Anne Smith, IBCLC
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 wives tale.") Drinking too much water (over 12 glasses a day) can actually decrease your milk supply. The current recommendation is to drink six to eight glasses 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 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 it is normal for your first void of the morning to be darker and more concentrated than at any other time during the day.
Calories and weight
A good rule of thumb is to take in 200 to 500 calories more than 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.
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 every nursing mom continue taking prenatal vitamins for as long as she lactates.
Eating and losing weight
Just like "drinking to thirst", you should "eat to hunger" while nursing. Studies have shown most nursing mothers tend to lose up to one and a half pounds a month for the first four to six 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 four to five pounds each month, but don't expect to lose body fat until about two 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. If 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 you'll stick with your exercise program.
Eat anything you want to in moderation, and remember 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.