Growing Up Fat or Skinny in the Genes, Study Finds

WASHINGTON —  Heredity, rather than family life style during early childhood, is the dominant factor in determining whether a person becomes a fat adult, according to a definitive new study released Wednesday.

It has long been known that fatness runs in families, but also long debated has been whether it is the genes we inherit or the way we live--and eat--that make the most difference.

The conclusion in favor of heredity comes from a unique, large-scale survey of 540 adults in Denmark who had been adopted as infants. American and Danish researchers found a “strong relation” between how fat they were as adults and the size of their natural parents. But, to the scientists’ surprise, they found no such relationship to the degree of fatness of the adoptive parents with whom they had spent their childhood.

Family Environment

The team, headed by University of Pennsylvania obesity specialist Dr. Albert J. Stunkard, concluded that while “genetic influences are important determinants,” of body fatness, “childhood family environment alone has little or no effect.”

The strength of the findings may play a significant role in resolving the long-running “nature vs. nurture” debate about the relative importance of genetic and environmental contributions to obesity.

The study’s strong support of genetics “appears to resolve the controversy,” said Dr. Theodore B. Van Itallie, a Columbia University professor. “The study’s findings are unequivocal,” he wrote in an editorial in the New England Journal of Medicine, where the research was published today.