Body weight rises as adults move from education into employment and parenthood

By Dr. Ananya Mandal, MDJan 20 2020

Being an adult is difficult as it is. Now two new reviews have shown that leaving school and getting employed as well as becoming a parent can lead to significant weight gain. The studies from researchers at the University of Cambridge were published in the Obesity Reviews.

The team of researchers from the Centre for Diet and Activity Research (CEDAR) at Cambridge, analyzed past studies that looked at the effects of leaving school, stating on higher education, getting a job, starting relationships and becoming a parent on weight gain and on general health. They explain that changes in diet and reduction in physical activity among other lifestyle changes are to blame for these changes.

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For these studies researchers had looked at the alterations in lifestyle behaviours and physical activity as individuals turned adults. The first study looked at the effect of leaving school on weight gain. The study was titled, “Changes in physical activity, diet, and body weight across the education and employment transitions of early adulthood: A systematic review and meta‐analysis.” For this study the team looked at six electronic databases for studies on the same research question. The changes in body weight and physical activity linked to life changes such as leaving high school, moving on to higher education/college or jobs etc. They scoured for studies from these databases up to July 2019. The changes were noted in persons aged between 15 and 35 years. A total of 19 studies were selected for the analysis. Of these 17 studies looked at the alterations in physical activity linked to life changes and three studies looked at the effects of these life transitions on body weight and five studies looked at the changes in diets and eating behaviours after life transitions.

Results from 9 studies revealed that leaving high school was associated with an average of around 7.04 minutes per day of reduction in moderate-to-vigorous physical activity. Men were more likely to fall prey to reduction in physical activity (average 16.4 minutes per day decrease) compared to women (average 6.7 minutes per day) wrote the researchers. Overall the levels of physical activity fell by an average of 11.4 minutes per day.

Three studies revealed that there was a significant rise in body weight after leaving high school for college or for a job. Two of the studies showed that with leaving high school the diet and eating behaviours also changed for the worse. One study showed that leaving university led to poorer diet choices and eating behaviours. They wrote, “leaving university was associated with increases of consumption of confectionery and sugar‐sweetened beverages, but starting employment was not associated with changes in diet quality.” Four studies showed that leaving university did not affect physical activity significantly but two studies showed that starting a job led to a reduction in daily physical activity. The team wrote, “The transition of leaving high school is an important time to support individuals to prevent decreases in physical activity and gains in body weight.”

These researchers concluded that there has been a focus on “school‐based public health policy and interventions,” but these studies reveal that obesity and overweight prevention should also focus on the transition period between school and college and university and employment. They also concluded that there are few studies that provide robust data on the effects of leaving high school on general health and more long term follow up studies are needed to understand the connection between leaving school and starting an employed life.

Lead author Dr Eleanor Winpenny from CEDAR and the MRC Epidemiology Unit at the University of Cambridge, said in a statement, “Children have a relatively protected environment, with healthy food and exercise encouraged within schools, but this evidence suggests that the pressures of university, employment and childcare drive changes in behaviour which are likely to be bad for long-term health.” She added, “This is a really important time when people are forming healthy or unhealthy habits that will continue through adult life. If we can pinpoint the factors in our adult lives which are driving unhealthy behaviours, we can then work to change them.”

The second study was titled, “Becoming a parent: A systematic review and meta‐analysis of changes in BMI, diet, and physical activity.” This study also looked at six different studies to see the effects on parenthood on the body mass index (BMI) of women. The participants were aged between 15 and 35 years. There were a total of 15 studies and six among them had only women participants.

Results revealed that there was a different in weight gain among women with and without children. Women who had not become mothers had an average gain of 2.8 points on their BMI over a period of 5.6 years on the average. This gain was an average of 12.3 percent from the baseline. Women who became mothers had an extra 0.47 points rise in their BMI. There was not changed in BMI for men who became fathers. Parents had a significant decline in their physical activity found the study compared to non-parents. Authors wrote, “Becoming a mother is associated with 17% greater absolute BMI gain than remaining childless.”

The team emphasized on focussing on BMI rise among young women (both mothers and non-mothers). Authors wrote in conclusion that more long term studies are needed to understand the connection between parenthood and poor lifestyle behaviours are needed.

Dr Kirsten Corder, from CEDAR and the MRC Epidemiology Unit, who led this study said, “BMI increases for women over young adulthood, particularly among those becoming a mother. However, new parents could also be particularly willing to change their behaviour as it may also positively influence their children, rather than solely improve their own health.” She added, “Interventions aimed at increasing parents' activity levels and improving diet could have benefits all round. We need to take a look at the messages given to new parents by health practitioners as previous studies have suggested widespread confusion among new mothers about acceptable pregnancy-related weight gain.”