Beyond biology
We're used to thinking of obesity as a function of health behaviours like diet, physical activity, smoking, and alcohol intake. However, behaviours with obvious biological links don't explain everything about obesity. For example, obesity is associated with socioeconomic status in a predictable manner such that men with higher income are heavier and women with higher education are thinner. Social scientists like the University of Calgary's Dr. Lindsay McLaren are looking beyond biology to help explain these relationships.
In a recent study, Dr. McLaren examined time-use data from Statistics Canada over the past two decades and then related that information to what is known about the prevalence of obesity. For example, the time-use data show that higher-income men were more likely than lower-income men to spend time in paid work, commuting, and eating out and less likely to spend time sleeping. "This lifestyle profile may help explain why higher-income men are heavier than lower-income men," notes Dr. McLaren. "They may have higher stress levels; have less time for physical activity; eat food prepared outside the home, which tends to be higher in calories; and there is a biological link between sleep debt and obesity."
Interestingly, although high-income women have a similar lifestyle profile, they also spend more time on personal activities like grooming. Dr. McLaren speculates this lifestyle makes high-income men more prone to obesity but not high-income women because they are more concerned about their appearances and work hard to control their weights.
"To date, much of the research on obesity has focused on behaviours that are characterized as being a product of individual will," says Dr. McLaren. "This type of research takes a broader view of lifestyle, thereby drawing attention to the environment in which behaviours occur. In this way, I think we can gain new insights into the social determinants of weight and health."