Children born in the years after World War II in Britain spent their early years under a food rationing regime that included sugar. According to The Guardian, adults received about 40 grams and children less than a tablespoon of sugar per day, and infants and toddlers were expected to receive very little or no added sugar. The restriction on sweets and chocolate was lifted in February 1953 and sugar rationing was ended in September that year, and by the second half of 1954 average sugar consumption had almost doubled. This sudden change has now allowed researchers to examine the consequences of low sugar consumption during the first 1,000 days of life.
According to The Guardian, the first study from the recent wave of research on sugar rationing used data from the UK Biobank to compare the health of people born shortly before and after the end of rationing. Some experienced rationing only during the prenatal period, some spent a few months or a few years after birth under the sugar rationing period, and a group born after rationing had not been exposed to the restriction at all.
The results of this review showed that the longer the exposure to the rationing period, the lower the risk of type 2 diabetes and high blood pressure in middle and older age. Those who spent the entire first 1,000 days of life in this period had a 35 percent lower likelihood of developing type 2 diabetes and a 20 percent lower likelihood of developing high blood pressure compared with those who were never exposed to rationing.
Subsequent studies observed associations between lower sugar consumption early in life and reduced risk of cardiovascular, liver and respiratory diseases, dementia, and some aging-related markers. One study found that people who were under rationing in childhood were about one year biologically younger on some markers.
Another study also found that those who spent the entire first 1,000 days of life in the rationing period had a 33 percent lower likelihood of being diagnosed with anxiety and decades later reported less inclination toward sweet foods.
It is still unclear exactly how lower sugar consumption in the early years can affect health decades later. Researchers say this effect may, in addition to forming habits and taste preferences in childhood, be related to changes in metabolism, insulin sensitivity, appetite regulation and satiety, and the development of adipose tissue.
New studies also suggest that a low-sugar diet early in life may reduce the effect of genes that predispose to weight gain. Researchers also point to a reduction in anxiety; the brain grows rapidly during the prenatal period and the early years of life and therefore may be more sensitive to the type of nutrition. On the other hand, high sugar consumption is associated with inflammation and changes in gut bacteria, both of which can affect brain function.
Research on the impact of prenatal and childhood nutrition has a long history. Studies of the Dutch "Hunger Winter" of 1944–1945 have shown that people exposed to severe famine in utero later had higher risks of overweight, obesity and type 2 diabetes. However, conditions in Britain were different; sugar rationing did not mean famine or severe calorie shortage and mainly limited sugar consumption, while the overall food supply was relatively adequate.
Researchers emphasize that the current studies do not prove causality and only show associations between sugar rationing and subsequent health outcomes. It is also not yet clear exactly how much sugar is too much or which stage of the first 1,000 days is most important. Evidence indicates that pregnancy is important and some associations become stronger when rationing continued beyond six months of age and the introduction of solid foods.
The amount of sugar consumed during British rationing roughly aligns with the country's current recommendations. Current guidelines recommend that added sugar consumption for adults and children aged over 11 be no more than 30 grams per day and be lower for younger age groups. It is also recommended that no sugar be added to infants' food and drink.