Nutrition, Exercise, and Weight Loss While Breastfeeding

Most mothers are highly motivated to eat a nutritious diet during their pregnancies. Assuming that you ate an adequate diet while you were pregnant, you can produce plenty of milk for your baby by keeping up this motivation and making sure that you continue your healthy eating patterns during lactation. While you should attempt to eat a "good diet" while you are nursing, you need to be aware that your diet doesn't have to be perfect in order to support lactation. You can still breastfeed even if your diet is less than ideal. You may be surprised to learn that studies have shown that maternal nutrition has only a minor effect on the composition and quantity of breastmilk produced. Usually, unless a mother is severely malnourished, her milk is fine. Mothers whose diets are poor deplete their own energy levels, and may become anemic, but their bodies will continue to produce the milk their baby needs by pulling from the mother's energy stores at her expense, but not her baby's. Most women in this country don't suffer from a lack of food, but rather from eating too much of the wrong kinds.

There are no special dietary rules to follow during lactation. If your eating habits are fairly healthy, there is no reason to change them while you are nursing. There are no special foods to avoid, or certain foods that you need to eat (like milk) in order to produce a plentiful supply of nutritious breastmilk. With rare exceptions, nursing mothers can eat pretty much anything they want to eat - including chocolate, broccoli, pizza, and diet soda - in moderation. Some dieticians and lactation experts feel that one advantage to breastfeeding may be that the milk is flavored by the foods the mother eats, so the baby becomes used to a variety of taste sensations, and tends to have fewer feeding problems as he gets older. One famous study showed that when mothers ate lots and lots of garlic, their milk tasted and smelled like garlic. Not only did the babies who drank the milk not have any digestive problems, but they actually preferred the garlicky milk over the unflavored milk. Think about it - women in South America who eat lots of peppers, or women in India who eat lots of curry don't have babies any more colicky or fussy than babies in the U.S. 
You've probably heard that eating "gassy" foods like cabbage, beans, or broccoli will make your baby gassy. I believe that this is one of many "old wive's tales", because gas is produced when bacteria in the intestine interact with the intestinal fiber. Neither gas nor fiber can pass into breastmilk, even when you have gas. 

Although it is possible for a baby to be sensitive to a food in his mother's diet, he is much more likely to react to a food given to him directly. I suspect that most mothers who swear that they can't eat (pizza, Mexican food, broccoli, cabbage, beans, chocolate, etc.) while they are nursing are actually overreacting to their baby's normal behavior on any given day. There is a natural tendency for every nursing mother to attribute every little thing her baby does to nursing. ALL babies have days when they are gassy, fussy, and spit up. Some babies have sensitive digestive systems, and no matter what you feed them, they will experience bouts of intestinal upsets. The one thing you can be sure of is that there is nothing you can put into a sensitive infant's stomach that will be easier to digest than breastmilk.

When you are nursing, you start to think "…he's so gassy today…must be something I ate…yep, I had pizza for dinner last night…that must be it. I can't eat pizza from now on." When taken to extremes, this sort of thinking can lead to a diet of nothing but boiled chicken and polished rice. 

In nearly 25 years of experience in working with nursing mothers I have seen very few cases of food sensitivity. I'm not saying it doesn't exist, just that it is highly uncommon. It is estimated that only 3-7% of babies will have any type of food sensitivity or allergy.  Signs of food sensitivity can include: inconsolable fussiness, suddenly waking in obvious distress, skin rashes, wheezing, and green mucousy stools. A strong family history of allergies (food or other) can also increase the possibility of food sensitivity. If you think your baby may be having problems with a food you have eaten, remember that it takes 4-6 hours after ingestion for a food to affects your breastmilk. Try eliminating the food you suspect from your diet for a minimum or 2-3 weeks. It may take a while for your baby to improve. Of course, during that time, he may outgrown his sensitivity anyway as his digestive system matures.

The one food that is the most common offender in causing problems with sensitivity and allergies is cow's milk. That's why it's the first food you should work on reducing or eliminating if you suspect your baby has a food sensitivity. It may take ten days to two weeks to eliminate cow's milk protein from your diet, so wait at least two weeks before you decide whether cow's milk is the problem. The problem with cow's milk is the protein, which is difficult for babies to digest, not with the lactose. Human beings are not born lactose intolerant, unless they are born with a rare metabolic disorder. Lactose intolerance is caused by a deficiency of the enzyme lactase, which breaks down lactose (milk sugar) so it can be easily digested. Mammals are born with this enzyme in their intestines. As they grow older and wean, the lactase enzyme decreases. That's why lactose intolerance rarely shows up in humans before age 3, since that's the average age of weaning (if that shocks you, check out the article on "Weaning".) Lactose intolerance is more common in Asian and African adults.

The proteins in cow's milk are primarily caseins, which are harder to digest than whey 
proteins, which are more prominent in human milk. The proteins in cow's milk pass into your milk, and can cause digestive problems for your baby. These proteins can even sensitize your baby before birth if you drink lots of milk during your pregnancy. If you decide to reduce or eliminate dairy products, remember than processed milk presents less of a problem than whole milk.

 You may be able to continue eating yogurt and cheese while cutting back or eliminating milk. Since milk and milk products are important sources of calcium, be sure to calcium from other sources, such as broccoli, nuts, spinach, and canned salmon. Taking a calcium supplement would be a good idea if you are limiting your intake of dairy products. You need about 1,000 mg of calcium each day if you are between 18-50 years of age, whether you are lactating or not. While nursing mothers do lose some bone mass during lactation, by the time your baby has been weaned for a year, this lost bone mass in not only completely restored, but research has shown that women who breastfeed have half the risk of bone fractures as women who never breasted, and the longer you nurse, the lower the risk. Breastfeeding actually protects you from osteoporosis.

If you are anemic, don't worry that your milk won't have enough iron for your baby. Breastmilk contains less iron than formula, but the iron is used more efficiently, so your baby is less likely to become anemic, even if your iron levels are low. You will need to make iron supplements to make you feel better, but they will not affect the level of iron in your breastmilk. 

The guide to how much fluid to drink while nursing is to "drink to thirst". There is no evidence to show that forcing fluids will increase your milk supply. (Another "old wive's tale".)  Drinking too much water (over 12 glasses a day) can actually decrease your milk supply.  The current recommendation is to drink 6-8 ounces of water each day. The problem is that when you are a new mom, you often forget to take care of yourself while you are so immersed in taking care of the baby. Try drinking a glass of water or juice whenever you sit down to nurse your baby. Most mothers find that they are thirstier when they are nursing. If you produce large amounts of pale urine and are not constipated, then you are probably drinking enough. If your stools are hard and dry, and your urine is concentrated and dark, then you may need to increase your fluid intake. Remember that it is normal for your first void of the morning to be darker and more concentrated than at any other time during the day. 

A good rule of thumb is to take in 200-500 calories in excess of what you needed to maintain your weight before you were pregnant while you are nursing. Breastfeeding doesn't make you gain weight - in fact, you use up calories when you nurse, and helps you get rid of extra weight more quickly while you are nursing. Your body stores up fat during your pregnancy to provide the extra calories needed for milk production. It is easier to lose lower body fat (hips, buns, and thighs) when you are breastfeeding compared to the mom who is formula feeding. (YAY!) .

If you are a vegetarian, you probably will not need to change your diet unless your diet doesn't include any animal protein (vegan and macrobiotic diets). If you do not want to consume any animal products, you should consider taking a vitamin supplement containing vitamin B12. If you don't eat any dairy products, you should make sure to get enough calcium. I recommend that every nursing mom continue taking prenatal vitamins for as long as she lactates. 

Just like "drinking to thirst", you should "eat to hunger" while nursing. Studies have shown that most nursing mothers tend to lose up to one and a half pounds a month for the first 4-6 months after giving birth, and continue to lose weight at a slower rate beyond that time. They tend to lose more weight than formula feeding moms who take in fewer calories. If you want to lose weight (and most of us do - how depressing to still be wearing those old maternity clothes we got so sick of after the baby is born…) plan to do so slowly. It's best not to try to aggressively lose weight during the first couple of months after birth, because during that time your body needs to recover from childbirth and establish a good milk supply. Losing weight too quickly (more than one to one and one half pounds per week) has been associated with the release of environmental contaminants stored in body fat into the milk. 

Begin your weight loss program slowly when you are breastfeeding. Increase your activity level and eat less fat and sugar and more fruits and vegetables. Try to take in at least 1,800 calories each day, and definitely no less than 1,500 calories. Even moderate dieting during lactation can help you lose 4-5 pounds each month, but don't expect to lose body fat until about 2 weeks postpartum. The weight you lose immediately after birth is usually fluid loss. Mothers who breastfeed more frequently lose weight faster than mothers who nurse less often, and mothers who nurse for shorter periods of time tend to lose weight more slowly than mothers who nurse longer. You may get lucky and find that you can eat more than you ever could before and still lose weight while nursing. That was the case with me, but I did find that eating a whole container of Ben and Jerry's before bedtime every night kept me from losing weight as quickly as I would have liked. 

Despite one highly publicized but very questionable study about exercising during lactation, there is NO evidence that moderate exercise is anything but beneficial for nursing mothers (or anyone else, for that matter.) Plan to exercise after nursing so your breasts won't be full and uncomfortable. Wear a supportive sports bra. Drink a glass of water before and immediately after exercising. Drink more in hot weather. If you regularly lift weights or do other exercises involving repetitive arm movement, start slowly. If you develop plugged ducts, cut back and start again more slowly. Rinse off your breasts before nursing - some babies don't like the taste of the salt. Take walks with your baby. If you carry him in a backpack, his extra weight will use up even more calories. Weather permitting, go for lots of walks - this counts as exercise and gets you out of the house as well. It the weather keeps you inside, try carrying your little one in a sling while you do housework - and try dancing with him. You may feel silly, but he'll love it and so will you. Nobody will see you, and postpartum mothers are supposed to act a little bit goofy - the technical term is "baby brain". 

In summary: try to eat a nutritious diet while you are nursing, for your sake and your baby's. Don't worry if your diet isn't perfect, your milk will still be fine. If you want to lose weight, you will probably lose it without radically altering your diet while your are nursing. If you want to lose weight faster, start slowly, increase your activity level, and eat nutrient dense and healthy foods. Moderate exercise is good for both you and your baby. Try to make it fun so that you'll stick with your exercise program. Eat anything you want to in moderation, and remember that many mothers lose weight while lactating even without modifying their diet or exercise regimen. You will usually keep about three pounds of extra tissue in your breasts as long as you are nursing, so factor that into your weight loss goals. Enjoy nursing your baby, eat a healthy diet, and you most likely will lose weight while eating more food than you were used to eating before your little one arrived. 

Sources include: Breastfeeding and Human Lactation, 2nd Edition, Riordan an Auerbach, 1999

LLLI The Breastfeeding Answer Book, revised edition, 1997

The Complete Book of Breastfeeding, 3rd edition, Eiger and Wendkos olds, 1999