The majority of participants with obesity (85%), and overweight (64%) perceived a need to lose weight. Among those in the overweight or obese categories, not perceiving a need to lose weight was associated with being older, male, non-white, not being married or cohabiting, having no formal qualifications (compared to having a degree), having cancer that had spread, and having no comorbidities (compared to 2 or more).
Prevalence of obesity in this sample was 20.7%, lower than the 31.7% previously reported in cancer survivors in the United States [29]. Prevalence of obesity in this sample was also lower than in the general adult population in the United Kingdom, which is estimated to be 28% [30]. In this study, the greatest proportion of participants who thought they should lose weight were in the obese category, followed by the overweight, then healthy weight categories, which is in line with other studies exploring associations between BMI and desire to lose weight [31, 32].
Eighty-five percent of participants in the obese category thought they should be trying to lose weight. This is lower than levels of desire to lose weight among adults with obesity in the general population (94.2%) [33], but considerably higher than levels of accuracy in self-perception of obesity in other studies [19, 34], though it is important to make the distinction between perceiving oneself as having obesity, and perceiving a need to lose weight. For example, participants in this study who thought they should be trying to lose weight may not have perceived themselves as having overweight or obesity. The proportion of participants in the overweight category who thought they should be trying to lose weight (63%) was also lower than the proportion of those with overweight in the general population reporting a desire to lose weight (79.4%) [33]. The overweight category had the lowest proportion of participants whose perceptions of whether they should change their weight were in line with WCRF recommendations of having a BMI within the healthy range, and over 30% participants in this category reported that they did not think they needed to change their weight. A potential explanation for this is that individuals in the overweight category may not have discussed weight with healthcare professionals. Alternatively, they may have been advised not to pursue weight loss by healthcare professionals, friends, and/or family. It is also possible that a subset of participants in overweight and obese categories do perceive themselves as being in these BMI categories, but still do not perceive a need to lose weight due to health or cultural reasons.
Nevertheless, the vast majority of participants with overweight and obesity in this sample did perceive a need to lose weight, suggesting these individuals may be receptive to interventions seeking to support weight management. However, there is currently a lack of programmes designed specifically to support people LWBC. The lack of available support to achieve weight loss may be detrimental to the wellbeing of this group and could contribute to negative feelings and frustration if they are unsuccessful in achieving weight loss despite perceiving a need for it.
Nearly a quarter of healthy weight participants thought they should be trying to lose weight. Though the desire for people LWBC of a healthy weight to lose weight could be seen as concerning, this figure is lower than the reported 35.3% of healthy weight individuals in the general population who want to lose weight [33]. The lower proportion among this patient population may be due to medical advice against unnecessary weight loss, as well as the high average age of participants, as concern about weight is known to decrease with increasing age [35]. However, more research to understand the rationale behind perceiving a need to lose weight in people LWBC of a healthy weight is needed to prevent unnecessary and potentially detrimental weight loss. Furthermore, a future study comparing perceptions of weight, perceived need to change weight, and proportions of individuals who are actively trying to change or maintain their weight, including with analysis across BMI categories, may identify groups who need support actioning this change, as well as those trying to change their weight in a way that may be detrimental to their health.
The regression analysis highlighted demographic and health factors associated with not perceiving a need to lose weight in participants with overweight and obesity. These were older age, being male, non-white, and not married or cohabiting, having no formal qualifications (compared to having a degree), having cancer that had spread, and having no comorbidities (compared to having 2 or more comorbidities). Previous studies have identified associations between older age [25, 36], being male [25], being non-white [25], and having lower levels of education [36] in misperception, particularly underestimation, of weight status, but few studies have investigated perceived need to change weight. These factors may describe a subset of the population who are at risk of health inequalities, which may be prevented through increased awareness of own weight status, and risks associated with overweight and obesity, as well as tailored support in achieving weight loss. Research to understand the reasons for not perceiving a need to lose weight among these groups is needed, as is research on effective targeted support and advice for those with overweight and obesity who underestimate their weight status, and/or who do not perceive a need to lose weight.
The finding that individuals with comorbidities are more likely to perceive a need to lose weight is at odds with previous findings that weight misperception was more common in those with a diagnosed chronic condition [36], though it is again important to make the distinction between weight perception and perceived need to lose weight. Neither the present nor afore mentioned studies collected data on the date of development of comorbid diseases in relation to weight status, therefore interpreting these findings is problematic. With this in mind, some possible explanations for the findings of this study may be carefully considered. It is possible that the care pathways of conditions other than cancer are more successful in raising awareness of weight status in patients and advising them on actions to reduce risks. This is supported by evidence that awareness of having hypertension and dyslipidaemia were negatively associated with weight underestimation [34], suggesting people may be more aware of the associations of overweight and obesity with these conditions than with cancer. The two most commonly reported comorbidities among participants in the present study were arthritis and diabetes, both of which are associated with overweight and obesity [37, 38], therefore healthcare professionals may have advised participants to lose weight to improve their symptoms. However, there is little evidence that diagnosis of comorbid diseases is a successful motivator for weight loss. Future studies using qualitative methods to understand the role of comorbidities in perception of weight status and need to lose weight among people LWBC may improve our understanding of this association.
When considering the clinical and policy implications of these findings we must consider how beneficial it is to increase perceptions of a need to lose weight among individuals LWBC with overweight and obesity. Some studies have found positive associations between weight loss and mortality among breast cancer survivors with overweight and obesity [6, 39], but interpreting these findings is challenging as few studies make the distinction between intentional and disease-related (unintentional) weight loss. A large study using data from three longitudinal cohorts also found that those who perceived themselves as having overweight were at an increased risk of subsequent weight gain, and that this effect was predicted by stress-induced eating [40]. However, those participants were not cancer survivors, who may have different motivations for achieving a healthy BMI. Nevertheless, these studies highlight potential consequences of increasing the proportion of individuals with overweight and obesity who perceive a need for weight loss, especially those who may not need or benefit from weight loss, and in the absence of weight loss interventions tailored for people LWBC. As a recent Cochrane review found that tailored weight loss interventions for people LWBC can lead to significant improvements in anthropometric measures and aspects of quality of life, it seems that there is benefit to participation in such interventions, and further development of weight loss interventions for people LWBC using evidence-based techniques based on behaviour change theory is necessary to appropriately support this group.
This study has a number of strengths and limitations. One strength is the large sample size of 5,835 participants. The study also collected data on perceived need to lose weight, which has been minimally explored to date among people LWBC. Limitations included self-reporting of height and weight data to calculate BMI, which may be associated with under-reporting of weight, particularly in individuals with overweight and obesity [41]. BMI is also an imperfect indicator of nutritional status, especially in individuals LWBC for whom cancer cachexia is a concern [42]. Non-white ethnicities were also underrepresented in the sample. Additionally, participants who ignored or skipped the question on comorbidities were coded as having 0 comorbidities, which may be inaccurate.
In conclusion, individuals LWBC with obesity are the most likely to perceive a need to lose weight, followed by those in the overweight, then healthy weight BMI categories. Not perceiving a need to change weight in those with overweight is common, and more research is needed to understand the rationale for this in this population. Among those with overweight and obesity, factors associated with not perceiving a need to lose weight included demographic and health variables, which may indicate a subset of people LWBC who need additional advice and support with weight management. Development and increased availability of weight management programmes for people LWBC is needed.