Weight status and perception barriers to healthy physical activity and ...

International Journal of Obesity (2008) 32, 343–352 & 2008 Nature Publishing Group All rights reserved 0307-0565/08 $30.00 www.nature.com/ijo

ORIGINAL ARTICLE Weight status and perception barriers to healthy physical activity and diet behavior E Atlantis1, EH Barnes2 and K Ball3 1 Exercise, Health and Performance Faculty Research Group, Faculty of Health Sciences, The University of Sydney, New South Wales, Australia; 2National Health and Medical Research Council, Clinical Trials Centre, The University of Sydney, New South Wales, Australia and 3Centre for Physical Activity and Nutrition (C-PAN), School of Exercise and Nutrition Sciences, Deakin University, Victoria, Australia

Background: Physical inactivity and insufficient fruit and vegetable consumption are key risk factors for obesity and noncommunicable diseases. Weight perceptions may affect physical activity and diet behaviors. We report current prevalence estimates of Australian adults meeting recommended levels of leisure-time physical activity (LTPA) (X150 min/week or more of at least moderate-intensity physical activity (including walking) on X5 days/week) and fruit (X2 servings/day) and vegetable (X5 servings/day) consumption for health benefits, by weight status and perceptions. Methods: We conducted a cross-sectional survey analysis of data for 16 314 adults from the Australian National Health Survey 2004–2005. All variables were collected by self-report. Weighted estimates were age- and gender-specific, and data were analyzed using logistic regression with acceptable weight referent categories, adjusting for covariates. Results: Among acceptable, overweight and obese adults, the prevalence of LTPA was 26.8, 26.1 and 19.3% for men, and 27.7, 23.7 and 19.7% for women, respectively. Approximately 55 and 15% of adults consumed sufficient fruit servings/day and vegetable servings/day, respectively, and less than 5% of adults met combined LTPA and diet guidelines. Overweight decreased the odds ratio for LTPA among women but not men, and obesity decreased the odds ratio for LTPA among both men and women. Overweight perception conferred odds ratios of 0.83 (95% CI 0.70–0.97, P ¼ 0.021) for overweight men, and of 0.74 (95% CI 0.62–0.88, P ¼ 0.001) and 0.69 (95% CI 0.59–0.80, Po0.001) for obese men and women, respectively; for LTPA, whereas no significant associations were found for acceptable weight perception. No consistent associations between weight status or perceptions and diet behaviors were found. Conclusions: Overweight perception may be another barrier to physical activity participation among men and women with excess body weight. Public health strategies might need to focus on overcoming weight perception as well as weight status barriers to adopting healthy physical activity behaviors. International Journal of Obesity (2008) 32, 343–352; doi:10.1038/sj.ijo.0803707; published online 7 August 2007 Keywords: weight perceptions; leisure-time physical activity; fruit; vegetable; overweight; prevalence

Introduction Overweight and obesity have increased over recent decades1–3 and are associated with increased noncommunicable disease and mortality burden throughout the world.4–11 Various factors are believed to affect energy expenditure and energy intake of individuals which account for overweight and obesity prevalence rates in populations.12,13 Low

Correspondence: Dr E Atlantis, School of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, PO Box 170, 75 East Street, Lidcombe, New South Wales 1825, Australia. E-mail: [email protected] Received 26 February 2007; revised 7 May 2007; accepted 1 July 2007; published online 7 August 2007

physical activity and insufficient fruit and vegetable consumption are also key risk factors for cardiovascular diseases.14–17 Thus, overweight adults are a high-risk subgroup of the general population for noncommunicable diseases. Population-based studies suggest that there are considerable misperceptions about the consequences of excess body weight among adults. For example, studies show that many overweight men and women perceive themselves as being in the acceptable weight range, and that this misperception is more common among men than women.18–20 In a statewide representative survey, when asked ‘Do you consider your weight as harmful to your health?’, over 60% of overweight men and over 40% of overweight women responded ‘Not at all’ or ‘Not very Harmful’.21 This survey

Weight/perception barriers to healthy behavior E Atlantis et al

344 also found that only 28% of overweight men and 41% of overweight women reported to be ‘Trying to lose weight’,21 similar to those of adults in other populations.19,22 These findings indicate that many overweight men and women have an acceptable weight self-perception and believe that their weight status is not hazardous to health, which may explain why many are not attempting weight-loss. Current theoretical models of weight-related behaviors such as physical activity and healthy eating emphasize, among other attributes, the importance of attitudes toward these behaviors. Social Cognitive Theory,23 for example, posits that a key psychological determinant of the decision to engage in physical activity/healthy eating is the individual’s ‘outcome expectation’, or the expected benefits and costs of performing a behavior. It might be hypothesized that, for those individuals who do not perceive themselves as overweight, there are fewer perceived benefits to engaging in regular physical activity or healthy eating, given the misperception that their weight is not problematic to their health and therefore there is no need for them to lose weight. It is not yet clear whether healthy physical activity and diet behaviors are more common among overweight adults with overweight perception than among overweight adults who misperceive that their weight is acceptable. Assuming the general population is aware that overweight is hazardous to health, we hypothesize that healthy physical activity and diet behavior may not differ between overweight adults who perceive themselves as overweight and acceptable (healthy) weight adults, whereas overweight adults who misperceive themselves as being acceptable weight might be less likely to meet healthy physical activity and diet guidelines than acceptable weight adults. In order to test this hypothesis, this study aimed to define the prevalence of meeting recommended levels of leisure-time physical activity (LTPA) and fruit and vegetable consumption among acceptable, overweight and obese adults, and overweight and obese adults who do and do not perceive themselves as overweight; and to investigate associated effects of weight status and perceptions.

Methods Sample We conducted a cross-sectional survey analysis of data from the Australian National Health Survey (NHS) 2004–2005; the most recent of a series of nationally representative surveys conducted by the Australian Bureau of Statistics. Information about health status, use of health services, healthrelated lifestyle factors, demographic and socio-economic characteristics of participants were obtained from residents of sampled private dwellings by trained interviewers. Private dwellings defined as homes, flats/units, caravans, tents and other structures being used as private places of residence were included when containing one or more person aged 18 International Journal of Obesity

years or over. The National Health Survey 2004–2005 response rate of 89% (19 501/21 808) was calculated by dividing the number of private dwelling units with fully completed interviews by the total number of sampled private dwelling units.24 There were data for 25 906 cases, of which 73% (19 018/25 906) were for adults aged 20 years or over. Body mass index (BMI) could not be derived for 9% (1747/ 19 018) of these adults due to missing data. Data were omitted for 427 adults with a BMI of less than 18.5 kg/m2 and for 530 adults (48 overweight and 15 obese adults) who perceived themselves as ‘underweight’. Complete data were available for the remaining 16 314 adults (7720 men, 8594 women) for analysis in this study.

Dependent variables Recommended leisure-time physical activity. LTPA data were derived from self-report duration and intensity of physical exercise (including walking) for recreation, sport or health/ fitness during the previous 2 weeks. Intensity of LTPA was determined by asking participants whether they did any exercise (apart from walking) that caused a moderate increase in their heart rate or breathing, and whether they did any vigorous exercise that caused a large increase in their heart rate or breathing. The questions and descriptors used in the NHS 2004–2005 to define physical activity duration, frequency and intensity are very similar to those of the International Physical Activity Questionnaire,25 which showed good repeatability coefficients and criterion validity for classifying those who achieved sufficient physical activity for health benefits compared with accelerometer methodology. Participants were also asked to estimate the total time they spent walking during the previous 2 weeks. Prevalence estimates of adults meeting recommended levels of LTPA for health benefits were determined using criteria in Australian national guidelines,26 consistent with American27 as well as international guidelines published by the World Health Organization.28 Adults who accumulated 150 min/week or more of at least moderate-intensity physical activity (including walking) on 5 or more days/week were defined as meeting recommended LTPA. Total time spent in vigorous physical activity was weighted by a factor of two to account for the increased metabolic cost of vigorous-intensity physical activities,29 which permitted the combining of total time spent in moderate-intensity physical activity with total time spent in vigorous-intensity physical activity, consistent with methodology used in previous studies, including the International Physical Activity Questionnaire validation study.25,30,31 Recommended diet. Daily fruit intake was assessed by asking participants ‘How many serves of fruit do you usually eat each day?’ including fresh, frozen and tinned fruit. Daily vegetable intake was assessed by asking participants ‘How many serves of vegetables do you usually eat each day?’ including fresh, frozen and tinned vegetables. A serving of


345 fruit was defined as ‘one medium piece or two small pieces of fruit, or one cup of diced fruit, or one quarter cup of sultanas or four dried apricots halvesFapproximately 150 g of fresh fruit or 50 g of dried fruits.’ A serving of vegetables was defined as ‘half a cup of cooked vegetables or one cup of salad vegetablesFapproximately equivalent to 75 g’. All types of vegetables were included except legumes, including tomatoes, as opposed to being counted as a fruit. Picture prompt cards as well as additional probing questions were used by interviewers to assist participants in accurately reporting the number of servings usually consumed per day. These short dietary questions were used in the Australian National Nutrition Survey32 in which they were shown to have good consistency across population subgroups for adequately discriminating between those with different fruit and vegetable consumption (1 serve or less, 2–3 serves and 4 serves or more) assessed against servings determined by 24-h recall.33 At least two fruit and five vegetable servings per day were used to define recommended diet behavior for health benefits, based on recommendations in the Australian Guide to Healthy Eating,34 also consistent with American guidelines35 and those of the World Health Organization for the prevention of noncommunicable diseases.36

conditions due to illness and injury or disability lasting or expected to last for at least 6 months).

Statistical analyses Statistical analyses were performed for men and women separately using SAS (version 8.02, SAS Institute Inc., Cary, NC, USA). Prevalence estimates and their standard errors were weighted to adjust for differences in the probabilities of selection among participants and to account for missing data due to nonresponse. Multivariate logistic regression models adjusting for all covariates were used to determine odds ratios (ORs) with 95% confidence intervals (CI) for meeting recommended levels of LTPA and fruit and vegetable consumption across overweight and obese compared with the acceptable weight category (referent); and across overweight self-perceived acceptable weight, and overweight self-perceived overweight subgroups compared with the acceptable weight category (referent). P-values of 0.05 or less were considered statistically significant for dependent variables. No adjustments were made for multiple comparisons.

Results Independent variables Body mass index. BMI was derived from self-report height and weight values. Standard (internationally used) BMI cut-offs were used to define underweight (o18.5 kg/m2), acceptable (healthy) weight (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2) and obesity (X30.0 kg/m2) categories. Weight perceptions. Data for self-perceived weight status were derived by asking participants, ‘Do you consider yourself to be acceptable weight, underweight or overweight?’ Overweight and obese participants were categorized into subgroups of those who self-perceived themselves as acceptable weight and those who self-perceived themselves as overweight.

Covariate variables Covariates include age (young 20–39 years, middle-aged 40– 59 years and elderly 60 years or over), level of highest postschool qualification including higher and bachelor degrees, postgraduate diploma and advanced diploma/certificate (yes/no or level not determined), weekly hours worked (not applicable because not employed and not looking for work, up to 34 h or X35 h), gross weekly personal cash income (not applicable or not reported, o$200, $200–$354, $355–$632, X$632), smoking status (current smoker, ex-regular smoker, never smoked regularly), general health self-assessment (excellent, very good, good, fair or poor), marital status (married/defacto relationship, single), number of long-term medical conditions (0–1, 2–3 and X4 current medical

Tables 1 and 2 show prevalence estimates for those meeting recommended levels of LTPA and fruit and vegetable consumption, as well as covariates among Australian men and women for 2004–2005, by weight status and perceptions. Obese men tended to show the lowest prevalence estimates for meeting recommended levels of LTPA, and fruit and vegetable consumption alone, and for meeting all guidelines combined (LTPA þ Diet) and the highest prevalence estimates for the following covariate categories: middle-aged (40–59 years), no/not determined post-school education, fair or poor general health assessment, married/ defacto-relationship and four or more long-term medical conditions. Obese women tended to show the lowest prevalence estimates for meeting recommended levels of LTPA, and fruit and vegetable consumption alone, and for meeting all guidelines combined (LTPA þ Diet) and the highest prevalence estimates for the following covariate categories: highest gross income (4$632), never smoked regularly, middle-aged (40–59 years) and elderly (X60 years), no/not determined post-school education, not employed and not looking for work (not applicable category for weekly hours worked category), fair or poor general health assessment, married/defacto relationship and four or more longterm medical conditions.

Overall effect of weight status and perceptions Tables 3–5 present the overall adjusted ORs for meeting recommended levels of LTPA and fruit and vegetable consumption by weight status and perceptions. Overweight among women decreased the OR for meeting recommended International Journal of Obesity

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International Journal of Obesity

Table 1

Prevalence of recommended LTPA and fruit and vegetable consumption, and covariates among Australian men for 2004–2005, by weight status and perceptions Prevalence estimates (% s.e.)a

Men (47.3%), X20 years

(N ¼ 7720)

Acceptable

Overweight (total)

(n ¼ 2646)

(n ¼ 3494)

Overweight (self-perceived acceptable weight) (n ¼ 2239)

Overweight (self-perceived overweight) (n ¼ 1255)

Obese (total) (n ¼ 1580)

Obese (self-perceived acceptable weight (n ¼ 308)

Obese (self-perceived overweight) (n ¼ 1272)

s.e.

%

s.e.

%

s.e.

%

s.e.

%

s.e.

%

s.e.

%

s.e.

LTPA X2 Fruit servings/day X5 Vegetable servings/day LTPAb+dietc

26.8 49.2 12.4 3.4

2.1 1.7 2.2 2.3

26.1 49.1 13.4 3.4

1.8 1.5 1.9 2.0

27.6 50.7 14.4 3.6

2.3 1.9 2.3 2.5

23.4 46.1 11.6 3.2

3.1 2.6 3.3 3.6

19.3 46.6 11.6 2.2

2.8 2.3 2.9 3.0

22.4 52.8 14.8 2.5

6.2 5.1 6.5 6.3

18.6 45.2 10.8 2.1

3.1 2.6 3.2 3.4

Age 20–39 years 40–59 years X60 years

45.3 31.4 23.3

1.9 2.0 2.1

38.0 40.0 22.0

1.7 1.6 1.8

40.6 37.8 21.6

2.1 2.1 2.2

33.3 43.9 22.8

2.9 2.6 2.9

31.9 47.9 20.1

2.6 2.3 2.7

35.9 42.0 22.1

6.1 5.3 5.9

31.0 49.3 19.7

2.9 2.5 3.0

Post-school educationd Yes No/not determined

59.5 40.5

1.6 1.9

58.8 41.2

1.3 1.6

56.6 43.4

1.7 2.0

62.7 37.3

2.1 2.8

53.4 46.6

2.1 2.3

49.8 50.2

5.0 5.2

54.2 45.8

2.3 2.6

Weekly hours worked Not applicablee 1–34 h/week X35 h/week

27.5 12.4 60.2

2.1 2.3 1.6

24.1 9.0 67.0

1.8 2.0 1.3

23.5 9.2 67.2

2.3 2.5 1.6

25.1 8.5 66.4

2.9 3.2 2.1

26.7 6.9 66.4

2.6 3.1 1.9

26.9 8.2 64.9

5.8 7.7 4.4

26.7 6.5 66.8

2.9 3.3 2.1

27.5

2.1

24.1

1.8

23.5

2.3

25.1

2.9

26.7

2.6

26.9

5.8

26.7

2.9

10.8 15.2 16.5 47.8

2.2 2.3 2.2 1.8

9.8 12.1 14.2 55.0

2.0 1.9 2.0 1.4

9.6 11.9 14.9 53.9

2.5 2.5 2.4 1.8

10.0 12.6 12.7 57.0

3.2 3.2 3.4 2.3

10.8 13.2 14.7 52.0

2.9 2.9 2.9 2.2

10.0 11.8 17.1 51.3

6.7 6.6 6.8 5.1

10.9 13.6 14.2 52.1

3.1 3.2 3.2 2.4

Smoking status Current smoker Ex-regular smoker Never smoked regularly

27.8 32.8 39.4

2.1 2.0 2.0

23.3 38.1 38.6

1.8 1.6 1.7

24.9 36.2 38.9

2.2 2.0 2.1

20.3 41.7 38.0

3.1 2.6 2.8

24.1 39.8 36.1

2.7 2.4 2.5

28.7 33.5 37.8

6.1 5.8 5.7

23.1 41.2 35.7

3.0 2.7 2.8

General health self-assessment Excellent Very good Good Fair or poor

26.7 34.2 26.0 13.1

2.1 2.0 2.1 2.3

18.0 37.0 29.6 15.3

1.9 1.7 1.8 1.9

21.1 37.8 27.1 14.0

2.3 2.1 2.3 2.4

12.4 35.5 34.4 17.7

3.2 2.9 2.8 3.1

7.9 30.5 36.0 25.5

3.1 2.6 2.5 2.7

13.3 36.7 32.6 17.3

7.2 5.6 6.1 6.1

6.7 29.1 36.8 27.4

3.4 2.9 2.7 3.0

57.0

1.6

67.9

1.2

67.2

1.6

69.2

2.0

69.7

1.9

65.9

4.3

70.5

2.0

43.0

1.9

32.1

1.8

32.8

2.2

30.8

3.0

30.3

2.7

34.1

6.1

29.5

2.9

No. of long-term medical conditionsf 0–1 39.6 2–3 30.7 X4 29.7

2.0 2.0 2.0

33.3 33.2 33.6

1.8 1.7 1.7

36.3 32.7 31.0

2.1 2.1 2.2

27.6 34.0 38.4

3.0 2.8 2.6

27.8 32.4 39.8

2.7 2.5 2.4

38.3 30.1 31.7

5.9 5.7 5.9

25.4 32.9 41.7

3.0 2.8 2.6

Gross income Not applicable/not reported o$200 $200–$354 $355–$632 4$632

Marital status Married/defacto relationship Single

Abbreviations: BMI, body mass index; LTPA, leisure-time physical activity. BMI derived from self-report height and weight values were used to define acceptable (18.5–24.9 kg/m2), overweight (25.0– 29.9 kg/m2) and obese (X30.0 kg/m2) categories. aPrevalence estimates were standardized using population person weights for age groups, also used to generate s.e. bAccumulated 150 min/week or more of at least moderate–intensity physical activity (including walking) on 5 or more days/week in the past 2 weeks. cConsumed X2 fruit servings/day and X5 vegetable servings/day in the past 2 weeks. d Includes postgraduate degree, graduate diploma/graduate certificate, bachelor degree, advance diploma/diploma or certificate. eNot applicable because not employed and not looking for work. fCurrent medical conditions due to illness, injury or disability lasting or expected to last for at least 6 months.


% b

Table 2

Prevalence of recommended LTPA and fruit and vegetable consumption, and covariates among Australian women for 2004–2005, by weight status and perceptions Prevalence estimates (% s.e.)a

Women (52.7%), X20 years

(N ¼ 8594)

Acceptable

Overweight (total)

(n ¼ 4354)

(n ¼ 2549)

Overweight (self-perceived acceptable weight) (n ¼ 1128)

Overweight (self-perceived overweight) (n ¼ 1421)

Obese (total) (n ¼ 1691)

Obese (self-perceived acceptable weight) (n ¼ 170)

Obese (self-perceived overweight) (n ¼ 1521)

%

s.e.

%

s.e.

%

s.e.

%

s.e.

%

s.e.

%

s.e.

%

s.e.

LTPA X2 Fruit servings/day X5 Vegetable servings/day LTPAb+dietc

27.7 59.9 16.1 4.4

1.6 1.2 1.7 1.8

23.7 62.8 18.1 4.2

2.2 1.5 2.2 2.3

24.7 61.9 17.5 4.3

3.3 2.3 3.3 3.5

23.0 63.4 18.5 4.0

3.0 2.0 2.9 3.1

19.7 62.1 18.3 3.5

2.8 1.9 2.9 3.1

23.7 59.5 18.6 5.0

8.7 6.3 10.0 9.3

19.2 62.4 18.2 3.4

2.9 2.0 3.0 3.3

Age 20–39 years 40–59 years X60 years

44.1 36.0 19.9

1.5 1.5 1.6

32.7 39.4 27.9

2.0 1.9 2.0

31.7 35.9 32.4

3.1 3.0 2.9

33.4 42.2 24.4

2.7 2.5 2.8

30.7 42.6 26.7

2.5 2.4 2.6

29.3 24.3 46.3

8.4 8.0 7.6

30.8 44.7 24.5

2.6 2.5 2.8

Post-school educationd Yes No/not determined

55.5 44.5

1.3 1.4

46.0 54.0

1.8 1.6

40.4 59.6

2.9 2.3

50.2 49.8

2.3 2.3

43.2 56.8

2.3 2.0

33.9 66.1

8.7 5.5

44.3 55.7

2.4 2.2

Weekly hours worked Not applicablee 1–34 h/week X35 h/week

38.9 28.3 32.7

1.5 1.6 1.6

46.0 24.6 29.4

1.8 2.1 2.1

47.5 24.0 28.4

2.6 3.3 3.1

44.8 25.0 30.2

2.4 2.7 2.8

48.1 24.1 27.8

2.2 2.7 2.7

66.8 20.9 12.3

5.4 9.5 10.6

45.9 24.5 29.6

2.3 2.8 2.7

b

38.9

1.5

46.0

1.8

47.5

2.6

44.8

2.4

48.1

2.2

66.8

5.4

45.9

2.3

16.7 18.8 21.0 28.9

1.7 1.6 1.7 1.6

20.2 23.9 19.0 25.9

2.1 2.1 2.3 2.1

21.9 24.9 18.3 24.3

3.2 3.2 3.4 3.2

18.9 23.1 19.6 27.1

2.8 2.8 3.1 2.8

20.9 24.5 20.4 23.0

2.7 2.7 2.8 2.7

25.5 35.4 19.2 9.9

8.9 7.9 9.3 9.4

20.4 23.3 20.6 24.5

2.8 2.8 2.9 2.9

Smoking status Current smoker Ex-regular smoker Never smoked regularly

19.8 24.2 56.0

1.7 1.6 1.3

19.9 26.8 53.3

2.2 2.1 1.7

18.3 24.3 57.4

3.4 3.2 2.5

21.2 28.7 50.1

2.9 2.7 2.3

18.3 31.4 50.4

2.8 2.5 2.2

18.0 25.6 56.3

9.3 8.3 6.6

18.3 32.0 49.7

2.9 2.6 2.3

General health self-assessment Excellent Very good Good Fair or poor

27.4 37.8 24.2 10.7

1.6 1.5 1.7 1.8

18.9 35.8 27.8 17.5

2.2 2.0 2.1 2.3

22.9 35.7 26.0 15.4

3.4 3.0 3.2 3.4

15.8 35.9 29.2 19.2

2.9 2.6 2.8 3.0

9.3 32.6 33.3 24.7

2.9 2.5 2.5 2.8

16.4 31.8 26.9 24.8

8.6 8.4 7.9 9.9

8.5 32.7 34.1 24.7

3.0 2.7 2.6 2.9

27.4 59.3

1.6 1.2

18.9 63.8

2.2 1.6

22.9 60.2

3.4 2.5

15.8 66.6

2.9 2.1

9.3 61.3

2.9 2.1

16.4 55.2

8.6 7.0

8.5 62.0

3.0 2.2

40.7

1.4

36.2

1.9

39.8

2.8

33.4

2.6

38.7

2.3

44.8

7.3

38.0

2.4

1.6 1.5 1.5

25.0 31.5 43.5

2.1 2.0 1.8

27.7 30.7 41.6

3.2 3.1 2.7

23.0 32.1 44.8

2.9 2.6 2.4

17.4 28.6 54.1

2.8 2.6 2.0

23.3 29.6 47.2

8.8 8.3 7.2

16.7 28.5 54.9

3.0 2.7 2.1

Marital status Married/defacto relationship Single


Gross income Not applicable/not reported o$200 $200–$354 $355–$632 4$632

f

Abbreviations: BMI, body mass index; LTPA, leisure-time physical activity. BMI derived from self-report height and weight values were used to define acceptable (18.5–24.9 kg/m2), overweight (25.0– 29.9 kg/m2) and obese (X30.0 kg/m2) categories. aPrevalence estimates were standardized using population person weights for age groups, also used to generate s.e. bAccumulated 150 min/week or more of at least moderate-intensity physical activity (including walking) on 5 or more days/week in the past 2 weeks. cConsumed X2 fruit servings/day and X5 vegetable servings/day in the past 2 weeks. d Includes postgraduate degree, graduate diploma/graduate certificate, bachelor degree, advance diploma/diploma or certificate. eNot applicable because not employed and not looking for work. fCurrent medical conditions due to illness, injury or disability lasting or expected to last for at least 6 months.

347


No. of long-term medical conditions 0–1 32.0 2–3 35.1 X4 32.9


348 Table 3 Odds of meeting recommended LTPA and fruit and vegetable consumption for overweight and obese compared to acceptable weight Australian men and women for 2004–2005, adjusted for all covariates Odds ratios with 95% CI Acceptable (referent)

Overweight OR

a

Obese

95% CI

P

OR

a

95% CI

P

Men, X20 years LTPAb X2 Fruit servings/day X5 Vegetable servings/day LTPAb+dietc

1.00 1.00 1.00 1.00

0.94 0.92 1.03 0.92

0.84–1.06 0.83–1.02 0.88–1.20 0.69–1.22

0.33 0.13 0.75 0.54

0.75 0.94 0.96 0.70

0.64–0.88 0.82–1.07 0.79–1.17 0.46–1.06

o0.001 0.34 0.70 0.09

Women, X20 years LTPAb X2 Fruit servings/day X5 Vegetable servings/day LTPAb+dietc

1.00 1.00 1.00 1.00

0.83 1.11 1.03 0.85

0.74–0.93 1.00–1.24 0.90–1.17 0.66–1.08

0.001 0.047 0.70 0.19

0.69 1.09 1.04 0.75

0.60–0.80 0.96–1.23 0.89–1.22 0.55–1.02

o0.001 0.17 0.60 0.07

Abbreviations: BMI, body mass index; CI, confidence interval; LTPA, leisure-time physical activity; OR, Odds ratio. BMI derived from self-report height and weight values were used to define acceptable (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2) and obese (X30.0 kg/m2) categories. aAdjusted for age, highest postschool qualification, weekly hours usually worked, gross weekly personal cash income, smoking status, general health self-assessment, marital status and number of long-term medical conditions. bAccumulated 150 min/week or more of at least moderate-intensity physical activity (including walking) on 5 or more days/week in the past 2 weeks. cConsumed X2 fruit servings/day and X5 vegetable servings/day in the past 2 weeks.

Table 4 Odds of meeting recommended LTPA and fruit and vegetable consumption for overweight self-perceived acceptable weight, and overweight selfperceived overweight compared to acceptable weight Australian men and women for 2004–2005, adjusted for all covariates Odds ratios with 95% CI Acceptable (referent)

Overweight (self-perceived acceptable weight)

Overweight (self-perceived overweight)

ORa

95% CI

P

ORa

95% CI

P


1.00 1.00 1.00 1.00

1.01 0.97 1.13 1.02

0.89–1.15 0.86–1.09 0.96–1.34 0.75–1.40

0.90 0.65 0.14 0.89

0.83 0.83 0.83 0.73

0.70–0.97 0.72–0.95 0.67–1.03 0.48–1.10

0.021 0.009 0.09 0.13


1.00 1.00 1.00 1.00

0.85 1.08 0.97 0.88

0.73–0.99 0.94–1.25 0.81–1.16 0.64–1.22

0.038 0.26 0.72 0.45

0.81 1.14 1.08 0.82

0.70–0.94 1.00–1.29 0.92–1.26 0.60–1.12

0.005 0.053 0.37 0.21

Abbreviations: BMI, body mass index; CI, confidence interval; LTPA, leisure-time physical activity; OR, Odds ratio. BMI derived from self-report height and weight values were used to define acceptable (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2) and obese (X30.0 kg/m2) categories. aAdjusted for age, highest postschool qualification, weekly hours usually worked, gross weekly personal cash income, smoking status, general health self-assessment, marital status and number of long-term medical conditions. bAccumulated 150 min/week or more of at least moderate-intensity physical activity (including walking) on 5 or more days/week in the past 2 weeks. cConsumed X2 fruit servings/day and X5 vegetable servings/day in the past 2 weeks.

levels of LTPA to 0.83 (95% CI 0.74–0.93, P ¼ 0.001) and increased the OR for sufficient fruit consumption to 1.11 (95% CI 1.00–1.24, P ¼ 0.047), whereas no effects were found among men. Obesity among men and women conferred ORs of 0.75 (95% CI 0.64–0.88, Po0.001) and 0.69 (95% CI 0.60– 0.80, Po0.001) for LTPA, respectively. These findings suggest that modest levels of excess body weight (BMI values 25.0– 29.9 kg/m2) are associated with insufficient physical activity levels among women only, whereas high levels of excess body weight (BMI values X30.0 kg/m2) are associated with insufficient physical activity levels among men and women. International Journal of Obesity

Overweight perception among overweight men decreased the odds for meeting recommended LTPA to 0.83 (95% CI 0.70–0.97, P ¼ 0.021) and for consuming sufficient fruit to 0.83 (95% CI 0.72–0.95, P ¼ 0.009), whereas no significant effects were found with acceptable weight perception. These findings suggest that overweight perception may be a more important barrier to healthy lifestyle behaviors than being overweight, among some men, given the lack of associations seen for overweight (Table 3), and the significant association seen for overweight perception among overweight men (Table 4). Contrary to findings for overweight men, we


349 Table 5 Odds of meeting recommended LTPA and fruit and vegetable consumption for obese self-perceived acceptable weight, and obese self-perceived overweight compared to acceptable weight Australian men and women for 2004–2005, adjusted for all covariates Odds ratios with 95% CI Acceptable (referent)

Obese (self-perceived acceptable weight) OR

a

Obese (self-perceived overweight)

95% CI

P

OR

a

95% CI

P


1.00 1.00 1.00 1.00

0.78 1.14 1.34 0.80

0.58, 1.04 0.89, 1.46 0.97, 1.87 0.38–1.67

0.09 0.30 0.08 0.55

0.74 0.89 0.86 0.66

0.62, 0.88 0.77, 1.02 0.69, 1.07 0.42–1.06

0.001 0.10 0.18 0.08


1.00 1.00 1.00 1.00

0.72 1.10 1.05 0.92

0.49, 1.06 0.79, 1.54 0.70, 1.58 0.42–1.99

0.09 0.56 0.81 0.82

0.69 1.09 1.04 0.73

0.59, 0.80 0.96, 1.24 0.89, 1.23 0.52–1.01

o0.001 0.20 0.62 0.06

Abbreviations: BMI, body mass index; CI, confidence interval; LTPA, leisure-time physical activity; OR, Odds ratio. BMI derived from self-report height and weight values were used to define acceptable (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2) and obese (X30.0 kg/m2) categories. aAdjusted for age, highest postschool qualification, weekly hours usually worked, gross weekly personal cash income, smoking status, general health self-assessment, marital status and number of long-term medical conditions. bAccumulated 150 min/week or more of at least moderate–intensity physical activity (including walking) on 5 or more days/week in the past 2 weeks. cConsumed X2 fruit servings/day and X5 vegetable servings/day in the past 2 weeks.

found no consistent associations between weight perception and ORs for meeting recommended levels of LTPA criteria and fruit and vegetable consumption among overweight women (Table 4). Rather, all overweight womenFboth those who perceived themselves as overweight and those who did notFwere less likely to meet recommended levels of LTPA than acceptable weight women. Overweight perception among obese men and women was most consistently associated with lower ORs for meeting recommended LTPA than was acceptable weight perception, compared with the acceptable weight category (referent). Overweight perception conferred ORs of 0.74 (95% CI 0.62– 0.88, P ¼ 0.001) and 0.69 (95% CI 0.59–0.80, Po0.001) for LTPA among obese men and women, respectively. Although acceptable weight perception among obese men and women also conferred decreased ORs for LTPA compared with acceptable weight men and women, greater variability was noted and associations were not statistically significant, in contrast to robust results found for overweight perception (Table 5).

Discussion This study reports the first prevalence estimates of meeting recommended levels of physical activity and fruit and vegetable consumption for health benefits, among Australian adults aged 20 years or older, by weight status and perceptions. Among acceptable, overweight and obese adults, the prevalence of those meeting LTPA criteria (X150 min/week of at least moderate-intensity LTPA on X5 days/week) was 26.8, 26.1 and 19.3% for men, and 27.7, 23.7 and 19.7% for women, respectively. Note that these

estimates are based on LTPA and are likely to underestimate the proportion of adults engaging in sufficient total physical activity for health benefits, given that these surveys to date have not assessed domestic and workplace-related physical activity. Nonetheless, our findings from the most recent available data suggest that most Australian adults across the weight spectrum are not meeting recommended levels of physical activity for health benefits, consistent with estimates published recently obtained from earlier Australian National Health Surveys30 and with estimates obtained from other populations.37,38 Low prevalence rates were also found for sufficient fruit and vegetable consumption. The prevalence of consuming sufficient fruit servings/day was 49.2, 49.1 and 46.6% among acceptable, overweight and obese men, and 59.9, 62.8 and 62.1% among acceptable, overweight and obese women. The prevalence of consuming sufficient vegetable servings/day was 12.4, 13.4 and 11.6% among acceptable, overweight and obese men, and 16.1, 18.1 and 18.3% among acceptable, overweight and obese women. Prevalence estimates for sufficient vegetable consumption for Australian women are far less than previously reported,39 which may be due to methodological differences between studies in assessment of vegetable intake, and to differences in age between the study cohorts. Most Australians are not consuming sufficient servings of fruits and vegetables for the prevention of cardiovascular events17,40 and total disease burden,41 and evidence for effective community-based interventions to address these shortfalls is lacking;42 highlighting important gaps in the published literature. Collectively, less than 5% of men and women met both LTPA and diet recommendations across acceptable, overweight and obese categories, largely due to a low prevalence for meeting sufficient vegetable consumption. Public health International Journal of Obesity


350 policy makers should be aware that approximately 95% of Australians may not be meeting physical activity and diet behavior guidelines for the prevention of noncommunicable diseases.13 Despite several methodological differences, similar low combined prevalence estimates (B15%) of sufficient physical activity and fruit and vegetable consumption for health benefits are also seen in the United States.43 Unless effective community-based interventions are developed and implemented promptly, the disease and impending economic burden of these combined risk factors on the general population will continue into the future.13 Overweight was significantly associated with decreased odds (17%) of meeting LTPA criteria and increased odds (11%) of consuming X2 fruit servings/day for women, but not for men. Obesity was significantly associated with decreased odds of meeting LTPA criteria for both men (25%) and women (31%). Thus, overweight and obesity in particular is associated with decreased odds of meeting recommended levels of LTPA for health benefits. However, the difference in prevalence estimates between acceptable weight and obese subgroups is small (B10%). Similar trends in prevalence estimates are seen in other countries.37,38 For example, the odds of meeting recommended levels of physical activity (performed during leisure-time, household chores and transportation) was significantly decreased among overweight women (23%), and obese men (32%) and women (47%) in the United States.37 Overweight seems to be associated with lower prevalence of sufficient physical activity but higher prevalence of sufficient fruit consumption among women only, whereas obesity is associated with lower prevalence of sufficient physical activity among men and women. Genetic,44 psychosocial45 and physiological as well as intrinsic motivational factors46 may explain why fewer overweight women and obese men and women meet recommended levels of LTPA compared with acceptable weight men and women. Overweight perception among overweight men was significantly associated with decreased odds of meeting LTPA (17%) and of consuming sufficient fruit servings/day (17%) compared with acceptable weight men. In contrast, no significant associations were found between acceptable weight perception and odds of meeting recommended LTPA and diet criteria. Among obese men and women, overweight perception was more consistently associated with decreased odds of meeting LTPA criteria than acceptable weight perception, compared with acceptable weight men and women. Results described above are contrary to our original hypothesis, based on one of the constructs of Social Cognitive TheoryF‘outcome expectancies’.23 However, these findings could partly be explained by another construct of Social Cognitive TheoryF‘behavioral capability’. That is, overweight perception among overweight/obese adults might be associated with the misperception of being incapable of engaging in healthy lifestyle behaviors, which might not be the case for acceptable weight perception among overweight/obese adults. Previous research has found International Journal of Obesity

that feeling ‘too fat to exercise’ among overweight men and women is a barrier to physical activity participation.45 Our findings extend this body of evidence, and suggest that overweight perception is a cognitive barrier to physical activity participation among men and women with excess body weight. If so, public health strategies promoting healthy physical activity and diet behaviors among overweight persons might need to focus on overcoming weight perception as well as weight status barriers. Alternatively, it is possible that these results are attributable to global misperceptions related to health. For example, overweight or obese persons who perceive themselves in an acceptable weight range may also be more likely to believe, and report, that they engage in healthy physical activity and diet behaviors. Future studies involving more objective measures of physical activity (for example, accelerometers to assess physical activity) and dietary intake (for example, multiple pass methodology47) might help confirm this hypothesis. Our findings also challenge the contemporary notion that, ‘recognising overweight is one step on the way to implementing changes in diet and physical activity; the next stage is trying to lose weight’,48 and highlight important distinctions between physical activity and diet behavior for weight-loss, and physical activity and diet behavior for health benefits. Although study strengths include the large, representative sample and the ability to control for numerous important covariates, several limitations should also be acknowledged. Inferences of results are limited to associations due to our cross-sectional study design and therefore well-designed prospective studies are needed to determine whether overweight perception is causally related to lowering the likelihood of meeting recommended levels of LTPA among those with excess body weight, compared to those in the healthy weight range. All variables were derived by self-report, which is less accurate than objective measures, and subject to selfselection bias. However, self-selection bias of participants with a specific interest in weight status and perceptions would be minimal in such a nationally representative survey which collected information on a range of topics.49 Finally, total time spent in, and frequency of, LTPA was averaged assuming equal distributions over 2 weeks. In summary, overweight and particularly obesity are associated with lower prevalence of sufficient physical activity for health benefits, but many of these associations are weakened by acceptable weight perception. Overweight perception may be another barrier to physical activity participation among men and women with excess body weight. No consistent associations between weight status or perceptions and diet behavior were found. Prospective studies are needed to determine whether overweight perception is causally related to lowering the likelihood of meeting recommended levels of physical activity among those with excess body weight, and if so, identify strategies for overcoming overweight perception as a barrier to adopting healthier physical activity behavior.


351

Acknowledgements Kylie Ball is supported by a NHMRC/NHFA Career Development Award.

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