摘要：In 2008, The Council of Australian Governments set a target to increase by 5% the proportion of Australian adults at a healthy body weight by 2017, over a 2009 baseline. Target setting is a critical component of public health policy for obesity prevention; however, there is currently no context within which to choose such targets. We analyzed the changes in current weight gain that would be required to meet Australian targets. By using transition-based multistate life tables to project obesity prevalence, we found that meeting national healthy weight targets by 2017 will require a 75% reduction in current 5-year weight gain. A reliable model of future body weight prevalence is critical to set, evaluate, and monitor national obesity targets. Many developed countries worldwide have set future targets on the prevalence of healthy weight, overweight, and obesity in an attempt to express their political will to tackle the obesity epidemic. An analysis of recent national targets in the United States and United Kingdom demonstrates that there has been no success in achieving these targets and, more importantly, there appears to be no apparent evidence base for the choice of target ( Table 1 ). TABLE 1 Past Obesity Targets in the United States and United Kingdom Country National Target Date Target Initiated Date to Achieve Target Strategy Achieved? United States Healthy People 2000 aims to reduce prevalence of overweight to no more than 20% of adults, from 24% in 1976–1980. 1 1990 2000 Decrease prevalence No United States Healthy People 2010 aims to increase percentage of healthy weight adults from 42% to 60% and decrease the prevalence of obese adults from 23% to 15%. 2 2000 2010 Decrease prevalence Noa United Kingdom Reduce percentage of obese men from 7% in 1986–1987 to 6% in 2005, and of obese women from 12% in 1986–1987 to 8% in 2005. 3 1992 2005 Decrease prevalence No United Kingdom Halt the year-on-year rise in obesity among children aged younger than 11 years to broadly tackle obesity in the population as a whole. 4 2004 2010 Decrease prevalence Nob Open in a separate window aProjections suggest these will not be met. bAbandoned in 2007. In 2008, The Council of Australian Governments set a target to increase by 5% the proportion of Australian adults at a healthy body weight by 2017, over a 2009 baseline. Healthy body weight refers to the normal weight category; no targets were set in reference to overweight and obese body weight categories. 5 This is a significant target, particularly as it is backed with financial support. However, there is currently no context within which to decide whether such a target is achievable, nor whether it is the best measure of successful obesity prevention. We, and others, have demonstrated that the prevalence of healthy weight is expected to plummet in the coming decade, 6 , 7 with a likely decrease among Australian adults from 35% in 2010 to 30% in 2020 if current trends persist (H. L. Walls, PhD, written communication, July 2010). In this context, even maintenance of current levels of healthy weight might be considered a marker of success. We are concerned that without realistic and practical obesity targets, the general public and the policymakers tasked with enacting these targets may become disillusioned and question our ability to tackle the current obesity epidemic. Insufficient public and political confidence will undermine the drive needed to address the current body weight trajectory. We analyzed what changes in current trends in weight gain would be required to meet the national government targets. In addition, we explored other possible targets that may more realistically reflect success in obesity prevention. To do this we used a transition-based multistate life table model, developed to project the prevalence of healthy weight, overweight, and obesity in adult Australians between 2005 and 2025. With this model we estimated the impact of hypothetical scenarios decreasing the degree of weight gain in the population on the future prevalence of healthy weight, overweight, and obesity.
