| Research suggests that the high prevalence of obesity reflects substantial changes in our current food environment. However, it cannot be the sole risk factor as some individuals appear to be minimally affected by the 'obesogenic' environment. For example, many people in our society never become obese and others, if they do, are able to lose the excess weight and regain a healthy body size. Indeed, research has demonstrated that roughly 20 percent of overweight individuals are successful at this endeavour. While we now are starting to understand the general behaviours exhibited by successful weight loss maintainers, we still do not clearly know why those who are successful at maintaining their lost weight are able to engage in these behaviours on a long-term basis while many revert to their old habits. The goal of the present study was to examine biological, psychological, and behavioural factors associated with successful weight-loss maintenance. We investigated genetic markers for the mu-opioid receptors, measures of self-regulation and impulsivity, food preferences, and behaviours related to overeating in four groups of adults: a healthy-weight group, groups of obese adults with and without Binge Eating Disorder, and a group of previously obese individuals who have maintained significant weight loss through diet and exercise for a period of at least one year. Markers for the mu-opioid receptors were examined as these receptors have been found to be involved in rewarding aspects of feeding. Results indicated that the successful weight-loss group had lower levels of impulsivity, decreased preference for foods high in fat and foods high in both sugar and fat, as well as numerous eating behaviours related to overeating compared to the obese groups. Results of the current study, however, did not support the role of a genetic predisposition in the OPRM1 gene or the role of self-regulation in the long-term maintenance of body weight. |
