A new study published in The Journal of Nutrition suggests that mothers’ consumption of total fat, saturated fat, and added sugar during late pregnancy and the early postpartum period is positively correlated with body fat levels of breastfed infants at 6 months of life.

Maternal nutrition is an important aspect of prenatal care and successful lactation, and a healthful diet with adequate macronutrient and micronutrient intake is recommended during pregnancy and lactation. The relation between specific maternal dietary components during this period and infant body composition has not been thoroughly examined. In a study conducted among healthy breastfeeding women and their infants living in Minnesota and Oklahoma, researchers asked whether maternal dietary patterns during late pregnancy and breastfeeding are related to an infant’s body fat at 6 months of age.

To address this question, Dr. Emily Nagel (School of Public Health, University of Minnesota–Twin Cities) and colleagues studied 349 mothers and their infants enrolled in the Mothers and Infants Linked for Healthy Growth (MILk) study. Average maternal dietary intakes were assessed and characterized based on how closely they reflected recommendations put forth in the 2015 version of the Dietary Guidelines for Americans.

After controlling for important factors such as maternal weight and caloric intake, the researchers found that greater maternal intake of total fat and saturated fat was linked to higher infant percent body fat. Similarly, after adjusting for infant length and age, mothers’ intake of added sugar was positively associated with infant weight.

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When considering these study findings, it is important to remember that the optimal body fat percentage for infants at 6 months of age has not been established, and the overall impact of infant adiposity at this age on later health is not known. Furthermore, the observed associations were not large in magnitude despite maternal consumption of dietary fat, saturated fat, and added sugars above the recommended levels.

Although the researchers acknowledged several limitations of their study (e.g., the women were highly educated with high incomes and do not represent the US population; the study was observational), they concluded that their data suggest maternal diet might impact infant body composition during the first 6 months of life. They also urge additional research be conducted to understand whether these relationships might be driven by differences in breastmilk composition.


Nagel EM, Jacobs D, Johnson KE, Foster L, Duncan K, Kharbanda EO, Gregg B, Harnack L, Fields DA, Demerath EW. Maternal Dietary intake of total fat, saturated fat, and added sugar is associated with infant adiposity and weight status at 6 mo of age. The Journal of Nutrition, Volume 151, Issue 8, August 2021, Pages 2353–2360, https://doi.org/10.1093/jn/nxab101.

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