Is Fasting During Breastfeeding Safe?

There are doubts about the safety of fasting during breastfeeding, especially for the mother's health. We tell you more here.
Is Fasting During Breastfeeding Safe?
Saúl Sánchez Arias

Written and verified by the nutritionist Saúl Sánchez Arias.

Last update: 22 November, 2022

Intermittent fasting is one of the dietary protocols that’s most popular today. Certain benefits have been evidenced in terms of weight loss. It also contributes to improving metabolic health, reducing the risk of developing diseases. However, fasting during breastfeeding may not be advisable.

In the postpartum period, many women are concerned about regaining their pre-pregnancy figure. For this reason, they look for dietary protocols or strategies that allow them to reduce their daily caloric intake. However, this is a mistake, as we’ll see below.

The benefits of fasting

A woman breastfeeding her newborn.

During the last few years, a large number of scientific articles have come to light that talk about the benefits of the fasting protocol. This mechanism consists of avoiding calorie intake for at least 16 hours, which has a positive impact on body composition. This is according to research published in the journal Canadian Family Physician .

It’s also possible to effectively control blood glucose levels in diabetic patients by means of intermittent fasting. The protocol improves metabolic efficiency, leading to a greater capacity to oxidize fats and an increase in insulin sensitivity.

However, this isn’t a mechanism that can be implemented by everyone, although in most situations, it has very few associated risks. Its implementation is discussed in the case of adolescents, during pregnancy, and during breastfeeding.

Fasting during breastfeeding

Fasting during breastfeeding, as such, isn’t negative. The problem arises because this feeding protocol tends to produce an energy deficit throughout the day. At this time, the caloric requirements of the mother are still increased. Therefore, producing an imbalance in favor of expenditure isn’t the most appropriate.

The truth is that there are really no scientific trials investigating the specific effects of intermittent fasting on the metabolism of the breastfeeding mother. It’s true that it could be useful in treating diseases such as gestational diabetes, but there’s a lack of evidence in this regard.

However, it has been shown that it’s important to ensure a certain caloric surplus at this time. In fact, a nutrient deficit could increase the risk of developing postpartum depression, according to a study published in Maternal and Child Health Journal .

Religious fasting during lactation

In cultures where fasting is prescribed, there’s literature that recommends that the mother be excused from fasting. In fact, d uring the month of Ramadan, for example, from a religious point of view, pregnant or nursing mothers are exempted from the obligation to fast. This is especially the case if, for various circumstances, they fear for their own or their baby’s health.

Some approaches even go further by stating that they would be under any circumstances. Studies indicate that the dehydration of the nursing mother is greater; and, in very hot conditions, the composition of the milk changes, and the micronutrients decrease.

If fasting is chosen, the mother should drink plenty of fluids and eat a nutritious meal between dinner and dawn. This way, daytime losses would be avoided.

Improving habits is better than fasting during breastfeeding

In the absence of studies that prove the safety of fasting during breastfeeding for maternal health, it’s better to opt for other types of strategies. It’s possible to lose weight and improve body composition during this period without resorting to restrictive protocols.

It’s best to focus attention on the quality of the diet, opting for the consumption of fresh foods and reducing the intake of industrial ultra-processed foods. It’s important to ensure the presence in the diet of foods with high nutritional density in order to ensure that breast milk isn’t deficient in vitamins.

A mother smiling down at her breastfeeding daughter.

On the other hand, the physical workload can be increased by means of exercise, although following the principle of progressive loads. During the postpartum period, the woman’s body is still sensitive, so efforts should be made with a certain amount of restraint. Otherwise, sports injuries may occur.

There are better alternatives to fasting during breastfeeding

It hasn’t been proven that fasting during breastfeeding is bad. Nor that it has any health benefits. It’s likely that if a varied diet with a slight caloric surplus is proposed in the context of intermittent fasting, positive changes in the mother’s health can be achieved.

However, proposing a restrictive mechanism carries the risk of generating an energy deficiency, which wouldn’t be advisable in this context. For this reason, and in the absence of scientific evidence to the contrary, it’s best to follow a more classic dietary approach, with 3 or 5 meals per day.

This ensures the slight energy surplus necessary for breast milk to have a high nutritional density. This satisfies the baby’s requirements and avoids catabolism in the mother’s body, which could be negative in the medium term.

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The Importance of a Mother’s Diet While Breastfeeding
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The Importance of a Mother’s Diet While Breastfeeding

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  • Australian Breastfeeding Association. Religious fasting and breastfeeding. Mayo 2022.
  • Centers for Disease Control and Prevention. Breastfeeding. Maternal diet. U. S. Department of Health and Human Services. Mayo 2022.
  • Opie RS, Uldrich AC, Ball K. Maternal Postpartum Diet and Postpartum Depression: A Systematic Review. Matern Child Health J. 2020 Aug; 24 (8): 966-978. doi: 10.1007/s10995-020-02949-9. PMID: 32367245. https://pubmed.ncbi.nlm.nih.gov/32367245/
  • Rakicioglu N, Samur G, et al. The effect of Ramadan on maternal nutrition and compostion of breast milk. Pediatrics International. Junio 2006. 48 (3): 278-83.
  • Welton S, Minty R, O’Driscoll T, Willms H, Poirier D, Madden S, Kelly L. Intermittent fasting and weight loss: Systematic review. Can Fam Physician. 2020 Feb; 66 (2): 117-125.

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