During pregnancy most women will gain between 10 to 13kg. Breastfeeding is the time to start eating into the body fat reserves that were laid down during pregnancy! Breast milk production utilizes these fat stores and breastfeeding mums can lose about 1kg each month just by making breast milk. It may take up to a year to return to your pre-pregnancy weight but many women find the weight drops off quickly.
Limiting your energy intake, especially during the first few weeks of lactation, can affect your milk supply. Rapid weight loss can also release higher than normal levels of toxins from fat stores which can end up in the breast milk and may be harmful to your baby. It is not recommended that breastfeeding mothers follow a weight loss diet, just wait until you have finished breastfeeding and re-assess your weight then.