To our knowledge, this is the first study to compare adult ambulatory outpatients’ self-reported heights, weights, and BMIs, desired weights and BMIs, and self-perceived BMI categories with their actual heights, weights, and BMIs and determine factors associated with patient accuracy of self-perceived BMI categorization and rates of clinicians’ documented diagnoses of obesity. The key findings were that 1) 70% of the patients had overweight or obesity; 2) the overall average self-reported height and weight were significantly taller and lighter than the average actual height and weight, resulting in an average self-reported BMI that was significantly less than the average actual BMI; 3) the average desired weight loss was substantial and, if achieved, would result in a normal average BMI; 4) many overweight and obese patients inaccurately perceived their BMI category, and accuracy decreased significantly with higher actual BMI category; 5) desired weight loss increased significantly with higher self-perceived and actual BMI categories; 6) female sex, higher education level, smoking status, and lower actual BMI were associated with increased accuracy of self-perceived BMI categorization; and 7) only one-quarter of obese patients had obesity as a diagnosis documented by their clinicians in their medical records.
The finding that 70% of the patients in our study had overweight or obesity reflects the epidemic of unhealthy weight in the United States [10],[31]. A number of studies have assessed patient self-reported height [6]-[9],[15]-[17],[20],[21],[23]-[27],[35],[36] self-reported weight [6]-[9],[15]-[17],[20],[21],[23]-[27],[35],[36] and self-reported BMI (calculated on the basis of self-reported height and weight) [6]-[9],[15]-[17],[20],[21],[23]-[27],[35],[36]. However, only 4 studies have compared self-reported height, weight, and BMI with actual height, weight, and BMI [7],[16],[25],[36]. Consistent with the results of prior studies [24]-[26],[35], the patients in our study reported being taller and lighter than they actually were. Although self-reported heights and weights may be useful for epidemiologic studies, our results suggest that clinicians should not rely on these self-reported data for clinical decision making. Instead, actual measurements of heights and weights should be used. Notably, the US Preventive Services Task Force (USPSTF) recommends screening all adults for obesity by calculating BMI from measured weight and height [37]. (The USPSTF uses the same BMI categories as NIH, as described in the Methods and Procedures section [34]).
More concerning is the finding that many overweight and obese participants in our study inaccurately self-perceived their BMI categories; nearly all inaccurate participants perceived they were in a lower BMI category than they actually were. Furthermore, the higher the actual BMI category, the more inaccurate was the self-perceived BMI category, suggestive of a dose–response relationship. Higher education, smoking status, and female sex were associated with greater accuracy of self-perceived BMI category. According to the Health Belief Model, an overweight or obese person must recognize his or her unhealthy weight and its associated health risks before he or she will modify unhealthy lifestyle behaviors such as lack of exercise and poor diet (eg, processed foods, fats, decreased fruits and vegetables) and lose weight [28].
Nonetheless, most of the participants in our study desired to lose weight, and the average desired weight loss was substantial (9.4 kg). If the participants achieved this weight loss, the overall average BMI would be normal (24.8 kg/m2). This novel finding suggests that, despite inaccurate self-reporting of heights and weights and self-perceived BMI categories, patients recognize the need for healthy weight. Unsurprisingly, desired weight loss was associated with self-perceived BMI category. For example, patients who perceived they were overweight or obese desired more weight loss than patients who actually were overweight or obese. Health care professionals can leverage these findings in order to discern patients’ self-perceived weights, correct misperceptions, and make recommendations regarding management and achieving healthy weight. Overweight and obese patients who are counseled about their unhealthy weight by their health professionals may have more accurate self-perceptions of weight and may be more likely to attempt to lose weight [7],[29],[30]. Furthermore, evidence suggests that behavioral interventions, with or without pharmacologic interventions, result in substantial weight loss [37],[38]. Although such interventions may not result in a given patient’s desired weight loss, it is important to recognize that modest weight loss (5% to 10%) can mitigate cardiovascular risk factors [39]. However, for these interventions to be effective, clinician diagnosis and patient self-perception of unhealthy weight and its health risks are essential.
Although health care professionals are uniquely positioned to help overweight and obese patients recognize their unhealthy weight, these professionals, like those in our study, often fail to do so. Only one-quarter of the participants in our study who actually were obese had obesity documented as a diagnosis in their medical records by their clinicians. This phenomenon of obesity “hiding in plain sight of the physician” has been observed previously at our institution [29] and elsewhere [31]-[33]. If overweight and obese patients do not perceive their weight as unhealthy and overweight and obesity hide in plain sight, then it is unlikely unhealthy weight will be addressed by health care professionals before weight-related health events (eg, diabetes, myocardial infarction, sleep apnea, osteoarthritis) occur.
Why do health care professionals fail to recognize and diagnose overweight and obesity? As mentioned, some clinicians do not regard obesity as a disease [5]. Yet, now the AMA does [4]. Furthermore, until recently, Medicare did not reimburse for obesity counseling. Thus, there was no financial incentive for diagnosing obesity. Now, such an incentive exists [40]. Some clinicians may regard counseling overweight and obese patients to engage in healthy behaviors and lose weight as futile. However, evidence suggests that behavioral interventions (with or without pharmacologic interventions) are effective [37]. Barriers cited by health care professionals at our institution include lack of time to discuss patients’ weights, other clinical priorities, perceived lack of effective treatments, provider unpreparedness to discuss obesity, patient sensitivity to the term “obesity”, and other factors (Cook KE, Salerno MS, Williams BJ, Klauer KM, Hensrud DD, Collazo-Clavell ML, Hurt RT, Wermers RA, Kebede EB, Mueller PS, unpublished data). Other barriers include lack of infrastructure to meet overweight and obese patients’ needs, patients’ concerns about stigma, and “antifat bias” by clinicians [33].
Health care institutions should implement measures that address these barriers (eg, electronic medical record prompts that trigger clinicians to inform overweight and obese patients of their unhealthy weights and the associated risks and discuss treatment options with affected patients). Clinicians uncomfortable with counseling affected patients about overweight and obesity should be offered communication training. Institutions should also provide resources that assist clinicians in providing the multimodal, high-intensity counseling and follow-up that are needed to help patients lose weight.
This study has a number of limitations. First, the average age of the participants was 63 years, more than a third lived in Minnesota, and most had at least a high school education. Second, we were unable to determine patient ethnic and socioeconomic status; these factors have been associated with varied self-perception of weight and self-recognition of obesity [6],[9],[16],[21]-[23]. Hence, the same study conducted with a patient population with different characteristics might yield different results. Future studies should include populations with broader demographics to allow for analysis between ethnic groups, levels of education and socioeconomic status, and other patient characteristics. Third, some people with BMIs higher than 25 kg/m2 have low body fat. Also, body fat distribution affects risk for comorbid disease. In overweight and obese patients, higher waist circumference, an indicator for central obesity, is associated with higher risk [34]. Our study would have been strengthened by including waist circumference, skinfold measurement, and body fat composition analysis as variables.