Infants with big appetites: The role of a nonfood environment on infant appetitive traits linked to obesity.

Background: Individual differences in appetitive traits present in the first few weeks of life. Research has shown that infants with a greater food reinforcement ratio (FRR) have higher obesity risk. To date, limited work has examined the relation between FRR and appetitive traits of infants, and how FRR relates to appetitive traits and obesity development.

Objectives: To examine the relation between appetitive traits and food and nonfood reinforcement of infants aged 9-18 mo, and to examine whether food and nonfood reinforcement mediate the relation between appetitive traits and weight-for-length z-score (zWFL).

Method: This secondary data analysis was conducted by combining 4 different cohorts of infants (n = 143) who have complete data on the food/nonfood reinforcement task, Baby Eating Behavior Questionnaire, and anthropometrics and demographics assessments. Three different nonfood reinforcers were used: video (DVD; n = 27), playing with bubbles (Bubbles; n = 67), and music accompanied by instruments (Music; n = 49) for the nonfood portion of the task. For the food portion of the task, the infant's favorite food was used.

Results: General appetite positively correlated with FRR and zWFL, but negatively correlated with nonfood reinforcement; satiety responsiveness negatively correlated with food reinforcement, FRR, and zWFL. Mediational analysis showed that effects of general appetite on zWFL were mediated by FRR (indirect effect = 0.100, 95% CI: 0.041, 0.187) and nonfood reinforcement (indirect effect = 0.076, 95% CI: 0.025, 0.156). We also observed the mediating effect of FRR on the relation of satiety responsiveness and zWFL (indirect effect = -0.097, 95% CI: -0.204, -0.026).

Conclusions: Our work contributes to the mechanistic understanding of the ontogeny of obesity development early in life among individuals who are born with appetitive drive for overconsumption. During early infancy, the nonfood environment may protect against this drive and prevent obesity development.