A study of nearly 65,000 people born around World War II has revealed that the earliest chapters of a life — even those written before birth — may quietly determine the mind's fate decades later. By examining the United Kingdom's wartime sugar rationing as a natural experiment, researchers found that those who consumed less sugar in the womb and in infancy faced a 21–23% lower risk of dementia in old age, with the disease arriving, on average, 2.6 years later. The brain itself bore witness to this history: those with lower early-life sugar showed measurably more gray matter and less structural