Summary: New research using a rat model shows that when mothers consume a high-fat, high-sugar “Western” diet during pregnancy and lactation, their pups gain extra weight during suckling, display a stronger immediate preference for fatty taste after weaning, and develop long-lasting alterations in brain reward circuits linked to eating behavior. Childhood access to a balanced diet reduced the early preference for fat but did not eliminate changes in the brain’s reward systems.
Researchers in France report that maternal consumption of energy-dense, palatable foods during pregnancy and breastfeeding leads to heavier offspring at weaning, an early heightened preference for fat, and persistent changes in neural circuits that regulate reward and feeding.
The modern Western diet is characterized by high levels of fat and sugar found in many processed foods, snacks, and desserts. Overconsumption of these energy-dense foods contributes to rising rates of obesity and metabolic disease worldwide. Beyond metabolic effects, these foods also shape eating behavior through changes in the brain’s reward pathways, which modulate pleasure and motivation related to food.
Emerging evidence suggests that a mother’s diet during pregnancy and lactation can influence the child’s later risk of obesity. The underlying biological mechanisms are not fully understood, so scientists conducted an experimental study in rats to track how perinatal exposure to a Western-style diet affects offspring weight, taste preferences, and the development of reward-related brain regions.
In the study published in Frontiers in Endocrinology, pregnant and nursing rats were fed either a high-fat/high-sugar “Western Diet” (WD) or a balanced control diet. Researchers monitored the offspring from birth through childhood, adolescence, and into early adulthood. After weaning, the pups primarily received a balanced diet, but at selected times investigators tested the animals’ preference for a fatty versus a non-fatty liquid. The test liquids were designed to be non-caloric at the concentration used, allowing measurement of taste preference rather than direct nutritional effects.
Pups born to mothers on the Western Diet were similar in weight at birth but gained significantly more weight during the suckling period and were heavier at weaning. This weight gain may reflect changes in maternal milk composition or quantity induced by the mother’s energy-rich diet.
Immediately after weaning, pups from WD mothers showed a strong preference for the fatty liquid compared with pups from control mothers. When the same preference test was repeated in adolescence, both groups displayed a high preference for fat. Notably, the increased fat preference in WD-exposed pups diminished over a few days during the adolescent test, suggesting a possible compensatory response that limits further consumption when exposed to fat. By adulthood, both WD-exposed and control groups showed similar levels of preference for fat.
Beyond behavioral taste tests, the researchers examined gene expression and neuroanatomical changes in brain areas that mediate reward and feeding, including the hypothalamus and mesolimbic pathways. Offspring from WD mothers exhibited significant alterations in these reward circuits. In particular, the study identified changes in genes related to dopamine signaling during childhood and adolescence and, by adulthood, prominent modifications in genes associated with the GABAergic system, serotonin receptors, and molecules involved in hypothalamic remodeling.
These neural changes indicate that perinatal exposure to a palatable, high-energy diet can lead to lasting plasticity in homeostatic and hedonic brain networks that influence eating behavior. Importantly, while early diet influenced transient fat preference, the long-term reorganization of reward and hypothalamic circuitry persisted even when later diet was balanced.
Vincent Paillé, one of the study authors, notes that prior work showed persistent fat preference when unlimited junk food is available during development. In contrast, the current study suggests that access to a balanced diet after weaning may reduce heightened fat preference in adolescence, although underlying neural alterations remain. The authors emphasize that these changes could alter how the brain integrates reward and metabolic signals, potentially affecting responses to stress or free access to high-fat foods.
Funding: The study was supported by Region des pays de la Loire, LCL Foundation, SanteDige Foundation, and INRA Metaprogram DIDIT.
Source: Emma Duncan – Frontiers in Endocrinology. Original research: “Perinatal Western Diet Consumption Leads to Profound Plasticity and GABAergic Phenotype Changes within Hypothalamus and Reward Pathway from Birth to Sexual Maturity in Rat,” by Julie Paradis, Pierre Boureau, Thomas Moyon, Sophie Nicklaus, Patricia Parnet, and Vincent Paillé. Published online August 29, 2017.
Abstract (summary)
Maternal consumption of energy-dense, palatable food during gestation and lactation raises offspring obesity risk and influences hedonic feeding behavior. This longitudinal rat study examined the effects of a perinatal Western Diet on offspring fat preference, gene expression, and structural changes in mesolimbic dopaminergic networks from childhood to sexual maturity. Perinatal WD caused long-lasting reorganization of homeostatic and reward circuits without producing a sustained change in fat preference into adulthood. WD-exposed offspring showed childhood increases in genes linked to dopamine signaling, a transient adolescent response suggesting compensatory downregulation, and adult alterations in GABAergic genes, serotonin receptors, and hypothalamic remodeling markers. These findings reveal complex, age-dependent effects of maternal diet on neural pathways that control feeding and underscore the need for further functional studies to determine how circuit remodeling influences vulnerability to overeating or obesity.