Health & Medical Health & Medical

The Battle Against Obesity -- Attacking Physical Inactivity

´╗┐The Battle Against Obesity -- Attacking Physical Inactivity
Obesity is a comorbidity for some of the most prevalent chronic disease states, such as insulin resistance, type 2 diabetes mellitus and cardiovascular disease. The majority of patients with insulin resistance and type 2 diabetes mellitus are overweight, and up to 80% of them are obese. The positive relationship of obesity markers with major coronary risk factors is well documented. Furthermore, reductions in life expectancy as a result of obesity are staggering. For example, a 25-year-old man with morbid obesity has a 12-year decreased life expectancy when compared to an individual of healthy (rather than average) weight.

One of the best public-health approaches to combat the obesity epidemic would undoubtedly be to target strategies that prevent this condition in the first place (i.e. primary intervention). Instead, there have been calls for increased medical and surgical interventions to prevent and treat comorbidities (i.e. secondary and tertiary interventions). Of note, a rapid increase in the tertiary treatment of obesity-related disorders has been observed, particularly among young people, and the number of adolescent bariatric procedures performed in the US increased fivefold between 1997 and 2003. According to the American Society for Bariatric Surgery, diet, exercise, behavior modification, and drug interventions have all been ineffective in the treatment of morbid obesity in adults, with no indication that they are likely to be any more useful in the young. In this Viewpoint, however, we assert that primary prevention remains the way forward in our battle against this condition.

Primary prevention of obesity at the population level is a daunting challenge, particularly in the context of a modern society that has chosen to embrace a sedentary lifestyle in the face of an abundant food supply. The role of diet and nutritional factors as a cause of excess weight gain and obesity is outside the scope of this Viewpoint and is reviewed elsewhere. Nonetheless, it would be remiss not to acknowledge that nutritional risk factors, such as 'supersizing', changes in food composition and increased frequency of eating prepackaged food prepared outside the home, have all contributed to the increased prevalence of obesity in the US (and elsewhere).

Behavioral factors are clearly multifaceted, as demonstrated by the results of a study that suggested that obese and overweight children are highly responsive to television food advertising and that such advertisements specifically stimulate the intake of energy-dense snacks. Indeed, the interplay between behavioral, social and environmental influences is so complex that it is perhaps not surprising that many of the primary prevention strategies previously undertaken in our struggle against obesity have not enjoyed resounding success. One reaction to such a complex problem would be to simply throw our hands in the air and say "primary prevention measures are all too hard" and move on. However, the worldwide obesity epidemic is too rampant to even contemplate such a response.

We are the first to admit that we still have much to learn about how our modern, inactive lifestyle contributes to the obesity epidemic. The focus of the physical activity fraternity to date has been preventative in nature, with efforts largely concentrated on increasing organized, purposeful (usually leisure-time), formal exercise activities within the population. The results of several large-scale studies have demonstrated, however, that the majority of western populations fail to undertake sufficient structured exercise to attenuate weight gain, which indicates a need to explore alternative approaches. Results from our own research suggest that the vast majority of individuals need to place greater emphasis on their pattern of physical activity over the entire day, rather than just focusing on leisure-time exercise. Independent of the amount of leisure-time exercise undertaken, increased waist circumferences are observed in those individuals who spend large portions of the remainder of their day inactive (i.e. primarily sitting).

The implication of these findings is that the typical hour-long trip to the gym might not adequately compensate for the remaining time that we spend inactive. Evidence-based recommendations to reduce sedentary behavior (primarily sitting time) and accumulate greater amounts of body movement (energy expenditure) throughout the entire day by incidental activity need to be incorporated into future physical activity guidelines. For example, for the millions of sedentary office workers around the world, preventative strategies could focus on reducing the reliance on sitting, through the incorporation of regular, short, activity breaks or by redesigning workplaces to facilitate greater ambulation throughout the workday. An alarming prospect is that changes in technological environments at home, work and in the community, combined with the societal trends that contribute to the progression of human inactivity, show no signs of abating. In terms of inactivity, therefore, we might not yet have reached the nadir. The results from inactivity studies provide more evidence about the complex nature of obesity, and afford just one example to demonstrate that we have not yet exhausted all primary lifestyle prevention strategies to combat obesity. To simply shut up shop and say "we have tried everything" is clearly premature.

So, where do we go from here? To attack the growing health burden of obesity by investment in strategies that only target secondary and tertiary treatment is an admission that we might win individual battles on a few fronts, but we will ultimately lose the war. Moreover, emphasis on secondary and tertiary therapy is a case of too little and too late and will not succeed in reversing the tidal wave of obesity. Available funds to treat individuals with obesity are finite, whereas the number of people with the potential to become overweight and obese is infinite. We propose, therefore, that a greater emphasis be placed on implementation of primary prevention strategies to fight obesity. This approach means that we must tackle the environmental roots of this condition, namely our sedentary lifestyle and caloric excess. Primary defense mechanisms have the potential to decrease the prevalence of obesity by preventing the condition in the first place. Indeed, the health-care industry is paradoxical in that its principal goal should be to end health problems and human suffering and so put itself out of business.

In conclusion, weight-loss surgery for a relatively small number of individuals with obesity will undoubtedly save national health-care systems money in the short term. Nonetheless, the primary goals of the appropriate medical and legislative bodies should be promotion, long-term organization and support of supervised exercise and diet programs. These organizations should also aim to reduce sedentary time, provide better food labeling, ban 'junk food' advertisements during children's television programming, and promote increased education and awareness of the benefits of a healthy lifestyle. The results of many investigations have demonstrated that any single-intervention approach to treat obesity is unlikely to be effective over the long term. As such, further studies are urgently needed to determine the efficacy of prolonged, combination therapies for obesity on clinical, social and economic outcomes.

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