Let‘s get serious about promoting physical activity

¹ From the University of Colorado Health Sciences Center, Denver.

See corresponding article on page 499.

² Address reprint requests to HR Wyatt, 4200 East 9th Avenue, Campus Box C225, Denver, CO 80262. E-mail: holly.wyatt{at}uchsc.edu.

Most health care professionals realize the urgent need to develop and implement strategies to combat the epidemic of obesity. One important first step is to prevent or slow the well-documented weight gain in the general population (1), but we also need to improve obesity treatment programs. The problem has been the perceived lack of successful strategies to either prevent or treat obesity. The article by Weinsier et al (2) in this issue of the Journal provides guidance for developing strategies to prevent weight gain or weight regain. Weinsier et al showed that the key factors that separate those who gain weight (gainers) from those who maintain weight (maintainers) over time are modifiable. Specifically, they showed that the maintainers had more muscle strength and engaged in more physical activity than did the gainers. The type of physical activity exerted by the maintainers appeared to be of relatively low intensity. This finding is important because this type of physical activity would be increased by efforts to increase activities of daily living such as walking or taking the stairs rather than by planned exercise. The obligatory metabolic rate—a less modifiable factor—did not differ significantly between the 2 groups. We believe that these results combined with the results of other studies showing the efficacy of physical activity in preventing weight gain or regain are sufficiently strong to stimulate a major public health effort to increase activities of daily living.

The study by Weinsier et al also has important implications for the treatment of obesity. Few obese individuals succeed in losing weight and maintaining that weight loss in the long term. Whether the success rate is the oft-quoted 5% or the 20% suggested by Wing and Hill (3), the fact is that we must get much better at weight management. How can we do this? It is really a problem of preventing weight regain, and again, the results of Weinsier et al are useful because some of the subjects in their study were previously obese. We already have a good ability to help our patients achieve weight loss, but we have a very poor ability to help our patients maintain that weight loss. We have generally considered weight loss and weight maintenance as a continuum in which the same strategies used to produce weight loss are expected to be effective in maintaining the weight loss and preventing weight regain. The results of this approach are consistent and well documented—patients reliably lose weight but fail to maintain the weight loss. The usual next step is to then examine how the weight-loss process can be changed to increase the likelihood that the weight loss will be maintained. Perhaps our challenge is not in finding better ways to lose weight so that it will be maintained but to treat weight loss and maintenance of weight loss as separate processes that require different strategies for success. The best diet and exercise plan for maintaining weight loss may be different from the best diet and exercise plan for losing weight. Again, an increase in activities of daily living appears to be an excellent strategy for preventing weight regain.

Weinsier et al suggest that promotion of more physical activity in the daily lives of the US population could be initiated as a public health strategy that would be effective at both preventing weight gain and weight regain after weight loss. Their findings add to a small but consistent body of literature showing that individuals engaging in high levels of physical activity have a greater chance of avoiding weight gain than do those with low levels of physical activity.

One of the issues not completely resolved in the study by Weinsier et al is whether it requires more physical activity to prevent weight regain than to prevent weight gain. In other words, do obese persons who lose weight (reduced obese) have to exert more effort to avoid weight gain than do persons who were never obese? Data from the National Weight Control Registry (4) and from Schoeller et al (5) suggest that the amount of physical activity required to prevent weight gain in reduced-obese individuals may be relatively high. The 2 groups in the study by Weinsier et al—the gainers and the maintainers—consisted of some subjects who had never been obese and some reduced-obese individuals who were trying to avoid weight regain. There were more reduced-obese individuals in the gainers group than in the maintainers group. It may be that these individuals require higher amounts of physical activity to overcome an extraordinary strong biological drive to regain lost body weight. Although most studies of reduced-obese individuals failed to find evidence of this (6, 7), some studies have suggested such a drive (8, 9). The available data (5, 6) suggest that the goal for physical activity for reduced-obese individuals to prevent weight regain should be much greater (at least double) than the 30 min/d suggested by the Surgeon General (10). Whether the amount of physical activity recommended to prevent weight gain in never-obese individuals needs to be increased is not clear.

It is time to get serious about combating obesity. The data are sufficiently strong to advocate promoting an increase in activities of daily living as a first strategy to prevent weight gain and regain. We must get the obesity community (ie, those interested in addressing the obesity epidemic, such as obese persons, physicians, dietitians, and insurance companies) to unite behind this strategy. Other strategies are certainly needed to combat obesity, but we must start somewhere and we must start now. It would be very helpful to understand the minimum amount of physical activity needed to prevent weight gain or to prevent weight regain in reduced-obese individuals and it would be wonderful to completely understand why physical activity is important in preventing weight gain. The greater immediate need is to devote resources to developing successful models for how to increase activities of daily living.

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