The World Health Organization now recommends keeping sugar intake below 10% of daily energy consumption. Babies whose mothers had greater access to sugar during pregnancy ended up with lower body mass indexes (BMIs) as adults. A prenatal sugar bump may have made people thinner, smarter, and less sweet-toothed. Even more intriguingly, those genetically predisposed to crave sugar seemed to benefit more from the 1949 sugar surge. “In other words,” she says, “the high-sugar diet of 1949 helped these babies cope with the high-sugar world in which we now live.”She even floats a sweeter theory: maybe the treats helped mothers de-stress, boosting bonding and development.