is possible to lose weight while breastfeeding but it should not be done too quickly. Severely restricting your food intake is the surest way to reduce milk production.

One kilogram of body fat stores about 7,700 calories. If you reduce your daily intake by a constant 500 calories per day, then mathematically speaking, you will lose approximately one pound per week, which is the fastest rate this tool offers.

Regardless of the speed you choose, the calculator will ensure that your goal never falls below 1800 calories per day while breastfeeding. If the calorie deficit you select is already below this limit, the system will reduce the deficit and notify you.

This minimum is not arbitrary; the breastfeeding guidelines repeatedly state that a daily intake of 1500 to 1800 kcal is considered as being in the range where milk production and energy levels can be affected. The higher figure is used as the safer limit for reduction.

Example calculation:

We take a woman aged 30 with a height of 165 cm and weight of 68 kg who exclusively breastfeeds her four-month-old baby and has moderate activity level.

Their basic metabolic rate is 10 x 68 + 6.25 x 165 - 5 x 30 - 161 which equals 1400 kcal per day. Multiplied by the moderate activity factor of 1.55, this gives a calorie requirement for weight maintenance (not taking into account milk production) of 2170 kcal.

If you take into account the energy from breast milk (500kcal), to maintain your weight you need 2670 kcal per day. If you opt for a natural weight loss of 170kcal, then there are 2500 kcal left daily. This corresponds with the guidelines we have established in another way and represents a value of +330.

Protein, fluids and other foods

Calories are only half the story. Breastfeeding increases daily protein requirements to about 1.1 grams per kilogram of body weight, which is roughly 70-90 grams for most mothers.

Hydration is also very important. The recommended daily fluid intake for nursing women is about 3.8 liters. About four-fifths of this comes from drinks and the rest from food. It's a good habit to drink a glass of water with each nursing meal.

The nutrient ratios shown in the calculator set a fat ratio of thirty percent of calories, calculates protein needs based on body weight and divides the rest between carbohydrates. This is a sensible default setting rather than a fixed prescription, so you can make flexible adjustments within this range.

There are two nutrients that breastfeeding women should pay particular attention to: iodine (about 290 micrograms daily) and choline (about 550 milligrams daily). Both can be obtained from dairy products, eggs, and seafood. Vegetarian or vegan mothers should also check their intake of vitamin B12 and iron.

What happens when you eat too little?

The first sign most mothers notice is not a decrease in milk production but rather feeling worse themselves. Fatigue, dizziness, mood swings and hair loss often occur before the milk supply changes.

The milk volume is usually maintained temporarily as the body attempts to protect its lactation function. If the milk volume decreases it often happens suddenly and not gradually so it's important to maintain a lower limit.

In the newborn period skipping meals especially when you don't have time to eat can be a big problem. It is more helpful to have a small hand-held snack next to your nursing chair than any type of supplement to solve problems with milk production.

How accurate are these figures?

All the figures mentioned here are estimates. The error rate of the formulas used is about ten percent and milk volume varies greatly from mother to mother. In addition, the body's ability to mobilize fat reserves differs from person to person.

Use these numbers as a starting point and adjust them as you notice changes in your body. If you're losing more than one pound per week or if your milk supply is decreasing, eat a little more. If you continue to be in a calorie deficit but don't see any change in weight after about a month, slightly reduce your intake.

It is more helpful to track your weight over three or four weeks than it is to use any formula on this page.

This calculator is for general educational purposes only and does not constitute medical or nutritional advice. As energy requirements vary widely during breastfeeding, the estimates provided here are no substitute for an assessment by a qualified professional. Consult your doctor, midwife, lactation consultant or nutritionist before making any major changes to your intake. This is especially important if you have health problems, had a complicated birth, or have concerns about milk production or your baby's weight gain.