Father and daughter

The children of parents who separate or divorce are more likely to become overweight than children whose parents stay together.

The article, published in Demography, found the body mass index (BMI) of children of separated parents is significantly higher in comparison to children whose families stay intact, with an especially strong association if the parents’ divorce occurs before the children reach the age of six. The findings support studies that have found parental separation is more detrimental if it occurs when the child is young.

The study used data from the UK Millennium Cohort Study, tracking the lives of 7,574 children born between 2000 and 2002, with the first data collected at around 9 months old and then at four stages (at ages 3, 5, 7, and 11). Within the sample, 1,573 children (approximately 20%) experienced parental separation. By monitoring the children over an extended period of their childhood, the study analysed the effects of divorce on physical health as a longer term process, rather than as comparison at a fixed point in time.

The research looked at the effect of parental separation on children as a process, analysing changes in their health before and after the date of their parents’ separation. The study only focused on the consequences of the first separation of children’s biological parents, excluding children whose biological parents separated and then reconciled, but not those children who experienced multiple separations. The authors controlled for other factors that could be associated with parental separation, such as socioeconomic disadvantage, and adjusted the BMI measures for age and gender, to take into account natural biological changes that occur as children grow older.

The results showed that on average, parental separation is positively and significantly associated with increases in BMI, and the effect of separation on child’s BMI tends to increase with time since separation.

BMI of the children of the separated parents becomes significantly higher 24 months after the separation in comparison to children whose parents stay together. The differences in the probability of children becoming overweight or obese became statistically significant 36 months after the separation.

The authors note that the effect of parental separation on children’s BMI becoming increasingly important two to three years after separation could be the consequence of a cumulative effect that occurs over time.

The authors add that their findings may not account for the full negative effects of parental separation, as the study focuses on children up to the age of 11, but not later. They write the results “underscore the importance of modelling parental separation as a process with potentially long-lasting consequences… The average effect might lead us to underestimate the association between parental separation and children’s weight trajectories because the magnitude of this association becomes stronger as the time since separation increases.”

This finding supports studies that show parental separation is negatively associated with children’s cognitive skills, educational outcomes, and emotional and psychological well-being.

The authors conclude that as the likelihood that children gain weight increases the longer the time since the separation, “efforts to prevent children at risk from gaining weight should start early and soon after separation. Intervening early could help to prevent—or at least attenuate—the process that leads some children to develop unhealthy obesity.”

Dr Berkay Özcan, Associate Professor from LSE's Department of Social Policy, said: “We show that the family context is crucially important for children’s health and we need policies that support children and families which are undergoing a break-up.

“Home-based interventions, welfare policies which increase resources for families and reduce the stress related to instability in the children’s environment may all help to prevent the onset of an unhealthy weight trajectory early on when a child is experiencing parental separation.”