The principal findings from this study are that FV intake of the US adult population is inadequate according to recommendations from the federal government and significantly lower among overweight and obese compared to the normal-weight individuals. Although the FV-BMI status association was attenuated after controlling for the PSD variables, the adjusted association remained significant. Therefore, the significant inverse association between BMI status and FV intake is not necessarily a spurious finding due to potential confounding factors that are significantly associated with both BMI status and FV intake. Only a quarter of the population meets the 2005 Dietary Guidelines recommended minimum intake of 5 FV servings per day. Furthermore, less than 4% of respondents consumed at least 9 servings of FV per day, the recommendation for an energy intake of 2,000 kcal/day.
These findings regarding low FV intake in overweight and obese adults may have important public health implications. Population weight management could conceivably be enhanced by increased intake of FV [22
]. Low FV intake level was significantly associated with each of the demographic, SES and lifestyle variables. Notably, FV intake was lower in individuals who were male, lower in SES indices, current smokers, and physically inactive. Reduced FV intake in the low income group may reflect the higher cost of nutrient-dense foods including fruits and vegetables [23
]. Nevertheless, the employed participants consumed less FV than other groups. Although, the underlying reasons for this finding are unknown, provision of FV as snacks at workplaces might increase FV intake for the employed groups. The FV intake of former smokers is comparable to that of the general population (table ). It is unknown however whether smoking cessation might have induced higher FV intake (compared to the current smokers) to reduce potential weight gains [24
]. After all, as shown in the results section, the low FV intake in the obese group is even poorer when combined with lower indices of SES, smoking status, and physical inactivity (table ).
Taken together, our findings suggest that various public health strategies to reduce obesity by recommending increased physical activity and a healthy diet might have not been sufficiently effective to meet goals, despite the pro minent 5-A-Day national campaign initiated in 1991 [25
]. Whether this reflects a limitation in the design of such programs, their implementation, their efficacy in promoting FV consumption, or the efficacy of FV consumption in reducing obesity is unclear. One plausible factor might be insufficient effort in building (or eliminating) environments that can promote (or diminish) both physical activity and FV intake at the personal and public levels [26
]. Given the significant medical complications of obesity, more effective environmental modifications to promote easier access to places for physical activities, increase in local FV markets, and enhanced neighborhood safety are being broadly considered [29
] and in parallel with government policy and programs [30
]. The 2008 Farm Bill provisions, in particular, have increased the availability of FV in USDA initiatives such as school food service, Women's Infants and Children's (WIC) program, and Food Stamp Program, the latter of which has been renamed as Secured Supplemental Nutrition Assistance Program (SSNAP) providing financial incentives toward promotion of FV purchases.
Taxation on high calorie-dense foods and beverages in conjunction with efforts to increase the difficulty in their access is also being considered by some as a part of policy and environmental modifications [31
]. Broader health insurance coverage, which remains as a significant moderator in the multivariate backward elimination, could also be conjectured to be helpful since increased utilization of health care services might increase awareness of the benefits of a healthy diet, physical activity, and weight loss. When implemented, these policies and programs might effectively enhance physical activity and FV intake and reduce obesity prevalence with greater sustainability, compared to information dissemination alone. In addition, sustained implementation of innovative interventions could also plausibly aid in reducing the population BMI through an increase in FV intake [32
]. For example, family-based studies have suggested that interventions targeting increased FV intake may be as effective those targeting reduced high-fat/high-sugar foods for childhood obesity prevention [33
The interpretation and implication of the present study findings should be made in the context of several limitations. First, all data were obtained by self-report, which is subject to bias and potential underestimation of BMI [31
]. The BRFSS-07 underestimated BMI [35
], though not sizeable, when compared to NHANES 1999–2004 measured prevalence [36
]. Nevertheless, the FV consumption items were previously reported to have moderate reliability and validity [37
]. Furthermore, a recent study showed that self-report BRFSS responses are highly correlated with objectively measured constructs such as human well-being [38
]. Second, actual FV serving portion size consumed by respondents is unknown. The questions in the BRFSS-07 were based on an implicit assumption of one serving being equivalent to a half cup, which can affect the validity of the reported FV servings, although the FV intake items were previously reported to have moderate reliability and validity [37
]. Another limitation concerns missing data. Subjects without complete information about the PSD variables subjects (N = 327,931) consisted of 24% of the respondents. However, the prevalence of FV5+ among these subjects was not substantively affected, with an estimate of 24.8%. Likewise, the prevalence across BMI status groups remained little affected with estimates of 27.9%, 23.9% and 22.0% in the normal-weight, overweight and obese groups, respectively. Furthermore, the multivariate analyses were based on the subjects with complete information. Finally, persons without telephone service, those in institutions or those in the military, were not included in the BRFSS.
In conclusion, US adults in general consumed much fewer servings of FV than recommended by the USDA 2005 guidelines: 24.6% of adults consumed FV 5 times or more per day, and less than 4% consumed 9 servings/day or more. Obesity, SES, and physical activity are associated with poor FV intake, a fact which may merit consideration when developing policies and interventions to increase FV intake. Finally, future studies should examine whether the FV-BMI status associations are also applicable to the general pediatric and adolescent populations.