Gestational diabetes alters early brain response to food cues during pregnancy

A Lausanne study reveals that metabolic health during pregnancy influences how the brain processes food images, with pregnant women with gestational diabetes showing distinct electrical activity patterns within milliseconds of viewing food cues, impacting appetite and eating behaviour.

Researchers in Lausanne have found that pregnancy-related metabolic health may shape how the brain responds to food cues, with women diagnosed with gestational diabetes showing different patterns of electrical brain activity from healthy pregnant controls when viewing images of food. The study, published in Nature Communications, examined 39 women in the third trimester of pregnancy after data-quality exclusions and compared their responses during a brief visual discrimination task while recording EEG, or electroencephalography, which measures electrical activity at the scalp. The work suggests that differences in food processing can appear very early, within about 127 to 155 milliseconds after a picture appears.

The participants were recruited at Lausanne University Hospital and included women diagnosed with gestational diabetes between 24 and 32 weeks of pregnancy as well as healthy controls with a pre-pregnancy body mass index of 25 or below. The researchers excluded women with pre-existing diabetes, eating disorders, current insulin treatment, vegetarian or vegan diets and several other factors that could affect the experiment. Before the visit, the women completed medical and lifestyle questionnaires, and they were asked to eat a balanced lunch at noon to reduce differences in satiety during the afternoon testing session. The Swiss Society for Nutrition says its balanced-plate model aims to combine vegetables or fruit, starchy foods and protein-rich foods in roughly equal parts, while national dietary guidance promotes balanced eating, sustainability and health.

During the experiment, each participant saw 240 images, including food and non-food objects, while performing a quick button-press task to identify whether each picture showed food or not. The food images were split into four groups based on fat and carbohydrate content, allowing the researchers to compare high-fat and low-fat as well as high-carbohydrate and low-carbohydrate cues. The team then analysed the EEG data using measures of global field power, scalp topography and source estimation, methods that can help show not only when the brain responds but also how the pattern of activity changes across the scalp and within the brain.

The study’s broader implication is that gestational diabetes may alter the earliest stages of how food is noticed and evaluated, not just later decision-making. That matters because pregnancy already involves major hormonal and metabolic shifts, and gestational diabetes raises the stakes for both maternal and fetal health. While the study was small and exploratory, it adds to a growing view that metabolic conditions in pregnancy can influence brain responses to everyday food cues in ways that may affect appetite and eating behaviour.