During and in the aftermath of World War II, between January 1940 and September 1953, the United Kingdom rationed most food items. For some chunk of those fourteen years, everything except fish and fresh fruit and vegetables (which were still often in short supply) could only be legally acquired under strict limits and with government-issued coupons.
Sugar was among the restricted pantry staples. Sweets and candies were rationed too, as people kept calm and carried on. Individual adults were allotted about 40g of sugar per day and children over two were limited to less than 15g.
Despite the less-than-ideal economic conditions that spurred the policy, new research on tens of thousands of people shows cutting sugar conferred lifelong health benefits to those conceived amid rationing. The study, published October 31 in the journal Science, indicates that limiting sugar exposure in the 1,000 days post-conception (including the in-utero period and first two years of life), lowers the risk of chronic disease later on.
The group of people born before or just after the end of sugar rationing were 35 percent less likely to develop type 2 diabetes, 30 percent less likely to become obese, and 20 percent less likely to develop hypertension during their lifetimes than their un-rationed peers, per the study. If those in the rationed group did develop diabetes or hypertension, they tended to do so years later in life.
Further, the effects of in-utero rationing, alone, accounted for about one third of the lifetime risk reduction. For instance, even among the cohort born into a world without rationing, people who spent at least part of their gestation period under restrictions had a 15% lower lifetime risk of type 2 diabetes.
“Not only do you have to watch your baby’s sugar consumption, you have to watch your sugar consumption while pregnant,” says Robert Lustig, a pediatric neuroendocrinologist and member of the Institute for Health Policy Studies at University of California, San Francisco. Lustig was not involved in the new work, but notes the authors “did a very, very important service and a very good job.”
“What we found is, in one sense, not that surprising, because we already had a lot of knowledge about the association between sugar and poor health outcomes,” says Claire Boone, a study co-author and health economist at McGill University in Canada. “But the magnitude of our findings were kind of surprising,” she adds.
Heaps of past research has established links between high sugar intake and chronic illness. Yet the risk reductions in metabolic diseases associated with sugar rationing in early life are massive, on par with the effects of lifelong vegetarianism or quitting cigarettes. It goes to show that diet during a brief moment in one’s overall development can carry major consequences down the line.
“The most important takeaway is for parents,” says Paul Gertler, a study co-author and health economist at the University of California, Berkeley. The new findings are some of the only clear, causal human evidence of the value of following international and national guidance on sugar, he notes.
Guidelines from U.S. federal agencies say that infants and toddlers under two should not be given foods with added sugar, and that adults should limit their added sugar consumption to less than 10% of their overall calories. Recommendations from the American Heart Association are even more stringent. The AHA suggests that added sugar should make up less than 6% of total calories in a healthy diet, translating to an average of about 25g per day for women and 36g for men.
In reality, very few Americans manage to abide by these official suggestions, with U.S. adults eating 2-3 times the recommendation each day, on average. As a result, many people are born having been exposed to lots of sugar in the womb. Then, they continue to be exposed to foods with added sugar early on through formula and processed foods marketed to parents of infants and toddlers.
“We all want to improve our health and give our children the best start in life. Reducing added sugar early seems to be a powerful step in that direction,” says Tadeja Gračner, lead study author and an economist researching public health at the University of Southern California. Yet doing so can be really difficult in an environment where most processed and packaged foods contain added sugar, she acknowledges. “We don’t want to add yet another stressful item on the list for pregnant people,” Gračner says. “But it’s definitely information that we need to put out there–that this matters.”
To come to their findings, the study authors analyzed data from the UK Biobank, a database containing genetic, demographic, health, and lifestyle information on about 500,000 participants. They restricted their assessment to a short window encompassing those conceived on either side of the end of rationing, born between October 1951 and March 1956, to minimize broader societal and dietary changes over time (and to minimize any health effects of WWII itself). The rationed and unrationed cohorts used in the study were made up of about 38,000 and 22,000 people respectively.
“It doesn’t answer everything, but it is an econometric analysis, and it does infer causation,” says Lustig–which is hard to come by in long-term, human health studies. In other words, “it’s proof” of early sugar exposure’s impact on later-in-life illness, he says, where other research has only been able to offer correlations or links.
There are some limitations of the work. For one, the UK Biobank is not a perfectly representative group, and likely the participants represent a relatively wealthier, whiter slice of the population, says Boone. Overall calorie consumption did rise after food restrictions were lifted, so it’s impossible to entirely separate the effects of that change from the effects of sugar. “Calories were not kept constant,” says Gračner, but she and her colleagues did find that at least 77% of that increase in calories was from sugar, alone. And the research doesn’t firmly establish the mechanism by which early life sugar exposure increases disease risk.
However, the authors do have a hypothesis: It seems likely that sugar exposure early on predisposes someone to a lifetime of higher sugar consumption, says Gračner. Already, she and her colleagues have found evidence for this in some supporting, not-yet-peer-reviewed, analyses. Early follow-up research using data from the UK nutritional survey does indicate that people in the rationed cohort went on to eat less sugar (though approximately equal total calories) throughout their lives compared with their un-rationed peers. Therefore, the mechanism at play here doesn’t seem to be that 1,000 days of sugar exposure, alone, causes the observed health effects. Instead, “it’s something that kind of kicks you off on a different trajectory, with different behaviors,” she explains.
These findings will hopefully help inform personal decision-making, says Gertler, but also spur society-wide changes and regulations. “I think we need a public policy response to sugar the same way we had a public policy response to tobacco,” he says, including things like labeling laws, taxes, and advertising restrictions. He points to soda taxes as examples of legislation that have proven effective for lowering sugar consumption.
“We should also think about holding companies accountable,” adds Gračner. Perhaps, baby formula needs to be reformulated, she says.
Amid all the not-so-sweet news, though, there is a small silver lining (or candy-coating). “We don’t want to take away the joy of Halloween or other upcoming holidays. Birthday cake, candy, or whatnot in moderation won’t ruin our lives,” Gračner says. “It’s not about a piece of cake here or there. It’s about excessive intake of added sugar on a daily basis.”