Breastfeeding Calorie Calculator

What breastfeeding costs your body

Making breast milk is work, and your body bills you for it in calories. Around 500 calories a day go into feeding a baby who is taking nothing else, and roughly a fifth of the energy in your own meals ends up in the milk. That is why the advice is not to eat less while you nurse, but to eat a little more of the right things.

The number is smaller than most new mothers expect, and smaller than older advice used to say. It is a few hundred calories, not a second dinner. An extra snack and a slightly bigger lunch usually cover it.

What matters is that the extra comes from somewhere. Your body will pull it from fat laid down during pregnancy if it has to, which is fine in moderation and is part of how gradual postpartum weight loss works. Pull too hard and you can end up tired, short of nutrients, and in some cases short of milk. This calculator gives you the daily figure to aim at so you do not have to guess.

How many extra calories a day

Two federal bodies publish numbers, and they differ because they answer slightly different questions.

The Centers for Disease Control and Prevention says an extra 330 to 400 kilocalories a day is the right amount for a well nourished breastfeeding mother, measured against what she ate before pregnancy. That range assumes gentle postpartum weight loss, and the CDC notes the figure moves with age, body mass index, activity level and how much of the feeding is breast milk. The Office on Women's Health says the same thing in plain words on its eating healthy while breastfeeding page: 330 to 400 more calories a day than before pregnancy.

The National Institute of Child Health and Human Development gives a higher figure. Its breastfeeding and calories page puts the increased need at about 450 to 500 calories a day, and says women who are not trying to lose weight after pregnancy should add that much. The gap between the two is deliberate: the lower number lets a little weight come off, the higher one holds you steady.

The CDC page is the one to read on the details at maternal diet and breastfeeding, including the note that the number also depends on whether you are exclusively breastfeeding or combining breast milk with formula.

Exclusive, mostly or partly breastfeeding

A mother feeding a baby nothing but breast milk is paying the full cost. A mother whose baby takes half formula is paying about half. The calculator scales the full figure by how much of the milk supply you are providing.

These shares are an estimate for planning. Milk supply follows demand, so a baby who takes more breast milk asks your body for more. If you are dropping formula feeds and nursing more, move up a row. If you are weaning, move down.

Pumping counts the same as nursing. A mother who pumps at work is still making the milk, so the extra calories still apply on those days.

The floor you should not go under

There is a bottom line, and it is higher than the number most diet culture gives for weight loss. Breastfeeding is not the time to run a hard calorie deficit.

The Office on Women's Health puts adult women at between 1,600 and 2,400 calories a day depending on age, size and activity. Adding the 330 to 400 calories of breastfeeding cost on top of the low end lands near 1,900 to 2,000, which is why this calculator flags anything under 1,800 as too low for most nursing mothers. Below that it becomes hard to get the protein, calcium, iodine and choline you and your baby both need.

The field on the calculator defaults to 1,800 and you can raise it. If your doctor or a dietitian has given you a different number, use theirs. Some mothers with a smaller frame, a physically demanding job or a history of disordered eating need a higher floor, and some need a lower one under supervision.

Watch for the signs that you are under eating rather than counting to the last calorie. Feeling cold all the time, losing more than about a pound a week after the first few weeks, feeling flat and tired, or noticing your supply drop are all reasons to add food rather than take it away.

Worked example: 4 months, exclusively breastfeeding

Take a mother four months into exclusive breastfeeding who ate about 2,000 calories a day before she was pregnant and wants the pregnancy weight to come off slowly.

• Stage: the baby is under 6 months, so the CDC figure is 330 calories a day
• Feeding: exclusive, so the full 100 percent applies, and the figure stays at 330
• Daily target: 2,000 + 330 = 2,330 calories a day
• Over a week: 330 x 7 = 2,310 calories a week
• Over a 30 day month: 330 x 30 = 9,900 calories

Now change two things. At eight months, mostly breastfeeding with some formula, and holding her weight steady, the NIH figure of 500 applies at 75 percent, which is 375 calories a day. On a 2,200 base that gives a target of 2,575 calories.

And at 12 months, still exclusively breastfeeding and still losing slowly, the CDC figure moves up to 400, giving a 2,400 calorie target on the same 2,000 base. Three answers from one calculator, all from changing the stage, the feeding pattern and the goal.

Where those extra calories should come from

Where the extra comes from matters as much as how much it is. A few hundred calories of soda and cookies will hit the number and miss the point, because nursing raises your need for protein, calcium, iodine, choline and several vitamins at the same time.

Food first is the rule the CDC and the Office on Women's Health both give, with supplements only where a professional recommends them. In practice the extra fits into one added snack and one slightly larger meal:

• A substantial snack. Oatmeal with milk and fruit, yoghurt with granola, or peanut butter on wholegrain toast lands in the 300 to 400 calorie range.
• A bigger main meal. An extra portion of beans, eggs, fish or chicken plus a little more rice or bread.
• Protein at every meal. Eggs, dairy, beans, lentils, lean meat and fish low in mercury.
• Calcium every day. Dairy, fortified alternatives, leafy greens and canned fish with bones.

The CDC also notes that the recommended intake of iodine and choline rises during lactation, to 290 micrograms of iodine and 550 milligrams of choline a day, and that diet alone may not cover it, which is why many nursing mothers are advised to keep taking a prenatal or a multivitamin until they wean. Ask your doctor which one.

Fluids, protein and the rest of the plate

Calories are only one line on the list. Two others come up constantly in the breastfeeding guidance.

Thirst is not a reliable guide while you are nursing, so the glass of water with every feed habit does more good than waiting until you feel dry. Skip the sugary drinks and the sports drinks, which add calories without the nutrients.

When to call your doctor or a lactation consultant

This calculator is a starting point, and several situations are worth a conversation with someone who can see the whole picture.

• Your supply is dropping. Under eating is one cause among many, and a lactation consultant can tell you which one you are dealing with.
• You are losing weight fast without trying. More than about a pound a week after the first month or so is worth raising with your doctor.
• You are nursing two babies or nursing while pregnant. Both push the calorie need well past the single baby figures here.
• You have a health condition that affects diet, such as diabetes, thyroid disease or a history of an eating disorder.
• Your baby was premature or has feeding problems, which changes both the supply question and the nutrition question.
• You are thinking about a restrictive diet. Do it with a registered dietitian, not on your own.

Every one of the figures on this page is an average across a lot of people. Your own number sits somewhere near it, and your own body will tell you where. Hungrier than usual is a normal signal while you are breastfeeding.

This is an estimate for planning and not medical advice. The ranges come from the CDC, the Office on Women's Health and the National Institute of Child Health and Human Development, and individual needs vary with age, size, activity and how much milk you are making. Talk to your doctor, a lactation consultant or a registered dietitian before you change what you eat.