Summary: New research from the Max Planck Institute indicates that exposure to fatty food odors during pregnancy and early postnatal life can reprogram developing neural circuits and increase the risk of obesity and insulin resistance later in life. In animal experiments, offspring whose mothers consumed a low-fat but bacon-flavoured diet showed stronger weight gain and metabolic impairment when fed a high-fat diet as adults, even though the mothers themselves remained metabolically healthy.
The study links early-life sensory exposure to long-lasting changes in brain systems that regulate hunger, reward and whole-body metabolism. These findings raise the possibility that prenatal and neonatal exposure to food-related smells may shape metabolic health independently of maternal body weight or calorie intake.
Key facts
- Odor exposure effect: Exposure to fatty food smells during development increased later-life obesity and insulin resistance in animal models.
- Brain circuit changes: Reward-related dopamine pathways and AgRP hunger neurons were permanently altered in exposed offspring.
- Diet independent: Effects occurred even when mothers ate a low-fat, nutritionally balanced diet that simply included fat-related flavour cues.
Research team
A research team at the Max Planck Institute for Metabolism Research conducted controlled experiments in mice to separate the sensory components of a high-fat diet from its caloric and nutritional components. By feeding pregnant and lactating dams an isocaloric, low-fat chow with added bacon flavouring, they tested whether fat-associated sensory cues alone could program offspring metabolism.
Although the mothers’ metabolic profiles did not change, their offspring displayed greater susceptibility to weight gain and developed insulin resistance when later exposed to a high-fat diet. Detailed neurobiological analysis revealed persistent alterations in mesolimbic dopaminergic circuits involved in reward and motivation, and in Agouti-related peptide (AgRP) neurons that control hunger and energy balance. These neural changes made the offspring’s central responses to dietary fat resemble those seen in genetically or diet-induced obese animals.
The investigators also demonstrated that fetuses and newborn pups encounter fat-related odours: odour molecules are present in the womb environment and are transferred through maternal milk during breastfeeding. Importantly, the study showed that while simple passive exposure to fat-related odours in the neonatal period was not sufficient by itself to produce the metabolic outcomes, pairing sensory activation with caloric intake — and experimentally stimulating sensory circuits during feeding — potentiated the effect and promoted obesity in adulthood.
What does this mean for humans?
These animal-model results suggest a previously underappreciated pathway by which a mother’s diet could influence a child’s long-term metabolic health: not only through nutrients and calorie availability, but also via sensory cues such as the smell of fatty foods encountered before birth and during early life. The findings do not prove the same effects occur in humans, but they identify a plausible mechanism worthy of further study.
Crucially, the experiments indicate that ingestion of the food containing fat-related odours was required for the observed programming effects; mere environmental exposure to the scent without maternal consumption did not reproduce the outcomes. This nuance underscores that the exposure route and context matter when considering potential implications for human pregnancy and lactation.
Lead researcher Sophie Steculorum commented that these results expand the focus beyond maternal metabolic health alone and point to how sensory experiences during development — specifically odour cues associated with fatty foods — could shape offspring brain circuits that regulate eating behaviour and metabolism.
Flavouring agents and food additives
To create the bacon-flavoured diets used in the study, researchers used commercial flavouring agents. Analysis revealed that some of these agents share components used as food additives. In the experiments, one additive alone replicated the programming effect on offspring metabolism. The authors emphasize the need for additional research to determine whether consumption of certain flavouring compounds during pregnancy or breastfeeding could affect neurodevelopment and long-term metabolic health.
Key questions answered
A: In this animal study, exposure to fatty-food odours during pregnancy and breastfeeding increased obesity risk later in life. Further research is needed to establish whether the same pathway applies to humans.
A: The study found lasting changes in brain systems that control reward and motivation (mesolimbic dopamine circuits) and in Agouti-related peptide (AgRP) neurons that regulate hunger and energy balance.
A: The research highlights a potential risk pathway but does not establish causation in humans. Direct clinical studies are required to determine relevance for people.
Editorial notes
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full by the editorial team.
- Additional context and clarification were added by staff writers.
About this research news
Author: Katharina Link (Max Planck Institute)
Source: Max Planck Institute for Metabolism Research
Contact: Katharina Link – Max Planck Institute ([email protected])
Image: Image credit: Neuroscience News
Original research: Open access. Title: “Fat sensory cues in early life program central response to food and obesity” by Sophie Steculorum et al., published in Nature Metabolism.
Abstract (summary)
Maternal obesity predisposes offspring to metabolic disease. This study demonstrates that sensory components of a high-fat diet—specifically fat-related odour cues—are sufficient to alter metabolic health in offspring independent of the diet’s caloric or obesogenic properties. Using a bacon-flavoured, isonutritional diet during gestation and lactation, researchers showed that developmental exposure to fat-related odours programs offspring to display metabolic inflexibility and increased adiposity when challenged with a high-fat diet in adulthood. These early sensory cues shift mesolimbic dopaminergic circuits and AgRP neuron responsiveness, producing neural signatures similar to those observed in obese mice. While passive neonatal exposure to odours or optogenetic activation of sensory circuits alone was not sufficient, coupling sensory circuit stimulation with caloric intake amplified the effect and precipitated obesity. Overall, the findings identify fat-related sensory cues during development as signals that can prime central responses to food and long-term regulation of whole-body metabolism.