Can You Drink Slim Fast While Nursing?

The Slim-Fast system uses meal-replacement shakes and bars to help participants shed pounds. Women following the Slim-Fast system typically consume a shake or meal replacement bar for breakfast and lunch, two healthy snacks and a low-calorie dinner. Although the convenience and ease of the Slim-Fast program might appeal to time-pressed breast-feeding mothers eager to lose their remaining postpartum pounds, the program can potentially deprive nursing moms of the calories and nutrients they need to maintain a healthy milk supply.

Breastfeeding women need about 500 more calories a day than non-nursing mothers. Your individual caloric needs will vary depending upon your baby's age and frequency of nursing, as well as your weight and metabolism. Most women need at least 1,800 calories, according to La Leche League International. La Leche League cautions that a low milk supply can result from diets that provide breastfeeding mothers with fewer than 1,500 calories a day. Dieters on the Slim-Fast program typically consume 1,200 calories.

Moderate weight loss of 1 lb. or less a week is fine for breastfeeding moms, according to La Leche League International. Losing weight more rapidly might introduce pesticides and contaminants stored in a nursing mother's fat into the bloodstream, where it can end up in her milk supply. The Slim-Fast website suggests that most dieters following their program lose between 1 to 2 lbs. a week.

On the Slim-Fast website, registered dietitian Ali Auerbach offers reassurance on the safety of Slim-Fast products. Slim-Fast shakes and bars do not contain appetite suppressants, drugs or stimulants that can pass through your milk supply and harm your baby. Many of the products do, however, contain artificial colorings, flavorings and sweeteners, including sucralose, acesulfame potassium and aspartame, which your baby can potentially ingest through breast milk. Lactation consultant Kelly Bonyata, the owner of the breastfeeding advice site Kellymom.com, says there is a lack of data as to what quantities of these additives pass into the breast milk and whether these artificial sweeteners are safe for infants.

Instead of following the full Slim-Fast program, nursing moms can drink a shake or eat a bar occasionally as healthy snack or meal replacement. You can also make your own shakes by combining low-fat milk with fresh fruit and a source of fiber, such as flax seed or wheat germ. Nursing moms just need to make sure their daily caloric intake falls within the recommended guidelines. Check with your doctor before starting a diet plan to ensure it is safe and appropriate for your situation.