How much sugar a baby is exposed to in the womb and during the first two years of life could shape their mental health decades later, according to a study published in Translational Psychiatry. The research found that people who were exposed to less sugar in early life had a lower risk of developing anxiety as adults, as well as noticeable differences in brain structure and even their preference for sweet foods.
The team from the University of Surrey is the first to look at how sugar exposure in the critical first 1,000 days of life (from conception to around age two) may be linked to mental health later on.
A Unique Window Thanks to Post-War Rationing
To tease out these effects, the researchers took advantage of a one-off natural experiment: post-war sugar rationing in the UK. From the 1940s until 1953, families had their sugar intake limited, often to around 40g a day for adults. After rationing ended, sugar consumption shot up quickly, giving scientists a rare chance to compare generations of babies raised on very different diets.
The team analysed medical data from more than 45,000 UK Biobank participants born between 1951 and 1956, split into several groups depending on how long they had been exposed to rationing (either only in the womb, or during pregnancy and up to 6, 12, 18 or 24 months of age). Two control groups, including children born in Ireland (where rationing wasn’t in place), were also studied.
What the Study Found
The results were striking. Those who were exposed to the longest period of rationing (in utero and through their first two years) were around a third less likely to develop anxiety in adulthood than those who were never rationed. Women in particular, who had no sugar restrictions in early life or had them for only a short time, were more likely to develop anxiety later on.
An association between early sugar exposure and depression also showed up, but it weakened once the researchers accounted for other factors, suggesting that depression may be shaped more by diet later in adulthood than by early-life sugar.
Dr Hana Navratilova from IPB University in Indonesia, who led the research while at the University of Surrey, said: “Research has shown that sugar exposure during the first 1000 days of life may influence the risk of suffering from several chronic diseases, such as diabetes. Because we’ve seen in our previous work links between the liking of sugary foods and mental health issues, we were specifically interested in understanding if having sugar in early life could contribute to incidences of mental health issues such as depression and anxiety later in life.”
She added: “Knowing the full impact that sugar can have on our physical and mental health, across our lifespan, could help inform public health policy and reshape our diets.”
Differences in the Brain and in Taste
The team didn’t stop at mental health. They also looked at brain scans. Out of 139 brain regions, 80 showed significant differences in grey matter volume between people with different rationing histories. More detailed analysis found that 11 of those regions, including parts of the cerebellum, showed clear differences between most rationed groups and those who had never experienced rationing.
Food preferences were affected too. People who had the longest exposure to rationing in early life reported a lower taste for sweet foods as adults, suggesting that early diet can shape taste for a lifetime.
A Rare and Valuable Dataset
Professor Nophar Geifman, Professor of Health and Biomedical Informatics at the University of Surrey and senior author, said: “The UK Biobank is a treasure trove of data that allowed us to look at this post war diet rationing, giving us unique insight into the impact of sugar exposure on our mental health. It is highly unlikely that this sort of dataset would exist again, whereby so many people did not have excess sugar in their diets and then had it slowly phased in over a prolonged period of time.”
She added: “What we have found is that rationing of sugar in early life is linked to reduced sweet liking and lower risk of anxiety. Despite increased sugar consumption after rationing amongst participants, early nutritional environments appear to have lasting relevance for mental health.”
The Bigger Picture
It’s important to note that this study doesn’t prove sugar directly causes anxiety. Rationing changed many aspects of family diets, not just sugar. But the signal is strong enough to deserve attention, and it adds to growing evidence that what we eat in our earliest years shapes not just our bodies but our minds and even our food preferences for life.
If anything, this research reinforces how much the first 1,000 days matter. Policies and parenting choices around early-life nutrition could have ripple effects stretching far into adulthood.
Navratilova, H.F., Whetton, A.D., & Geifman, N. (2026). Dietary sugar exposure in early life and risk of adult mental health disorders: UK Biobank cohort study. Translational Psychiatry. DOI: 10.1038/s41398-026-04376-w