Observing data on the body mass index (BMI) of children and their parents in the UK, US, China, Indonesia, Spain and Mexico, researchers found that parents account for up to 20% each (both mother and father) of factors causing obesity.
In other words, both the father and the mother are accountable for one fifth of a child’s BMI. The process of ‘intergenerational transmission’ of BMI rests on both genetic inheritance and the ‘household environment’ – meaning shared dietary and exercise habits, says the reportv
Previous research has well established the importance of parental habits and weight on the outcome of child health; a report by campaign group Early Nutrition last year found that parents obese at the time of conception and throughout pregnancy will triple the risk of having obese children.
Economic factors play little role
Researchers said the most substantial finding however was that rates of transmission for obesity remained constant throughout the six countries from which data was collected.
“We find that the intergenerational transmission of adiposity is remarkably constant and very comparable across time and countries – even if these countries are at very different stages in their economic development” the report read.
Factors such as economic development, industrialisation and employment have little impact on the degree to which obesity is inherited directly from parents.
The BMI of parents in Indonesia and the UK, both countries with substantially different social and economic environments, give equally accurate predictions for the likely BMI of their children.
Unfortunately, as the researchers point out, there is no way of determining what degree genetics and family environment play respectively in inheritance of obesity, but these factors combined play the most meaningful role.
Implications
According to the report, these findings reiterate the difficulty in reducing obesity through dietary interventions given the power of inheritance.
“Achieving weight reduction in the long term, for an obese individual, is both unlikely and extremely challenging” the report said.
However, dietitian Dr. Carrie Ruxton pointed out that whilst the influence of parents indeed makes change more unlikely, proper intervention is still necessary.
Talking to FoodNavigator, she said: “It is only the risk of obesity that is inherited – and this risk can be counterbalanced with an active lifestyle and good eating habits. Many children can ‘grow out’ of their obesity if parents take action early enough.
"This can include encouraging at least 60 minutes a day of active play and sport participation, limiting sedentary screen time to less than an hour a day, offering water or low fat milk instead of juices, cordials and fizzy drinks, providing child-appropriate portion sizes, limiting crisps, confectionery, cakes and biscuits to occasional treats, offering lower sugar breakfast cereals, and increasing [the] child’s intake of fruit, vegetables and wholegrain foods.”
Study: Economics and Human Biology
Published 2017, doi: http://dx.doi.org/10.1016/j.ehb.2016.11.005
"The intergenerational transmission of body mass index across countries"
Authors: Dr. Peter Dalton, Dr. Mimi Xiao et al.