Restricted sugar intake during early life is linked to lower risks of several heart conditions in adulthood, includingheart attack,heart failure, andstroke, finds a study published by The BMJ today using data from the end of UK sugar rationing in 1953. The greatest protection against the risk of developing heart problems - and the longest delay in disease onset - was seen in people whose sugar intake was restricted from conception (“in utero”) to around 2 years of age. Evidence suggests that the first 1000 days of life (from conception to around 2 years of age) is a period when diet can have lasting health effects and leading health organisations recommend avoiding sugary drinks and ultra-processed foods (which often contain high amounts of sugar) as babies and toddlers are introduced to solids. Researchers therefore wanted to examine whether restricting sugar during this time is associated with a reduced risk of cardiovascular outcomes in adulthood. Using the end of UK sugar rationing in September 1953 as a natural experiment, they drew on data from 63,433 UK Biobank participants (average age 55 years) born between October 1951 and March 1956 with no history of heart disease. In total, the study included 40,063 participants exposed to sugar rationing and 23,370 who were not. Linked health records were then used to track rates of cardiovascular disease (CVD), heart attack, heart failure, irregular heart rhythm (atrial fibrillation), stroke, and cardiovascular death, adjusting for a range of genetic, environmental, and lifestyle factors. An external control group of non-UK born adults who did not experience sugar rationing or similar policy changes around 1953 were also assessed for more reliable comparisons. The results show that longer exposure to sugar rationing was associated with progressively lower cardiovascular risks in adulthood, partly due to reduced risks of diabetes and high blood pressure. Compared with people never exposed to rationing, those exposed in utero plus 1–2 years had a 20% reduced risk of CVD, as well as reduced risks of heart attack (25%), heart failure (26%), atrial fibrillation (24%), stroke (31%), and cardiovascular death (27%). People exposed to rationing in utero and during early life also showed progressively longer delays (up to two and a half years) in the age of onset of cardiovascular outcomes compared with those not exposed to rationing. Sugar rationing was also associated with small yet meaningful increases in healthy heart function compared with those never rationed. The authors point out that during the rationing period, sugar allowances for everyone, including pregnant women and children, were limited to under 40 g per day - and no added sugars were permitted for infants under 2 years old - restrictions consistent with modern dietary recommendations. This is an observational study so no firm conclusions can be drawn about cause and effect, and the authors acknowledge several limitations including a lack of detailed individual dietary data and potential recall bias that could have affected their results. However, they say this large, well-designed study allowed them to separately assess the effects of different exposure periods and explore the potential pathways linking sugar rationing and cardiovascular outcomes. As such, they conclude: “Our results underscore the cardiac benefit of early life policies focused on sugar rationing. Further studies should investigate individual level dietary exposures and consider the interplay between genetic, environmental, and lifestyle factors to develop more personalised prevention strategies.” Zheng J, Zhou Z, Huang J, Tu Q, Wu H, Yang Q et al. Exposure to sugar rationing in first 1000 days after conception and long term cardiovascular outcomes: natural experiment study BMJ 2025; 391 :e083890 doi:10.1136/bmj-2024-083890