Healthcare without Harm: Unpacking Weight Science

Healthcare without Harm: Unpacking Weight Science Backgrounder

Long-standing narratives about weight and health have become ingrained in healthcare and reinforce weight stigma. An understanding of weight science is crucial to reduce weight stigma and provide equitable patient care.

Health is largely determined by the social determinants of health rather than individual health behaviours or weight. 

The dominant narrative in our society is that health is a matter of individual choice and behaviour change. This narrative fails to recognize the impact of the determinants of health and the complex systemic factors that influence health and wellbeing, most of which are outside of a person’s individual control (1).

“Weight is not a behaviour and should not be a target for behaviour change” (2). Interventions should promote health as the primary motivator for behavior change, rather than reinforcing weight-centric messages that perpetuate stereotypes and shame individuals in larger bodies (3). 

The emphasis on personal responsibility for weight fails to acknowledge the systemic barriers which impede optimal health. The context of a patient’s life should be acknowledged and considered when providing health behaviour recommendations. 

The relationship between weight and health is often overemphasized. 

While a small to moderate increased risk of some health outcomes has been associated with larger body size, there may be factors mediating this relationship (5). These include the confounding impact of weight stigma, weight cycling, the social determinants of health and health behaviours (4-7). Weight stigma alone has been found to have negative impacts on health and wellbeing (5,6,8).

The emphasis on achieving “optimal” weight implies that there is a universal standard for body size, despite evidence that individuals in larger bodies can be metabolically healthy, while those in smaller bodies can still face metabolic and cardiovascular risks (9-11).  Regardless of any health impacts attributed to body size, it’s important to treat the patient with respect in the body they have.

Weight loss diets don’t work. 

Western culture oversimplifies body weight as a matter of choice, perpetuating the belief that individuals in larger bodies could easily reduce their weight by diet and physical activity. In reality, body weight is determined by a complex interplay of factors including genetics, environment and determinants of health (12). While individuals may be able to achieve short term weight loss, a significant body of research has demonstrated that dieting behaviours do not typically lead to substantial and sustained weight loss (13-15). Biological mechanisms designed to protect against starvation make sustained weight loss difficult by favouring weight regain (12, 17). The lack of long-term data on weight maintenance challenges the idea that weight loss is beneficial to health in the long-term (15). 

While pharmaceutical and surgical interventions have demonstrated greater success with short-term weight loss than  lifestyle changes, there is also variation in outcomes, lack of long-term data, and significant risk involved. Despite the widespread belief that weight loss is necessary to improve health in larger bodied patients, health can be improved without weight loss through changes in health behaviours. (6, 15, 17). 

Dieting (food restriction) causes harm, especially for youth. 

Comments about weight, body shape, or eating habits to children and youth can trigger lifelong challenges with food, body image and self-esteem. Dieting behaviours are alarmingly common.  Nearly half  (49.1%) of Ontario students in grades 7-12  report that they skipped meals  or altered their eating patterns in the past month to try and change their weight, shape, or muscles (18). 

While encouraging weight loss has often been seen as a low risk intervention, it can cause significant short-term and long-term harm to mental and physical health. Attempts to lose weight may begin with rigid and restrictive rules which can impact a person’s relationship with food, movement, and their body. Dieting has been identified as a significant risk factor in the development of disordered eating and eating disorders (19,20). For growing children and youth, these risks are even more severe.  Energy restriction during key developmental stages can impair growth, delay puberty, and interfere with bone development. Disordered eating and dieting in children and youth is associated with increased risk of depression, anxiety and long-term metabolic complications.  Additionally, weight cycling (repeated weight loss followed by weight regain) has shown to have independent negative effects on health, regardless of body size (7, 21). 

Consideration should be given to adults who have struggled with dieting in their youth, chronic dieting, disordered eating and eating disorders. Experiences of weight stigma and internalized weight bias can negatively affect health (2). Patients in larger bodies, like those of any body size, can be at risk for malnutrition when intake is restricted (22,23). 

Patients should be fully informed of the potential risks associated with pharmaceutical and surgical weight loss interventions.

Understanding the risks and limitations of weight loss interventions is essential for informed decision making. Research and promotion on these treatments is often funded by pharmaceutical companies, which leads to potential biases. Prior to initiating any intervention, patients should be made aware of the possible impacts on their quality of life – both positive and negative. 

Bariatric surgery has been associated with several risks, including dumping syndrome (24, 25); malnutrition and nutritional deficiencies (24, 26, 27); disordered eating and eating disorders (24,28,29); increased substance use (30, 31); and elevated suicide risk (24, 32-34). Weight recurrence after bariatric surgery is also common (24, 35).

Pharmaceutical interventions commonly cause gastrointestinal side effects (36-39), may impair patients ability to consume adequate macro and micronutrients (40, 41) and can lead to serious complications such as acute gallbladder disease or pancreatitis (39). Weight recurrence is common, particularly if medications are discontinued (42-44). 

While some patients may feel the potential health benefits of these interventions are worth the risks, this is not universally true. For some individuals, similar health benefits may be achieved through weight-inclusive approaches that carry fewer risks. A patient’s autonomy to decide on treatment options after being fully informed should always be respected. 

Body Mass Index (BMI) is not a reliable tool to assess an individual’s health. 

Despite its widespread use, BMI is a flawed measure of an individual’s overall health status or risk. The use of BMI to assess health can perpetuate harm by making broad assumptions about health based on weight and restricting access to health services. There are many other factors that better predict health, including health behaviours, biochemical markers of disease,  and the determinants of health.

BMI was designed in the 19th century to study population averages, not individual health, and initially studied using white European male subjects. BMI categories have been influenced by commercial and pharmaceutical interests. BMI does not consider individual factors like muscle mass, bone density, or fat distribution. 

Although epidemiological studies show some correlation between BMI and various health conditions, the association is typically weak to moderate (4). All-cause mortality is lowest in BMI categories considered “overweight” and “obesity class 1” compared to the BMI considered to be “normal” (45,46). Weight-centric biases from researchers, funders, media, and institutions often lead healthcare providers to overestimate the risks for individuals in larger bodies and underestimate those for individuals in smaller bodies (5). This misalignment can adversely affect the preventive care and treatment that both groups receive. 

In short, BMI fails to consider a nuanced picture of what impacts human health and overemphasizes the role of body weight in determining overall health. 

Weight-inclusive care can improve health outcomes for all patients. 

A weight-inclusive approach recognizes that body size diversity is a natural part of being human. It rejects the idealization and pathologization of specific weights and acknowledges that BMI and weight are not measures of health. Overall, a weight-inclusive approach in healthcare aims to consider how all aspects of a patient’s life impact their health and provides compassionate, non-judgmental and equitable care for all humans.

Research has suggested that a weight-inclusive approach that focuses on behaviors rather than weight leads to improvements in physiological measures, health behaviors, and psychosocial outcomes (15). A weight-inclusive approach has been shown to be comparable to a weight-centric approach when assessing cardiovascular biomarkers (15). A weight-inclusive approach may be more attainable with fewer risks, allowing patients to make more sustained changes that impact their health rather than getting discouraged by attempts at weight loss. 

ODPH would like to thank academic and clinical colleagues for their helpful input.

References:

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