Self-reported physical activity among South Carolina adults trying to maintain or lose weight.

Objectives: The obesity epidemic is related to widespread physical inactivity in the United States. This study determined the proportion of South Carolinians trying to maintain or lose weight and within that subpopulation, the number who practiced a restricted diet and engaged in physical activity.

Methods: Data from the 2002 South Carolina Behavioral Risk Factor Surveillance System survey were used to classify adults who were trying to maintain weight or lose weight. Self-reported prevalence of restricted diet and participation in physical activity were investigated. Of those who reported weight control practices, levels of physical activity were analyzed to determine if those trying to maintain weight or lose weight were meeting the national guidelines for moderate or vigorous physical activity.

Results: More than 70% of South Carolina adults reported trying to control their weight and the majority reported using physical activity for weight control. Though the majority reported use of restricted diet and physical activity, more than one-half of those individuals did not meet the minimum standards for physical activity designed for heart health.

Conclusions: Although most adults who are trying to maintain or lose weight are participating in physical activity, public health efforts need to focus on encouraging these adults to increase their levels of physical activity to meet the minimum standards for health benefits. Health care providers have an opportunity to educate and encourage patients about the recommended levels of physical activity to obtain maximum health benefits.

Key Words: national recommendations, physical activity, weight loss, weight maintenance

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The United States is facing two related epidemics: obesity and physical inactivity. (1) A recent report in the Journal of the American Medical Association quantified the leading causes of death in the United States and identified poor diet and physical inactivity as major contributing factors to mortality. Furthermore, poor diet and physical inactivity may soon surpass tobacco as the leading cause of death. (2) In the Surgeon General's Call to Action, it is stated that regular physical activity is imperative in the prevention of overweight and/or obesity. (3) The benefits of participation in regular physical activity are well known and widely documented. Participation in physical activity is protective against some obesity-related problems including gallstones, osteoarthritis, sleep apnea, and limitations to a healthy quality of life. (4)

Despite the known benefits of regular physical activity, many adults are not active at sufficient levels, and the prevalence of overweight and obesity are increasing at alarming rates. Results from a recent surveillance study indicate that an estimated 33% of the adult population in the United States is overweight and another 31% of US adults are obese. (5) In 2001, it was reported that 21.7% of adult South Carolinians were considered obese. (6) Recent research suggests that approximately 70 to 80% of adults are not active at levels sufficient to convey optimal health benefits. (7,8) The recommended guidelines set by the Centers for Disease Control and Prevention (CDC) and the American College of Sport Medicine (ACSM) state that all adults should accumulate at least 30 minutes of moderate-intensity physical activity on most and preferably all days of the week or 20 minutes of vigorous physical activity 3 days per week. (9)

The CDC reports 40% of US adults report not participating in any leisure time physical activity, and less than one third are meeting the minimum guidelines. (3) As physical activity is directly related to obesity and weight control through energy balance, physical activity and a healthy diet both play a significant role in the prevention of overweight and obesity.

The purposes of this study were to (1) identify the proportion of adults in South Carolina who report trying to maintain or lose weight, (2) determine the proportion of adults in South Carolina trying to maintain or lose weight who report using a restricted diet and physical activity for weight control, and (3) determine the proportion of adults who met the recommended levels of physical activity in their attempts to maintain or lose weight.

Materials and Methods

Data from the 2002 South Carolina Behavioral Risk Factor Surveillance System survey (BRFSS) were used. The BRFSS, which was developed by the CDC, is designed to evaluate preventive health and risk behaviors among adults in the United States aged 18 and older. Participants in South Carolina were contacted through the use of a randomized digit dialing procedure. A total of 3,173 respondents provided information about physical activity and answered the following questions, "Are you trying to lose weight?" and "Are you trying to maintain your current weight, that is, to keep from gaining weight?"

Respondents also reported whether or not they were using physical activity for weight control and if they had exercised or been physically active at least once in the past 30 days. Respondents were queried as to whether they engaged in moderate- and/or vigorous-intensity, nonoccupational leisure time physical activity during a typical week. They were also asked to report frequency (days per week) and duration (minutes per session) of these activities. Responses to these physical activity questions were used to stratify respondents to one of two groups: (1) meeting current CDC/ACSM physical activity recommendations (moderate intensity physical activity 30 minutes per day, 5 days per week and/or vigorous-intensity physical activity 20 minutes per day, 3 days per week) or (2) not meeting CDC/ACSM recommendations (inactive or engaging in some moderate- and/or vigorous-intensity physical activity but not meeting the recommendation). Though research has shown the recommendations to be sufficient for health benefits related to cardiovascular outcomes, the Institution of Medicine (IOM) has suggested that 30 minutes of physical activity may not be enough for weight control. The IOM suggests 60 minutes of moderate-intensity physical activity daily (IOM report) to prevent weight gain. (10) Therefore, those categorized as meeting CDC/ACSM recommendations were then classified further as either meeting or not meeting IOM suggestions of 60 minutes of at least moderate intensity physical activity a day.

To obtain information on dietary practices, respondents were asked if they were eating fewer calories, less fat, or both to lose weight or keep from gaining weight. If respondents reported eating fewer calories or less fat or both they were categorized as being on a restricted diet. Body mass index was categorized as lean (<24.9 kg/[m.sup.2]), overweight (25 to 29.9 kg/[m.sup.2]), and obese ([greater than or equal to]30 kg/[m.sup.2]). The difference in self-reported current and desired weight was calculated by subtracting desired weight from current weight.

To adjust for the individual sampling weights and the design effects of the BRFSS, SAS-SUDAAN (Research Triangle Institute, Research Triangle Park, NC) statistical software was used to perform all analyses. (11) Weighted proportions were computed for sex, body mass index, use of physical activity to maintain or lose weight, restricted diet, participation in physical activity in the past month, and level of physical activity for individuals trying to maintain weight and for individuals trying to lose weight. The proportion of respondents using physical activity for weight control was also stratified to determine if use of physical activity differed, depending on whether or not respondents were on a restricted diet. Finally, the prevalence of meeting CDC/ACSM physical activity recommendations for a health benefit was calculated for each weight control group.

Results

Characteristics of the respondents are presented in Table 1. In 2002, more than 70% of South Carolina adults reported trying to control their weight, with more reporting trying to lose weight than maintain their weight. About the same proportion of males and females reported trying to maintain weight; however, approximately 1.5 times more females than males reported trying to lose weight. As shown in Table 1, a higher percentage of respondents trying to lose weight reported using a restricted diet than those trying to maintain weight. More than 60% of respondents reported using physical activity for weight control in both weight maintenance and weight loss groups. The majority of respondents in both groups reported participating in exercise within the last 30 days. The data presented in Table 2 illustrate that the proportion of South Carolina adults using physical activity for weight maintenance was similar regardless of whether or not they were on a restricted diet. The same trend was true for those adults trying to lose weight.

As shown in Figure 1, 52% of individuals who reported trying to maintain weight and 57% reporting trying to lose weight did not meet the CDC/ACSM recommendations for physical activity. Therefore, although between 61% and 72% of individuals trying to maintain or lose weight reported using physical activity as a means of weight control; more than one half of those individuals did not meet minimum standards for physical activity designed for heart health. Among those meeting CDC/ACSM physical activity recommendations, only approximately 10% in either the weight maintenance or weight loss groups were physically active at levels suggested by the IOM for weight control.

[GRAPHIC OMITTED]

Discussion

Results revealed that well over one half of the South Carolina adults who participated in the survey reported using physical activity to maintain or lose weight, and yet more than 50% did not meet the minimum physical activity guidelines for general health benefits. Compared with the recommendation of 30 minutes per day of moderate intensity physical activity, the 1 hour per day of moderate physical activity suggested by the IOM offers added benefits for weight control. Exercising 1 hour per day positively changes body composition by decreasing body fat and increasing muscle mass, or both. (12-15) It is not surprising that only a small percentage (<10%) met the IOM suggestions, considering that approximately 50% of the adults trying to maintain or lose weight were obese. However, it is important to note that mortality rates are lower among individuals who are overweight or moderately obese and also physically fit compared with unfit individuals. This is important because physical activity positively affects several of the comorbid conditions of obesity. (16) For this reason, it is imperative for overweight and obese individuals to increase physical activity levels to reach the recommended guidelines set by the CDC/ACSM and gradually attain the IOM suggestions for weight control.

Interestingly, being on a restricted diet did not appear to affect participation in physical activity for the group of respondents trying to maintain or lose weight. More than one half of the respondents trying to maintain or lose weight reported participating in physical activity. For those people wishing to lose weight, it is recommended that they combine regular physical activity with a reduced caloric intake. (16) In addition, individuals who participate in multiple healthy behaviors (eg, maintain/lose weight, restricted diet, physical activity) should be advised on CDC/ACSM recommendations for physical activity to obtain maximum health benefits.

In 1989, the US Preventive Services Task Force implemented guidelines for physical activity counseling. (17) The recommended guidelines encouraged health care providers to counsel all patients to engage in regular physical activity that is personalized to their health status and lifestyle. (18) Some of the recommended guidelines include incorporating questions regarding physical activity levels of patients into history questions, guiding the patient in choosing appropriate types of physical activity, guiding the patient in choosing appropriate intensity, duration, and frequency of participation, monitoring compliance of physical activity, and providing reinforcing feedback during follow-up visits. (17) Incorporating these recommendations into routine client visits may also help increase the proportion of adults who participate in physical activity at levels that will maximize health benefits and help control weight.

Health care providers may also be able to encourage gender-specific activities to increase clients' enjoyment and ultimately promote lifelong participation in physical activity. (19) Results from a recent study that investigated preferences for types of physical activity revealed that men reported preferences toward walking, running, weightlifting, and golfing, whereas women reported preferences to walking, gardening, and aerobics classes. (19) Therefore, health care professionals who encourage regular walking could begin to increase the proportion of adults meeting the national guidelines, as well as facilitating lifelong behaviors.

The major limitation of this study is that the South Carolina BRFSS is a cross-sectional survey, and that the data collected are self-reported and may yield overestimations or underestimations of actual behavior. Despite this potential limitation, these data were population-based and collected by random selection, which allows for generalization. Also, for any health issue, it is important to determine the prevalence of relevant factors in the population. This study provides useful information on the prevalence of South Carolina adults trying to maintain or lose weight and, among those who report weight control, the prevalence of those not meeting the national recommendations for physical activity.

Conclusion

The 2002 South Carolina BRFSS showed that more than one half of those trying to maintain or lose weight are not meeting the recommended 30 minutes per day of moderate-intensity physical activity, which, in addition to aiding in weight control, is an essential component of a healthy lifestyle. Less than 10% are meeting IOM physical activity suggestions for weight control. Therefore, physicians and other health care professionals are encouraged not only to promote and advocate participation in regular physical activity but to emphasize specific recommendations for physical activity to maximize health outcomes, including achieving and maintaining a healthy weight.

Table 1. Characteristics of respondents by self-reported weight control
group

                             Trying to        Trying to lose
                             maintain weight  weight (%)
                             (%) n = 1,370    n = 1,803

Sex
  Male                       51.43            39.9
  Female                     48.57            60.1
Body mass index
  Lean weight                45.37            19.25
  Overweight                 40.44            38.17
  Obese                      14.19            42.58
Restricted diet
  Eating fewer calories      10.84            16.15
  Eating less fat            22.24            21.99
  Both                       31.46            51.36
Using physical activity for
    weight control
  Yes                        60.76            72.01
  No                         39.24            27.99
Participated in exercise
    and/or physical
    activity in past 30
    days
  Yes                        77.67            77.32
  No                         22.33            22.68
Mean difference between
    current weight and
    ideal weight
  Mean number of             10.67 (0.56)     32.49 (1.02)
    pounds (SE)

2002 Behavioral Risk Factor Surveillance System.

Table 2. Self-reported use of physical activity and restricted diet to
maintain or lose weight

                         Trying to        Trying to
                         maintain weight  lose weight
                         n = 1,346        n = 1,784

Restricted diet
  Physically active      62.09            73.83
  Not physically active  37.91            26.17
Unrestricted diet
  Physically active      57.66            60.09
  Not physically active  42.34            39.91

Smaller sample size due to exclusion of subjects who did not answer
questions about diet and physical activity. Data from 2002 Behavioral
Risk Factor Surveillance System.

Accepted September 1, 2004.

References

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RELATED ARTICLE: Key Points

* The majority of the people reporting an attempt to maintain weight or lose weight also report being physically active.

* Being on a restricted diet did not appear to affect participation in physical activity for the group of respondents trying to maintain or lose weight.

* More than 50% of individuals trying to maintain or lose weight did not meet the national guidelines for physical activity.

* Individuals who participate in multiple healthy behaviors (eg, maintain/lose weight, restricted diet, physical activity) should be advised on Centers for Disease Control and Prevention and the American College of Sport Medicine recommendations for physical activity to obtain maximum health benefits.

Diana L. Lattimore, MS, Heather R. Bowles, MS, Karen A. Kirtland, PHD, and Steven P. Hooker, PHD

From the Department of Exercise Science, the Department of Epidemiology and Biostatistics, and the Prevention Research Center, Norman J. Arnold School of Public Health, University of South Carolina, Columbia, SC.

Reprint requests to Dr. Steven P. Hooker, Prevention Research Center, 730 Devine Street, University of South Carolina, Columbia, SC 29208. Email: [e-mail]