When you're breastfeeding, your dietary choices affect both you and your baby. While it is possible to lose weight while nursing, it's better to do so using a balanced approach instead of a no- or low-carb approach.
Milk Supply Problems
Cutting carbs or calories suddenly can cause your milk supply to dwindle, leaving you struggling to make enough breast milk for your baby's needs. Some moderately low-carb diets have multiple phases, so you might be able to skip the ultra-restrictive early phases and try a diet that gives you some healthy carbs and enough calories to maintain milk production. Aim for slow weight loss of 1 to 2 pounds a week and avoid dieting at all until around eight weeks after your baby's birth. At this point, your milk supply is fully established, so dieting won't derail that process.
Milk Quality Issues
When you embark on a drastic diet, your body's fat stores may release stored toxins that could get into your breast milk. If your diet restricts carbs, you could also be missing out on vital nutrients that your body needs to support your own and your baby's health. Women on an extremely carb-restricted diet often begin to produce types of chemicals called ketones, and it is unknown whether ketones can get into breast milk or whether they are a danger to a nursing baby.