Lactating mothers have high energy demands. For the first three months, weight loss due to breastfeeding mainly happens due to increased calorie consumption.

Research indicates that a lactating woman consumes 450-500 kcal/day during weaning, in addition to her routine energy expenditure of ∼200 kcal/day, making energy expenditure 1.4 times more than the energy required for regular physical activity. ⁽¹⁾

Due to certain factors and less activity during gestation, women are more prone to gaining weight. However, postpartum women can easily shed pounds by combining a low-calorie diet with light exercise.

Hormones play an essential role in losing weight during breastfeeding. In late pregnancy, human chorionic somatomammotropin, cortisol, prolactin, and glucagon exert anti-insulinogenic and lipolytic effects, leading to insulin resistance and peripheral fat loss while gaining visceral fat. ⁽²⁾

Catecholamines(Epinephrine, Nor-Epinephrine) significantly rise during gestation and postpartum. During gestation, these hormones increase metabolism to meet the energy demands of the growing fetus, while postpartum, increased metabolism facilitates milk production. ⁽³⁾

Lipoprotein lipase (LPL) is significantly involved in reducing postpartum fat deposition. Research indicates lower levels of LPL in lactating mothers than in non-lactating mothers, which can lead to adipose tissue recession. It facilitates a lot in losing weight during breastfeeding tenure. ⁽⁴⁾

During gestation, circulating triglycerides and glucose increase due to increased insulin resistance and the lipolytic effect of HCS, cortisol, and glucagon, leading to hyperglycemia and hyperlipidemia.

Milk contains around 3.8% fat content. Fat mobilization is essential to meet milk production requirements.

Several studies showed that lactating mothers have high HDL(good cholesterol) levels, so lactation is also associated inversely with the incidence of metabolic syndromes, HTN, and Ischemic Heart diseases. ⁽⁵⁾

Fat mobilization starts after three months of delivery when levels of gestational hormones return to normal while catecholamines remain persistently elevated. ⁽⁶⁾

Gestational insulin resistance results from a “metabolic syndrome”-like condition mediated by pregnancy hormones. The postpartum increase in insulin sensitivity is explained theoretically by the β-cell rest theory. During lactation, prolactin induces serotonin production in β-cells. Serotonin facilitates the proliferation of β-cells, and its anti-oxidant property leads to improved stability of β-cells. ⁽⁷⁾

Insulin sensitivity mediated by lactation sustains its effects for up to 3-4 years compared to non-lactating mothers. This acts as a long-term preventive measure against Type-II DM.

GLUT receptors also play a key role in non-insulin-mediated glucose uptake. Prolactin increases the expression of GLUT-1 receptors in mammary glands, leading to NIMGU. Studies also reveal that insulin-independent glycemic control works more effectively during lactation than insulin-dependent glycemic control. ⁽⁸⁾

Several animal and human studies indicate the leptin hormone(released by adipose cells) significantly drops during lactation, leading to a feeling of satiety. Leptin maintains energy balance by signaling food requirements as needed. ⁽⁹⁾

Moreover, some cases are associated with postpartum pinks and blues. It induces feelings of low esteem or euphoria and ultimately alters eating behavior. ⁽¹⁰⁾

In some cases, the mother is equally engaged in physical activity and breastfeeding her child. It leads to a negative calorie balance, as intake does not meet the body’s energy requirements. It is common in low—to mid-socioeconomic classes. In this situation, more weight is lost than expected. Mothers should be educated to follow their diet plans.

Pre-gestational obesity status is also essential to assess the postpartum likelihood of losing weight during breastfeeding.

Non-pregnant obese ladies are at a higher risk of developing gestational complications, i.e. gestation DM, fetal macrosomia, and postpartum non-production of milk.

It is essential for ladies to maintain their weight for better physical well-being and to prevent pregnancy complications.

In some cases, weight gain occurs after delivery, caused by irregular eating behaviors (excessive calorie intake with a mindset to compensate for lactation and energy boost) and lack of physical activity.

Postpartum light physical activity and a balanced nutrition plan are key to success.

1. https://www.sciencedirect.com/science/article/pii/S0002916522042733?via%3Dihub
2. https://www.sciencedirect.com/topics/medicine-and-dentistry/human-placenta-lactogen
3. https://www.sciencedirect.com/science/article/pii/S0002916522042733?via%3Dihub#s0090
4. https://pmc.ncbi.nlm.nih.gov/articles/PMC3006166/#S1
5. https://doi.org/10.1016/j.ajog.2008.10.001
6. https://pmc.ncbi.nlm.nih.gov/articles/PMC3006166/#S11
7. https://www.science.org/doi/10.1126/scitranslmed.aay0455
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC9901550/#j_jtim-2022-0036_s_002
9. https://pmc.ncbi.nlm.nih.gov/articles/PMC9901550/#j_jtim-2022-0036_s_002
10. https://academic.oup.com/book/29489/chapter/247373944