What’s the News: Researchers have known for decades that what a woman eats during her pregnancy can impact her child’s weight later in life. Now, a new study shows a possible mechanism for how mom’s diet affects baby’s weight: Epigenetic changes—changes that can increase or decrease the expression of a particular gene but don’t alter the genetic sequence—to a gene involved in fat metabolism can be passed from mother to child during pregnancy.

How the Heck:

The researchers asked nearly 80 pregnant women in Britain about their diets during pregnancy (and checked their blood for traces of some foods, to provide a more objective measure of diet).
At the birth of each child, the researchers took a sample of the child’s DNA from the umbilical cord. They analyzed the DNA for methylation, a common epigenetic change that occurs when a structure called a methyl group latches onto a particular point in a person’s DNA. When the children were nine years old, the researchers measured their body fat.
Children with methylation of a gene called RXR?, which is important in helping fat cells develop normally and in regulating their metabolism, were more likely to be obese than children ...