Yes, it is normal to lose weight during breastfeeding, but some women may keep the same or even gain some weight. This depends on diet, exercise and metabolism.
During breastfeeding, it is possible to go on a weight loss diet, but be careful. It is not advisable to start the diet before the baby is two months old, as it can significantly affect milk production. On the other hand, the diet should be very unrestrictive and lose weight slowly. If the weight loss is too rapid, it is possible to release toxins derived from body fat into the breast milk, which is harmful to the baby.