Many new moms are looking for safe ways to drop the baby weight and wonder, "Does intermittent fasting work while breastfeeding?" If started a few months after giving birth, intermittent fasting is an effective form of weight loss when done properly.
Choosing a method of intermittent fasting that uses shorter fasting lengths, promotes adequate caloric intake, and focuses on a well-balanced, nutrient-dense diet is vital for a nursing mom's safety, maintaining her milk supply, and having weight loss success.
You read the books. You consulted your fellow baby moms. You were promised that if you breastfed your baby, the pregnancy weight would fall off.
You are still waiting…
If you're overweight, intermittent fasting while breastfeeding may be a better solution.
Many women report losing weight easily when breastfeeding. Research backing that claim revealed both short-term and long-term success with weight loss for nursing vs. non-nursing mothers (1,2,3).
On the other hand, other studies showed that breastfeeding made no difference in weight loss (4).
There are certain factors that can hinder weight loss while breastfeeding:
· Hungry and eating more frequently
· Moving less
· Sleep deprivation
· Not enough calories eaten
· Poor dietary choices
· Vitamin and mineral deficiency
Intermittent fasting is about extending the periods you are not eating. Some methods of intermittent fasting are based solely on the timing of eating, having no restriction on the number of calories consumed or which foods you can choose. Other ways of doing intermittent fasting require longer fasting lengths or limit calories. Choosing a safe, yet effective, method of intermittent fasting is important for the breastfeeding mother.
During the first few months of nursing, you may notice that you are hungry when intermittent fasting and breastfeeding. You may be hungry even if you are not fasting. That is because the nursing mother's body uses up its regular energy source (glucose) for her own metabolism and creates a milk supply. The body gets into a fasted state quicker (4-8 hours), and you feel hungry sooner than usual.
You may also find you are thirstier while breastfeeding. Your thirst is triggered by the release of oxytocin in the body from nursing (5).
Once cleared for physical activity, you can start exercising. Exercise has no effect on milk supply, but the additional calories burned can make you feel extra hungry. Although it's safe to exercise on an empty stomach, working out will put you in a fasted state quicker, so be mindful of how long you are going without eating (6).
Dieting isn't generally recommended for the first 6-8 weeks after giving birth when your milk supply is most sensitive to dietary changes. By the 3-6 month mark, most women have a well-established milk supply and breastfeeding routine, and it's okay to do intermittent fasting while breastfeeding. You will need to choose a method that is safe and won't affect your milk supply.
Studies have shown that changes in milk composition and supply occur when fasting 24 or more hours (7). These changes are also seen when consuming <1800 cal/day (8).
Because fasting longer than 24 hours and eating less than 1800 calories has been shown to decrease breast milk production, calorie-restricting or prolonged fasting methods, including the alternate day, 5:2, and eat-stop-eat methods are to be avoided.
In rare cases, breastfeeding moms who did prolonged fasts developed ketoacidosis, which can be life-threatening. Although it's natural to produce ketones during intermittent fasting when the body's energy source switches from sugar to stored fat, ketoacidosis is an over-production of ketones and unsafe (9).
Doing 16/8 intermittent fasting while breastfeeding (16 hours of fasting with an 8-hour, non-restricted eating window) is your best choice. It means a shorter fasting time and allows you to eat whatever you want and as much as you choose. Consider a 14/10 fasting schedule for the first few months as your body adjusts.
Make sure you are eating enough calories in your eating window and make nutritious food choices that fill you up and keep you satisfied. It is okay if it takes time to lose the baby weight. Losing one pound a week is considered safe for breastfeeding mothers (8).
Although short-term fasting doesn't affect milk production, some changes in the micronutrients (magnesium, potassium, zinc) in the breast milk do change when fasting less than 24 hours (10). This may be due to eating less frequent meals.
Therefore, it is important to eat enough nutrient-dense calories (lots of protein and veggies) during your eating window.
1) Foods high in protein and fiber help curb hunger because they are filling and take longer to digest.
2) Many people choose to do Keto and intermittent fasting while breastfeeding. The keto diet focuses on eating high fat/low carb foods. Limiting carbohydrates helps one get into the fasted state quicker. There is no research on a safe amount of carbs for nursing mothers, but too little can be dangerous, resulting in ketoacidosis. The Keto diet recommends eating <20g of carbs/day. That can be too little for nursing moms. If breastfeeding, it is suggested that you consume at least 50-100g of carbs/day and monitor how you feel (11).
3) High-fat diets have also been shown to create changes in the composition of breast milk, which may lead to potential changes in the newborn's development and put the child at risk for metabolic diseases in adulthood (12).
4) Stay hydrated during intermittent fasting and breastfeeding because 90% of breast milk consists of water, and proper hydration is needed for a strong milk supply. Drink plenty of water (don't overdo it) throughout the day since a large part of our water intake typically comes from food.
Intermittent fasting while breastfeeding 2-3 months after giving birth is safe if certain considerations are taken. To be safe wether you should fast or not, speak with your physician before starting with intermittent fasting. Shorter fasting times (<16 hours/day) are recommended.
Do a gradual buildup of fasting length and pay attention to how you feel. Avoid extreme high fat/low carb diets. They can cause issues for you and/or your child. Consume at least 1800 well-balanced, nutrient-dense calories per day.
Intermittent fasting isn't a quick fix for your baby weight, but with time and proper nutrition, it can become a healthy, permanent lifestyle and help you lose the pounds for good.
1. Jarlenski MP, Bennett WL, Bleich SN, Barry CL, Stuart EA. Effects of breastfeeding on postpartum weight loss among U.S. women. Prev Med. 2014;69:146-150. doi:10.1016/j.ypmed.2014.09.018
2. Sámano R, Martínez-Rojano H, Godínez Martínez E, Sánchez Jiménez B, Villeda Rodríguez GP, Pérez Zamora J, Casanueva E. Effects of breastfeeding on weight loss and recovery of pregestational weight in adolescent and adult mothers. Food Nutr Bull. 2013 Jun;34(2):123-30. doi: 10.1177/156482651303400201. PMID: 23964385.
3. Rooney BL, Schauberger CW. Excess pregnancy weight gain and long-term obesity: one decade later. Obstet Gynecol. 2002 Aug;100(2):245-52. doi: 10.1016/s0029-7844(02)02125-7. PMID: 12151145.
4. Neville CE, McKinley MC, Holmes VA, Spence D, Woodside JV. The relationship between breastfeeding and postpartum weight change--a systematic review and critical evaluation. Int J Obes (Lond). 2014 Apr;38(4):577-90. doi: 10.1038/ijo.2013.132. Epub 2013 Jul 29. PMID: 23892523.
5. James RJ, Irons DW, Holmes C, Charlton AL, Drewett RF, Baylis PH. Thirst induced by a suckling episode during breast feeding and relation with plasma vasopressin, oxytocin and osmoregulation. Clin Endocrinol (Oxf). 1995 Sep;43(3):277-82. doi: 10.1111/j.1365-2265.1995.tb02032.x. PMID: 7586595.
6. Dewey et al. (1994). Effects of dieting and physical activity on pregnancy and lactation. Am J Clin Nutr, 59( Suppl 2), 446s-453s. Institute of Medicine.
7. James RJ, Irons DW, Holmes C, Charlton AL, Drewett RF, Baylis PH. Thirst induced by a suckling episode during breast feeding and relation with plasma vasopressin, oxytocin and osmoregulation. Clin Endocrinol (Oxf). 1995 Sep;43(3):277-82. doi: 10.1111/j.1365-2265.1995.tb02032.x. PMID: 7586595.
8. Lauwers, J. & Swisher, A. (2015). Counseling the Nursing Mother: A Lactation Consultants Guide. Burlington, MA: Jones & Bartlett Learning.
9. Glossary. Diabetes Education Online. https://dtc.ucsf.edu/types-of-diabetes/type2/understanding-type-2-diabetes/how-the-body-processes-sugar/ketones/. Accessed June 23, 2021.
10. Rakicioğlu N, Samur G, Topçu A, Topçu AA. The effect of Ramadan on maternal nutrition and composition of breast milk. Pediatr Int. 2006 Jun;48(3):278-83. doi: 10.1111/j.1442-200X.2006.02204.x. PMID: 16732795.
11. Dr. Andreas Eenfeldt MD. Eating low carb or keto when breastfeeding. Diet Doctor. 2020 April 24. https://www.dietdoctor.com/low-carb/when-breastfeeding.
12. Chen Y, Wang J, Yang S, Utturkar S, Crodian J, Cummings S, Thimmapuram J, San Miguel P, Kuang S, Gribskov M, Plaut K, Casey T. Effect of high-fat diet on secreted milk transcriptome in midlactation mice. Physiol Genomics. 2017 Dec 1;49(12):747-762. doi: 10.1152/physiolgenomics.00080.2017.
