It's best not to diet while breastfeeding. All the nutrients your baby receives from breastfeeding depend on the quality of the food you eat. Breastfeeding places more demands on your body than pregnancy. Your body burns up to 1000 calories a day just to produce milk. When breastfeeding, you need to eat an extra 500 calories a day.
Breastfeeding and Pregnancy Prevention
Hormonal changes that go along with breastfeeding make it less likely that you'll get pregnant, but don't rely on breastfeeding to protect you against pregnancy. You need to use some type of protection when you resume intercourse.
Don't use a regular oral contraceptive pill while you are breastfeeding. The hormones in regular oral contraceptives get into your milk and are passed along to your baby, possibly causing problems with the baby's development. The minipill is a good choice, or choose some other form of birth control until you are finished breastfeeding.
Spicy Foods and Caffeine
Most substances you eat or drink (or take orally, as medication) can pass to your baby in your breast milk. Spicy foods, chocolate and caffeine are just a few things your baby can react to when you ingest them. Caffeine in breast milk can cause irritability and sleeplessness in a breastfed baby. Be careful about what you eat and drink while breastfeeding.
Insufficient Milk Syndrome
Insufficient milk syndrome is rare. The baby becomes dehydrated because of breastfeeding problems, such as the mother's low milk supply or the baby's failure to drink enough milk.
This situation can happen when a mother has the idea that breastfeeding is the only "right" method of feeding and takes it to extremes. She views using a bottle, even when breastfeeding complications occur, as a personal failure. It can also happen when a mother is unable to produce enough breast milk, due to genetic defect, injury or breast surgery. Again, this problem is rare.