Study shows maternal fatty food aroma exposure increases offspring obesity risk - Video

The development of obesity in children may begin before birth, influenced by factors as subtle as the smell of fatty foods experienced during pregnancy.

Researchers at the Max Planck Institute for Metabolism Research discovered that exposure to the scent of fatty foods, such as bacon, in pregnant mice-even when their diet was low in fat-can prime their offspring for a higher risk of obesity and insulin resistance later in life.

Their work, published in Nature Metabolism reveals how prenatal and early postnatal environments can shape long-term metabolic health.

In this study, pregnant mice were fed a healthy diet infused with the aroma of fatty foods. Despite the mothers’ unchanged metabolism, their offspring displayed heightened sensitivity to high-fat diets, gaining more weight and showing signs of impaired insulin signaling compared to controls.

Analysis of the offspring’s brains identified changes in critical regions involved in reward and hunger, notably the dopaminergic system linked to motivation and AgRP neurons controlling appetite and metabolism. These neural adaptations resembled those found in genetically obese mice, suggesting the scent exposure alone rewired brain circuits tied to energy balance.

Further experiments demonstrated that fetuses and newborn mice encounter these odors both in the womb and through breast milk. Remarkably, artificially stimulating the brain pathways activated by fatty food smells during early life was enough to trigger obesity in adulthood, indicating a powerful early-life programming effect.

This research shifts the focus from maternal obesity alone to the sensory environment shaping fetal development. While overweight mothers increase obesity risk in children, even lean mothers consuming diets with fatty aromas might unknowingly influence their offspring's future weight. Notably, only ingestion of these odor-containing diets—not mere exposure to smells—led to these changes.

Flavoring agents used in processed foods often include similar compounds found to replicate these effects, raising concerns about widespread additive use during pregnancy and lactation. The findings highlight the urgent need for further investigation into how maternal diet and aroma exposure may contribute to the global obesity epidemic and how modifying these exposures could promote healthier metabolic outcomes from the start of life.

This groundbreaking study expands our understanding of early obesity risk, emphasizing that a mother's dietary experience and its sensory signals profoundly shape her child’s lifelong health trajectory.

REFERENCE: Casanueva Reimon, L., et al. (2025). Fat sensory cues in early life program central response to food and obesity. Nature Metabolism. DOI: 10.1038/s42255-025-01405-8. https://www.nature.com/articles/s42255-025-01405-8