Research into the lifting of postwar sugar rationing in the UK suggests that the first 1,000 days of life may leave a lasting mark on health, with reduced sugar exposure linked to lower risks of several conditions decades later.
During wartime rationing, adults were limited to about 3 tablespoons (40g) of sugar a day, while children were restricted to less than a tablespoon. Babies and very young children were expected to have little or no added sugar. In 1953, restrictions on sweets and chocolate were lifted in February, followed by sugar in September, and by the second half of 1954, average sugar consumption had almost doubled.
Natural experiment from history
This abrupt change created a natural experiment that scientists are now studying. Dr Jiazhen Zheng at Hong Kong University of Science and Technology in Guangzhou, China, who worked on several recent studies, said: "In September 1953, sugar availability changed quite abruptly at the population level, largely because of policy rather than individual choice. In a sense, history created an experiment that we could never deliberately run over a human lifetime."
A study published in the journal Science two years ago, led by Dr Tadeja Gračner at the University of Southern California, used UK Biobank data to compare the health of people born shortly before and after rationing ended. Those exposed throughout their first 1,000 days had a 35% lower risk of type 2 diabetes and a 20% lower risk of high blood pressure than those who never experienced rationing.
Broader health associations
Further studies drawing on UK Biobank data have linked reduced sugar exposure to lower risks of cardiovascular disease, liver disease, respiratory issues, dementia, and broader measures of ageing. Zheng said: "I have been more struck by the consistency across different organ systems than by any single effect estimate."
Gračner added: "Many of these outcomes are connected. Diabetes, hypertension and obesity are major risk factors for cardiovascular disease, cognitive decline and several other conditions, so if early-life sugar restriction affects those upstream risks, associations across a broad set of related outcomes are what one would expect."
Mental health and ageing links
In August, Prof Nophar Geifman at the University of Surrey and colleagues reported that people who spent the full first 1,000 days under sugar rationing had a 33% lower risk of being diagnosed with anxiety than those born after rationing ended. They were also less likely to report a preference for sweet foods decades later.
Geifman said: "Despite increased sugar consumption after rationing, early nutritional environments appear to have lasting relevance for mental health." She noted the brain undergoes rapid development in the womb and early years, which could make it sensitive to nutritional environment.
Zheng's ageing study found that people exposed to rationing scored about a year younger on several measures of biological age, with differences in proteins involved in pathways that help cells respond to nutrients.
Comparison with famine studies
Researchers have long used famines as natural experiments, such as the Dutch "hunger winter" of 1944-45. Prof LH Lumey, emeritus professor of epidemiology at Columbia Mailman School of Public Health in New York, said the most reliable findings are increased risks of overweight, obesity, and type 2 diabetes.
Zheng stressed that British sugar rationing was not famine. "It selectively constrained sugar intake while the broader diet remained relatively adequate," he said, adding that the quality and timing of nutrition during early development can have consequences across the life course.
Geifman cautioned: "There's no causality implied. It is an association." Many studies draw on overlapping UK Biobank participants, so they cannot be regarded as independent replications. Gračner said: "The strongest evidence will ultimately come from triangulation across independent datasets and research designs."
Lumey called the findings "a great first step, not the final word," noting that the risk could be 30% or 50% higher, and the critical window could be the first 1,000 days or only gestation.
Current UK guidelines recommend free sugars should not exceed 30g a day for adults and children aged 11 and over, with lower amounts for younger children, and the NHS advises that sugars should not be added to food or drinks given to babies. Average UK consumption is roughly twice this level.
The studies suggest that keeping sugar intake closer to recommended levels may have benefits extending much further into later life than previously recognised, though they do not prove that severe dietary restriction is beneficial.
