Abstract
Objectives. We monitored changes in self-reported knowledge, attitudes, and behaviors regarding fruit and vegetable consumption in Western Australia prior to and after a healthful-eating campaign.
Methods. We obtained telephone survey data from 2854 adults in Perth from Nutrition Monitoring Surveys conducted in 1995, 1998, 2001, and 2004. The “Go for 2&5” fruit and vegetable campaign was implemented from 2002 to 2005.
Results. We observed changes in knowledge, attitudes, and behaviors regarding fruit and vegetable intake. In 2004, respondents were more likely than in 1995 to report 2 servings of fruit (odds ratio [OR] = 3.66; 95% confidence interval [CI] = 2.85, 4.70) and 5 servings of vegetables (OR = 4.50; 95% CI = 3.49, 5.80) per day as optimal. Despite this, vegetable consumption in 2004 was less than in 1995 (rate ratio = 0.88; 95% CI = 0.82, 0.96; P = .003). Perceived adequacy of vegetable (59.3%) or fruit (34.5%) intake and insufficient time for vegetable preparation (14.3%) were the main barriers.
Conclusions. Knowledge of the recommended fruit and vegetable intake increased following the Go for 2&5 campaign. Perceptions of the adequacy of current intake and time scarcity should be considered when designing nutrition interventions.
Culturally specific dietary guidelines have been developed to help citizens meet nutrient recommendations and reduce their risk of chronic disease. The Australian government's Dietary Guidelines provides culturally specific advice to the general public about healthful food choices and forms the basis for most nutrition education initiatives in Australia.1–3 Monitoring dietary factors that determine food consumption changes in relation to nutrition recommendations is necessary to assist in the development of public health interventions.4
Measuring the proportion of the population who meet dietary recommendations can assist in assessing the impact of health promotion initiatives.5 The routine data collected for health surveillance systems monitor health behavior trends and may be useful in providing feedback on the effectiveness of public health interventions. Monitoring attitudes and beliefs as well as self-reported dietary behaviors may provide useful insights about the factors associated with dietary patterns.
The public health focus on chronic disease prevention has led to an emphasis on increasing fruit and vegetable recommendations in dietary guidelines. Australian Dietary Guidelines1–3 advise people to “eat plenty of vegetables, legumes and fruits” and recommend that adults eat at least two 150-g servings of fruit and five 75-g servings of vegetables per day,6 a total of at least 675 g per day. This is consistent with the daily fruit and vegetable intake of 400 g to 600 g per day recommended by the World Health Organization, Food and Agriculture Organization of the United Nations, and the World Cancer Research Fund.7,8 It has been suggested that increasing consumer awareness of the recommended daily intake of fruits and vegetables for good health is a priority,9–12 because knowledge of recommended intake would in part determine an individual's ability to assess the adequacy of his or her current intake and need for change.9,13,14
In 2002, the Department of Health in Western Australia launched a high-profile social marketing campaign to increase consumer knowledge of recommended daily intakes of fruits and vegetables. The “Go for 2&5” message was that adults should eat 2 servings of fruits and 5 of vegetables every day.
The Department of Health in Western Australia conducted 4 Nutrition Monitoring Surveys of adults between 1995 and 2004. The purpose of the surveys was to provide information for planning initiatives to promote healthful eating behaviors consistent with the Dietary Guidelines for Australians. Respondents were queried about their knowledge, attitudes, and beliefs in relation to the Dietary Guidelines. The surveys also aimed to identify dietary concerns and barriers to, and promoters of, healthful eating behavior.
We describe the observed changes relating to fruit and vegetable intake among Western Australian adults residing in the Perth metropolitan area between 1995 and 2004.
METHODS
Surveys
Surveys were conducted during July and August 1995, 1998, 2001, and 2004. The sample for each survey was selected by computer-generated random-digit dialing, except in the 2004 survey, when the numbers were randomly selected from the electronic Perth metropolitan telephone directory to reduce the number of nonhousehold telephone numbers. Virtually all Australian households, more than 97.5%, had a telephone in 1999.15
Interviewing was conducted on weeknights and weekends over a 4-week period so the sample would not be biased against working people. The person aged 18 to 64 years with the next birthday within each household was selected. Up to 4 telephone calls were made to contact the required respondent—the initial call plus 3 callbacks—except in 2004 when up to 6 callbacks were made. No substitutions were made within households if the required respondent was not available.
From 1998 onward, to maintain gender balance, each survey was stratified according to gender with a predesignated ratio of male to female respondents of 1:1. The questionnaires contained between 107 and 120 defined category and open-ended questions. The questions relating to this study included the following:
Fruit and vegetable consumption.
“How many pieces of fruit did you eat yesterday? A piece of fruit would be, for example, an apple, a small bunch of grapes, 3 prunes, a quarter of rock melon, or half a cup of stewed, puréed, or canned fruit.”
“How many different types of vegetables did you eat yesterday? Include salads, fresh, frozen, canned, raw, and cooked vegetables.”
“How many cups of each type of vegetables did you eat? An example, 1 medium potato equals 1 cup of vegetables; include part cups,” and “Just to check … did you remember to include the salads, fresh, frozen, canned, raw, and cooked vegetables you ate yesterday?”
Dietary changes and barriers to increasing fruit and vegetables.
“In the past 12 months, have you tried to change the amount of fruit or vegetables that you eat?” If yes, “Was that an increase or a decrease?”
“What are the main things that make it difficult for you to eat plenty of fruit or more vegetables?”
Awareness of daily amount of fruit and vegetable recommendations.
“What do you think is the recommended number of servings of fruit that should be eaten each day? One serving of fruit is equal to 1 medium piece of fruit or half a cup of cooked or canned fruit.”
“What do you think is the recommended number of servings of vegetables that should be eaten each day? One serving of vegetables is equal to 1 medium potato, half a cup of cooked vegetables, or 1 cup of salad vegetables.”
Data on respondent's age, gender, highest level of education completed, country of birth, current employment status, occupation (job category), and total household income were also collected.
Statistical Analysis
We analyzed data with Stata software version 9.2 (StataCorp LP, College Station, TX). Before analysis, we weighted the samples with inverse probability weighting to match each sample to the Perth metropolitan age and gender population estimates according to Australian Bureau of Statistics Census data for the appropriate year.16 We calculated prevalence estimates and means with Stata software's suite of survey estimation commands (SVY) for sample surveys.
We assessed binary outcomes with the svy commands for binary logistic regression and reported them as odds ratios (ORs) with 95% confidence intervals (CIs). We assessed count outcomes with either the SVY Poisson or negative binomial regression models as appropriate for the best model fit and reported them as incidence rate ratios (RRs) with 95% CIs.
We reported associations between each outcome variable in 1995 and other years in which the survey was conducted with adjustment for age and gender. The additional effects of level of education and household income were also included in the models and kept when significant (P < .05) according to the Wald statistic.
RESULTS
The final samples of 600 to 753 persons per survey represented between 32% and 58% of the total contacts made. This is a typical response rate for this type of survey.17,18 This sample size is sufficient to obtain estimates of proportions with 95% CIs accurate to ±3.8% (n = 750) to ±4% (n = 600). The reason for exclusion of contacts in this survey included language or hearing problems, being outside the age range, being unavailable for the duration of the survey, or refusal to participate. Table 1 displays the participation rates and demographics of the participants for each year. The average interview took between 33 and 35 minutes.
TABLE 1.
Sample Demographics, by Nutrition Monitoring Survey Year: Western Australia, 1995–2004
| 1995 | 1998 | 2001 | 2004 | |
| Participation rate,a % | 34 | 32 | 33 | 58 |
| Reasons for nonparticipation | ||||
| Hearing loss, language, or age range, % | 7 | 2 | 6 | 20 |
| Refusal, not available for duration, % | 14 | 8 | 20 | 15 |
| Terminations, % | < 1 | < 1 | < 1 | < 1 |
| Gender | ||||
| Men, no. (%) | 274 (37) | 375 (50) | 405 (54) | 300 (50) |
| Women, no. (%) | 474 (63) | 376 (50) | 349 (46) | 301 (50) |
| Total, no. | 748 | 751 | 754 | 601 |
| Education | ||||
| Year 10, junior achievement certificate, no. (%) | 248 (33) | 235 (31) | 210 (28) | 117 (20) |
| Year 12, certificate secondary education, no. (%) | 194 (26) | 187 (25) | 210 (28) | 137 (24) |
| University degree, no. (%) | 238 (32) | 251 (34) | 264 (36) | 245 (42) |
| Apprenticeship or trade qualification, no. (%) | 67 (9) | 78 (10) | 62 (8) | 81 (14) |
| Total, no. | 747 | 751 | 746 | 580 |
| Income, Aus $, no. (%) | ||||
| < 15 000 | 81 (11) | 64 (9) | 61 (9) | 28 (5) |
| 15 000–34 999 | 239 (34) | 185 (26) | 147 (21) | 103 (18) |
| 35 000–50 000 | 188 (26) | 151 (21) | 125 (17) | 98 (17) |
| > 50 000 | 206 (29) | 317 (44) | 376 (53) | 352 (60) |
| Total | 714 (100) | 717 (100) | 709 (100) | 581 (100) |
| Age category, y, no. (%) | ||||
| 18–19 | 30 (4) | 17 (2) | 28 (4) | 16 (3) |
| 20–24 | 55 (7) | 67 (9) | 61 (8) | 51 (8) |
| 25–29 | 74 (10) | 63 (8) | 71 (9) | 59 (10) |
| 30–34 | 111 (15) | 90 (12) | 99 (13) | 64 (11) |
| 35–39 | 111 (15) | 109 (15) | 101 (13) | 61 (10) |
| 40–44 | 105 (14) | 121 (16) | 128 (17) | 78 (13) |
| 45–49 | 98 (13) | 103 (14) | 81 (11) | 64 (11) |
| 50–54 | 62 (8) | 74 (10) | 85 (11) | 72 (12) |
| 55–59 | 49 (7) | 55 (7) | 58 (8) | 91 (15) |
| 60–64 | 53 (7) | 52 (7) | 42 (6) | 45 (7) |
| Total | 748 (100) | 751 (100) | 754 (100) | 601 (100) |
Participation rate = completed interviews divided by (completed interviews + refusals + terminations).
Knowledge of Recommended Intakes of Fruit and Vegetables
Table 2 displays participants' knowledge of the recommended intakes of fruit and vegetables between 1995 and 2004. The proportion correctly reporting the minimum recommended 2 servings of fruit daily increased from 23.8% in 1995 to 52.7% in 2004. In 2004, respondents were several times more likely to say they should eat 2 servings of fruit per day than they were in 1995 (OR = 3.66; 95% CI = 2.85, 4.70; P < .001). There was no significant difference in the proportion of women and men correctly identifying the minimum recommended fruit intake.
TABLE 2.
Knowledge of Recommended Number of Servings of Fruit and Vegetables per Day and Beliefs About Diet: Nutrition Monitoring Surveys, Western Australia, 1995–2004
| 1995 (n = 748) |
1998 (n = 751) |
2001 (n = 753) |
2004 (n = 601) |
|||||||||
| % | OR (95% CI) | P | % | OR (95% CI) | P | % | OR (95% CI) | P | % | OR (95% CI) | P | |
| Servings of fruit recommended per daya | 1.00 (Ref) | NA | 1.01 (0.78, 1.29) | .955 | 1.36 (1.06, 1.73) | .015 | 3.66 (2.85, 4.70) | <.001 | ||||
| 1 | 8.6 | 4 | 5.3 | 3.7 | ||||||||
| 2 | 23.8 | 23.8 | 29.4 | 52.7 | ||||||||
| ≥ 3 | 60.5 | 66.5 | 59.6 | 40.2 | ||||||||
| Other | 1.3 | 0.3 | 0.7 | 0 | ||||||||
| Don't know | 5.8 | 5.2 | 5 | 3.3 | ||||||||
| Servings of vegetables recommended per dayb | 1.00 (Ref) | NA | 1.12 (0.88, 1.43) | .344 | 1.25 (0.99, 1.58) | .064 | 4.50 (3.49, 5.80) | <.001 | ||||
| 1 | 7.6 | 3.7 | 3.3 | 0.8 | ||||||||
| 2 | 12.9 | 9.5 | 10.1 | 4.5 | ||||||||
| 3 | 27 | 29 | 26.4 | 17.1 | ||||||||
| 4 | 18.6 | 20 | 17.4 | 11 | ||||||||
| 5 | 30.1 | 32.4 | 34.8 | 64.3 | ||||||||
| ≥ 6 | 3.9 | 5.4 | 8 | 2.4 | ||||||||
| Tried changing amount of fruit eaten in past 12 monthsc | 1.00 (Ref) | NA | 1.00 (0.80, 1.25) | .978 | 0.89 (0.72, 1.12) | .324 | 1.08 (0.86, 1.37) | .496 | ||||
| Increased | 39.4 | 39.3 | 36.2 | 40.7 | ||||||||
| Decreased | 2 | 1.1 | 2 | 3.4 | ||||||||
| Not tried | 58.6 | 59.7 | 62.8 | 55.9 | ||||||||
| Tried changing amount of vegetables eaten in past 12 monthsd | 1.00 (Ref) | NA | 0.86 (0.68, 1.10) | .232 | 0.86 (0.67, 1.09) | .207 | 1.09 (0.85, 1.41) | .496 | ||||
| Increased | 33.8 | 30.5 | 29.3 | 33.5 | ||||||||
| Decreased | 1.4 | 0.7 | 0.2 | 0.5 | ||||||||
| Not tried | 64.9 | 68.9 | 70.6 | 66.4 | ||||||||
Note. OR = odds ratio; CI = confidence interval; NA = not applicable. Percentages are sample weighted.
ORs, 95% CIs, and P values for correctly answering minimum intake of 2 servings of fruit per day compared with 1995. Effect estimates were adjusted for 5-year age group and gender.
ORs, 95% CIs, and P values for correctly answering minimum intake of 5 servings of vegetables per day compared with 1995. Effect estimates were adjusted for 5-year age group and gender.
ORs, 95% CIs, and P values for changes to fruit intake in the past 12 months. Effect estimates were adjusted for 5-year age group, gender, and income.
ORs, 95% CIs, and P values for changes to vegetable intake in the past 12 months. Effect estimates were adjusted for 5-year age group, gender, and income.
The proportion of respondents reporting the minimum recommended 5 servings of vegetables a day increased from 30.1% in 1995 to 64.3% in 2004. In 2004, respondents were more than 4 times more likely to know the minimum recommended 5 servings of vegetables than they were in 1995 (OR = 4.50; 95% CI = 3.49, 5.80; P < .001). Overall, women were more likely than were men to know the minimum recommended intake of vegetables (OR = 2.49; 95% CI = 2.09, 2.96; P < .001).
Attempts to Increase Fruit and Vegetable Consumption Over the Past Year
Table 2 displays respondents' attempts between 1995 and 2004 to change their fruit and vegetable intake in the previous year. There were slight changes across the surveys in the proportion of respondents who had tried to increase their fruit intake over the past year: 39.4% in 1995, 39.3% in 1998, 36.2% in 2001, and 40.7% in 2004 (design-based F5.9, 16 833.5 = 2.11; P = .05). Overall, women were more likely than were men to have attempted to increase their fruit intake (OR = 1.31; 95% CI = 1.12, 1.54; P < .001), and attempts to increase intake decreased with increasing age (OR = 0.91; 95% CI = 0.88, 0.94; P < .001; data not shown).
Only about one third of respondents had tried to increase their vegetable intake over the previous year: 33.8% in 1995, 30.5% in 1998, 29.3% in 2001, and 33.5% in 2004 (design-based F5.91, 16 848.3 = 2.74; P = .01). Overall, women were more likely to have attempted to increase their vegetable intake than were men (OR = 1.81; 95% CI = 1.52, 2.17; P < .001), and attempts to increase intake decreased with increasing age (OR = 0.91; 95% CI = 0.88, 0.95; P < .001) and increasing income (OR = 0.90; 95% CI = 0.82, 0.98; P < .019; data not shown).
Fruit and Vegetable Intake on the Day Before the Survey
Table 3 displays fruit and vegetable consumption on the day before the survey between 1995 and 2004. There were no significant changes in mean fruit consumption between 1995 and 2004. Overall, women ate 20% more pieces of fruit than did men on the day before the survey (RR = 1.20; 95% CI = 1.09, 1.32; P < .001), those with higher education ate more pieces (RR = 1.11; 95% CI = 1.06, 1.17; P < .001), and intake was higher with increasing income (RR = 1.06; 95% CI = 1.00, 1.11; P = .036; data not shown).
TABLE 3.
Self-Reported Fruit and Vegetable Consumption on Day Before Nutrition Monitoring Survey: Western Australia, 1995–2004
| 1995 (n = 748) |
1998 (n = 751) |
2001 (n = 753) |
2004 (n = 601) |
|||||||||
| % or Mean (95% CI) | RR (95% CI) | P | % or Mean (95% CI) | RR (95% CI) | P | % or Mean (95% CI) | RR (95% CI) | P | % or Mean (95% CI) | RR (95% CI) | P | |
| No. of pieces of fruit eaten on day before survey | 1.00 (Ref) | NA | 1.08 (0.99, 1.18) | .098 | 0.95 (0.87, 1.04) | .304 | 0.97 (0.89, 1.06) | .483 | ||||
| None | 23 | 21 | 26.3 | 20.3 | ||||||||
| 1 | 21 | 19.7 | 17.3 | 20.9 | ||||||||
| 2 | 23.4 | 26.2 | 25.6 | 30.2 | ||||||||
| 3 | 16.8 | 15.3 | 18 | 17.3 | ||||||||
| 4 | 10.7 | 8.6 | 7.4 | 7.4 | ||||||||
| 5 | 2.4 | 4.2 | 3.3 | 2.8 | ||||||||
| 6 | 2.7 | 5.1 | 2 | 1.1 | ||||||||
| Mean pieces consumed | 1.94 (1.81, 2.07) | 2.14 (1.98, 2.30) | 1.85 (1.73, 1.97) | 1.85 (1.72, 1.97) | ||||||||
| Consumed fruit on day before the surveya | 1.00 (Ref) | NA | 0.85 (0.58, 1.24) | .405 | 0.60 (0.41, 0.86) | .006 | 0.86 (0.56, 1.32) | .5 | ||||
| No. of vegetables eaten on day before survey, cups | 1.00 (Ref) | NA | 0.94 (0.87, 1.01) | .08 | 0.95 (0.88, 1.02) | .179 | 0.88 (0.82, 0.96) | .003 | ||||
| 0 | 9 | 11.4 | 14.4 | 16.1 | ||||||||
| 1 | 19.8 | 21.6 | 19.7 | 24.2 | ||||||||
| 2 | 27.4 | 28.5 | 24.1 | 24.4 | ||||||||
| 3 | 20 | 17.9 | 19.1 | 14 | ||||||||
| 4 | 12.4 | 8.9 | 9.8 | 8.5 | ||||||||
| 5 | 4.9 | 6.1 | 6.1 | 6.7 | ||||||||
| 6 | 6.5 | 5.7 | 6.8 | 6.1 | ||||||||
| Mean cups consumed | 2.81 (2.67, 2.95) | 2.70 (2.56, 2.83) | 2.72 (2.57, 2.86) | 2.55 (2.40, 2.71) | ||||||||
| Consumed vegetables on day before surveya | 1.00 (Ref) | NA | 0.76 (0.48, 1.03) | .074 | 0.47 (0.33, 0.68) | <.001 | 0.47 (0.32, 0.68) | <.001 | ||||
| No. of different types of vegetables eaten on day before survey | 1.00 | NA | 1.03 (0.98, 1.08) | .283 | 0.85 (0.80, 0.90) | <.001 | 0.93 (0.88, 0.98) | .009 | ||||
| 0 | 6 | 5.7 | 11.2 | 8.8 | ||||||||
| 1 | 5.4 | 3.5 | 8.5 | 3.6 | ||||||||
| 2 | 8.2 | 8.3 | 13.1 | 12.6 | ||||||||
| 3 | 19.3 | 18.3 | 20.1 | 17.9 | ||||||||
| 4 | 21.6 | 22.1 | 18.7 | 22.7 | ||||||||
| 5 | 16.2 | 18.8 | 13.2 | 14.3 | ||||||||
| 6 | 23.2 | 23.3 | 15.3 | 20.1 | ||||||||
| Mean number of types consumed | 4.09 (3.93, 4.26) | 4.24 (4.08, 4.40) | 3.41 (3.25, 3.57) | 3.95 (3.68, 4.22) | ||||||||
Notes. RR = rate ratio; CI = confidence interval; NA = not applicable. Rate ratios and P values were adjusted for age and gender.
Yes or no.
Fewer respondents ate some fruit on the day before the survey in other years than in 1995; however the differences were significant only in 2001 (RR = 0.60; 95% CI = 0.41, 0.86; P = .006). Overall, women were more likely than were men to have eaten some fruit on the day before the survey (RR = 1.73; 95% CI = 1.31, 2.29; P < .001), and the likelihood increased with higher education (RR = 1.39; 95% CI = 1.20, 1.61; P < .001; data not shown).
The mean vegetable intake on the day before the survey is also shown in Table 3. Respondents ate 12% fewer cups of vegetables in 2004 than in 1995 (RR = 0.88; 95% CI = 0.82, 0.96; P = .003). Overall, women ate significantly fewer cups of vegetables than did men (RR = 0.92; 95% CI = 0.87, 0.97; P = .004; data not shown). A greater proportion of respondents ate no vegetables on the day before the survey in both 2001 (OR = 0.50; 95% CI = 0.35, 0.70; P < .001) and in 2004 than in 1995 (OR = 0.50; 95% CI = 0.35, 0.72; P < .001). Overall, the likelihood of eating no vegetables on the day before the survey increased with increasing income (OR = 1.16; 95% CI = 1.03, 1.30; P = .013; data not shown).
The variety of vegetables eaten on the day before the survey is also shown in Table 3. The mean number of different types of vegetables respondents reported eating on the day before the survey ranged from 3.4 in 2001 to more than 4.0 in the other survey years. Respondents consumed fewer types of vegetables in 2001 (RR = 0.85; 95% CI = 0.80, 0.90; P < .001) and in 2004 (RR = 0.93; 95% CI = 0.88, 0.98; P < .009) than they did in 1995. Overall, women consumed a greater variety of vegetables than did men (RR = 1.13; 95% CI = 1.09, 1.17; P < .001), and variety increased with higher education (RR = 1.04; 95% CI = 1.02, 1.06; P < .001; data not shown).
Barriers to Increasing Fruit and Vegetable Intake
Table 4 shows that barriers to increasing fruit intake were similar to those for increasing vegetable intake; however, the proportion of respondents reporting them differed. The main reason respondents gave for not eating more of both fruit and vegetables was the perception that they already ate enough (approximately one third and two thirds of participants, respectively). In 2004, respondents were significantly less likely to say they already ate enough vegetables than they were in 1995 (OR = 0.71; 95% CI = 0.55, 0.92; P < .008). Overall, women were less likely than were men to say that they already ate enough vegetables (OR = 0.72; 95% CI = 0.61, 0.86; P < .001), and the belief that “I already ate enough vegetables” increased with age (OR = 1.14; 95% CI = 1.10, 1.19; P < .001) and income (OR = 1.14; 95% CI = 1.04, 1.24; P < .004; data not shown). There were increases in the proportion of the population that perceived lack of variety, poor quality, a lack of time and effort to prepare, and difficulty changing habits as barriers from 1995 to 2004.
TABLE 4.
Main Things That Make It Difficult to Eat More Fruit and Vegetables: Nutrition Monitoring Surveys, Western Australia, 1995–2004
| 1995 (n = 748) | 1998 (n = 751) | 2001 (n = 753) | 2004 (n = 601) | |
| Things that make it difficult to eat more fruit, % | ||||
| Nothing/I already eat enough | 33.4 | 41.3 | 45.2 | 34.5 |
| Not enough variety in store | 7 | 11.9 | 9.3 | 12.2 |
| Cost/Too expensive | 11.8 | 7.7 | 8.1 | 7.9 |
| Don't have enough time | 4.1 | 10.3 | 7.2 | 10.3 |
| Hard to find good quality | 5.5 | 6.1 | 4.6 | 9.1 |
| Don't like | 8.8 | 8.5 | 7 | 7 |
| Difficulty changing habit | 4.2 | 7.5 | 6.7 | 8.7 |
| Doesn't appeal in cold weather | 4.8 | 4.3 | 3.8 | 4.7 |
| Other | 21.5 | 6.1 | 9.4 | 9.5 |
| Don't know | 1.2 | 0.7 | 1.5 | 1.4 |
| Things that make it difficult to eat more vegetables, % | ||||
| Nothing/I already eat enougha | 64 | 66.2 | 67.7 | 59.31 |
| Time taken to prepare | 8 | 13.6 | 10.7 | 14.3 |
| Effort to prepare | 1.9 | 0.32 | 6.4 | 12.5 |
| Don't like | 7.7 | 6.7 | 6.5 | 5.5 |
| Cost/Too expensive | 5.9 | 3.2 | 3.1 | 3.5 |
| Not enough variety in store | 2.1 | 3.7 | 3.4 | 3.7 |
| Hard to find good quality | 1.4 | 2.7 | 1.6 | 4.5 |
| Other | 20 | 3.9 | 7.1 | 8.2 |
| Don't know | 0.5 | 0.9 | 1.9 | 1.7 |
Note. Figures for each year do not add to 100% because multiple responses were allowed.
In 2004, respondents were 29% less likely than in 1995 to say, “I already eat enough vegetables”: odds ratio = 0.71; 95% confidence interval = 0.55, 0.92; P < .008.
DISCUSSION
We demonstrated significant changes in knowledge, beliefs, and some behaviors relating to fruit and vegetable consumption between 1995 and 2004. Most changes occurred after the Go for 2&5 fruit and vegetable campaign that took place in 2002. Approximately twice as many respondents correctly identified the minimum recommended intake for both fruit and vegetables in 2004 as in 1995. These findings are consistent with results from the 2004 monthly campaign tracking survey reported elsewhere.19
The main change in knowledge of the fruit recommendation was a reduction in the proportion reporting a recommended minimum of 3 or more servings per day and a corresponding increase in those reporting 2 servings, in line with the campaign message. This did not appear to have had an immediate adverse impact on consumption, although future trends in knowledge and consumption should be monitored.
The average fruit intake between 2001 and 2004 was stable after the significant decline seen between 1998 and 2001. Although there was a significant increase in the proportion correctly identifying the minimum recommended intake of vegetables, the average number of cups of vegetables reported eaten declined by 12% between 1995 and 2004.
There was also a significant decline after 1995 in the average number of types of vegetables eaten on the day before the survey, by 15% in 2001 and 7% in 2004. Knowledge of the recommended number of servings has been associated with higher intake20; however, the association is not always strong,21,22 suggesting that other factors are important influences on consumption.
Barriers to Increasing Consumption
The main barriers to increasing consumption differed for fruit and vegetables, particularly in the extent of the main barrier, the perception that current intake was adequate. Approximately one third of respondents felt their intake of fruit was adequate, and two thirds felt their intake of vegetables was adequate. These figures were consistent across the surveys, although there was a slight decrease in this perception for both fruit and vegetables in 2004. This confirms the previously identified importance of investigating influences on fruit and vegetable consumption separately.23 Our data support the view that complacency surrounding the need to increase fruit and vegetable intake is related to an optimistic assessment of current intakes.10,24
The actual and perceived adequacy of vegetable intake was similar. Fifty-nine percent of respondents said they already ate enough vegetables in 2004 compared with 35% who actually ate 3 or more cups (6 servings) of vegetables on the day before the survey and a further 24% who reported eating 2 cups (4 servings) of vegetables. Although 59% ate 2 or more pieces of fruit per day, only 35% said they believed that they already ate enough fruit.
Valid and reliable measurement of fruit and vegetable consumption is a challenge for population monitoring surveys.25–27 The measurement method influences the proportion of the population categorized as meeting fruit and vegetable guidelines.26,28,29 A combination of 24-hour food recall and semiquantified food frequency is recommended.28 Although regular nutrition monitoring is paramount, the method is often limited to a few short-answer questions, as in this study, because of respondent burden and funding constraints.
Our survey asked respondents to report intake of cups of vegetables eaten on the day before the survey rather than the usual number of servings a day and, therefore, did not distinguish between the standard serving size of a half-cup of cooked vegetables and 1 cup of salad vegetables. Studies that use self-reporting tend to overestimate fruit and vegetable consumption.7 At more than 35%, the proportion of the population in this study who met the recommended vegetable intake (5 servings or 2½ cups) was inconsistent with the proportion found in other Australian studies in 2004: only 15% in Western Australia19 and 5% in a survey in Victoria.30
Adequate fruit intake was more consistent across different surveys—59% in this study compared with 53% in Western Australia19 and 61% in Victoria.30 Although these methodological differences make comparisons more difficult, it is still clear that as with other Australian and US population-based studies,30–32 a substantial proportion of the Perth population does not meet the recommended intakes of fruit and vegetables.
In addition to the perception that participants' fruit and vegetable intake was adequate, the availability, cost, and quality of fruits and vegetables increased over time as factors influencing intake. The time and effort taken to prepare vegetables was also a major barrier. These factors may become more significant as intention and attempts to change behavior increase. Although consumer perception of the cost of fruit and vegetables as a barrier decreased slightly from 1995, it remained an important issue for fruit intake in 2004. Similarly, the lack of variety and poor quality of fruit increased as an issue over the survey period. Cost as a perceived barrier is complex; Dibsdall et al.24 suggested that consumers budget for the amount of fruit and vegetables they routinely buy but are unwilling to purchase more than this amount and, therefore, see increasing this amount as the expense.
“Time scarcity” has been identified as an independent predictor of fruit and vegetable intake,33 including convenience and time taken in preparation. A “lack of time” was increasingly identified as a barrier to eating more fruit, and the time and effort taken to prepare vegetables increased as a barrier. It is therefore important to consider convenience and the ease of preparation when promoting increases in fruit and vegetable consumption.
We found that women were generally more knowledgeable about the recommended intake of fruit and vegetables than were men. Over the 4 surveys combined, women were 2.5 times more likely than were men to identify the correct number of servings of vegetables and 28% less likely to say they already ate enough vegetables. Women also ate more types of vegetables, had a slightly lower vegetable intake and a higher fruit intake, and were more likely than were men to have attempted to increase their fruit and vegetable intake. In a UK study, Ashfield-Watt et al.34 found that women ate more fruit than did men but fewer vegetables, as did Guenther et al.11 when assessing the intake of the US population. Reasons may be that women eat smaller portion sizes or that as the main food preparers they have a more realistic assessment of their intake than men.
Survey Limitations
The low survey response rate of between 32% and 58% should be considered when one generalizes the findings of this study. The improved participation rate in 2004 may be because of the use of electronic white pages instead of random-digit dialing and more callbacks than in previous years. The improved rate did not appear to change the overall sample characteristics. Higher incomes were reported across the years, probably a result of the use of salary cut-off values reflecting increasing salaries over time rather than changes in sample characteristics. Self-reported surveys are subject to reporting bias; however, the same questions were asked across all 4 surveys so that this bias should not affect the findings.
A limitation of this research is that the surveys were not specifically designed to evaluate the Go for 2&5 campaign. Data relate as much to changes across time as to changes since its implementation in 2002; therefore, it is not possible to say which factors influenced the changes in comparisons of 2004 with 1995; however, the similarity of findings between the 2 surveys before the campaign and the changes reported following it are of interest.
Changes in Knowledge
As reported elsewhere, 90% of the population was aware of the campaign between 2002 and 2004.19 The changes in knowledge of recommended intake that occurred between the 2001 and 2004 surveys suggest that the campaign that was initiated in 2002 had an influence on knowledge about what constitutes a healthful diet. Also, the 2004 shifts in perception of the adequacy of current intake and the effort to prepare vegetables suggest a reassessment of intake in response to the campaign message. The data derived from this series of regular nutrition monitoring are also useful in assisting the further development and implementation of the Go for 2&5 campaign.
The proportion of the population who knew the recommended intake of vegetables remained lower than the proportion who knew the recommended intake of fruit. There were consistent differences each year between the barriers to eating fruit and the barriers to eating vegetables. For these reasons, communicating the ideal number of servings of fruit and vegetables separately and providing practical solutions to addressing the barriers to increasing vegetable consumption in particular are priorities when developing new interventions. Despite improvements in knowledge, the large proportion who consumed less than the recommended intake of fruit and vegetables highlights the need to continue to encourage a healthful diet.
Acknowledgments
The 4 Nutrition Monitoring Surveys were funded by the Department of Health in Western Australia (DOH). Horticulture Australia Limited supported Curtin University of Technology to analyze the data and prepare papers for publication.
The authors acknowledge the staff at the former Nutrition and Research Branches, DOH, who assisted with contracting independent market research companies to administer each survey.
Human Participant Protection
There was no formal approval process from the Department of Health in Western Australia. Accreditation with the Interviewer Quality Control Scheme in Australia was required of market researcher agencies for quality-control purposes. At initial contact, people were told the purpose of the interview and that if they agreed to participate, they could still opt out at any time.
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