Infants with a hearty appetite grew more rapidly and might be genetically predisposed to obesity, according to two linked papers published Monday in the U.S. journal JAMA Pediatrics.

The first paper, by Professor Jane Wardle of University College London, England and colleagues, revealed that infants with a heartier appetite grew more rapidly up to age 15 months, potentially putting them at increased risk for obesity.

The authors used data from non-identical, same-sex twins born in the United Kingdom in 2007, who differed on questionnaires measuring appetite and satiety, and whose weight was measured from birth up to age 15 months.

Within pairs, the infant who was more food responsive or less satiety responsive grew faster than their co-twin, said the study. The more food responsive twin was 654 grams heavier than their co- twin at six months and 991 grams heavier at 15 months. The less satiety responsive twin was 637 gram heavier than their co-twin at six months and 918 grams heavier at 15 months.

"It might make life easy to have a baby with a hearty appetite, but as she grows up, parents may need to be alert for tendencies to be somewhat over-responsive to food cues in the environment, or somewhat unresponsive to fullness," said Wardle, lead author of the study. "This behavior could put her at risk of gaining weight faster than is good for her."

The second JAMA Pediatrics paper, in collaboration with King's College London, shed further light on the way that appetite, particularly low satiety responsiveness, acts as one of the mechanisms underlying genetic predisposition to obesity.

The researchers accessed data from 2,258 10-year-old children born in the United Kingdom between 1994 and 1996. The team used 28 obesity-related genes to create a polygenic obesity risk score ( PRS) for each child to estimate their genetic susceptibility to obesity. Higher PRS scores indicated a higher genetic predisposition to obesity.