Genetic insights into clock genes may influence childhood eating habits and obesity risk

A University of Guelph study reveals inherited differences in clock genes could shape young children’s eating patterns, highlighting a genetic factor in early obesity risk and the importance of sleep and routines.

A new study from the University of Guelph suggests that inherited differences in so-called clock genes may shape how young children eat, adding a genetic layer to the long-running debate over why some children gain weight more easily than others. Researchers found that certain variants were associated with higher energy intake and a lower share of protein in the diet among children aged 2 to 6, a pattern that could help explain early obesity risk.

The work, published in Nutrients in June, examined saliva samples from 168 children and looked for single-nucleotide polymorphisms, or SNPs, in eight genes involved in circadian rhythms, the body’s 24-hour biological clock. According to the study, one CRY2 variant was linked with an average of 118 extra calories a day, while a variant in NR1D1 was associated with a smaller proportion of calories coming from protein. The researchers said the findings point to a possible role for circadian biology in appetite and food choice.

David W.L. Ma, who led the University of Guelph team, said the results may eventually support more tailored approaches to childhood nutrition, including strategies that take sleep patterns into account. The university said the study is the first to examine clock-gene links to eating behaviour in children under 6. Ma said the work reinforces the importance of early routines around sleep and diet, though he also cautioned that parenting is demanding and that the goal is consistency over perfection.

Outside experts say the findings fit with a broader picture in which obesity is shaped by more than lifestyle alone. Kristen E. Boyle of the University of Colorado Anschutz, who was not involved in the study, said genetic factors, prenatal exposures, family environment and access to food can all influence eating habits from an early age. She said larger interventional studies would help clarify how these biological factors interact with diet over time.

The new paper builds on earlier research showing that circadian genes can affect metabolism and obesity risk in adults, but the Guelph team says more work is needed before the findings can be used in routine care. For now, the practical message is familiar: regular sleep and steady nutrition habits in early childhood may matter more than parents often realise.