New research shows that weight stigma—not body weight itself—has the biggest impact on mental health and healthy behaviours in the years following weight-loss surgery.
The study found that patients who had undergone metabolic bariatric surgery, commonly referred to as weight-loss surgery, tended to experience a significant reduction in weight stigma. This decrease—not a lower BMI (body mass index)—was linked to improved mental health and healthier eating habits. By contrast, those who continued to experience stigma after surgery were more likely to report higher levels of depression, anxiety, and disordered eating.
Researchers surveyed nearly 150 people who had received the surgery, which remains the most effective evidence-based treatment for severe obesity. The procedure is known to reduce many health risks more common in people with obesity, including type 2 diabetes, heart disease, and all-cause mortality.
“We think of a lot of health issues for these patients as being a given,” said Dr Larissa McGarrity, the study’s lead author and a clinical psychologist in physical medicine and rehabilitation at University of Utah Health. “But the cumulative effect of stigma and discrimination actually contributes to a large part of the physical and mental health problems that we disproportionately see for patients with obesity compared to the general population.”
The results are published in Health Psychology.
While many assume weight-loss surgery leads to a guaranteed improvement in quality of life, McGarrity noted that this is not always the case. Some areas, such as social support and satisfaction in romantic relationships, may actually worsen.
However, participants in the study did report much lower levels of weight stigma—shame, blame, and guilt around body weight or shape—in the years following surgery.
McGarrity, who is also an associate professor at the Spencer Fox Eccles School of Medicine at the University of Utah, said the degree of change in experienced weight stigma was especially notable. “The degree of change far exceeded clinically established norms in terms of what’s meaningful for a patient’s life and the impact they would notice,” she said.
This reduction in stigma was associated with significant improvements in both mental and physical health. Previous research has shown that the chronic stress of weight stigma contributes directly to many of the health risks associated with obesity. In this study, patients who experienced less stigma after surgery reported lower levels of anxiety and depression. They were also less likely to engage in disordered eating, such as binge eating, and more likely to maintain their weight loss over time.
Importantly, McGarrity noted that weight loss itself was not responsible for these improvements. Changes in BMI did not correlate with depression, anxiety, or dysregulated eating—suggesting that social factors, rather than biological ones, are driving the changes in health and wellbeing.
Not all patients experienced a drop in stigma. For around 40 per cent of respondents, weight stigma persisted, continuing to affect their quality of life and increasing their risk of mental health issues, disordered eating, and weight regain.
As the survey was conducted among patients treated at University of Utah Health, the researchers acknowledged that further studies will be needed to determine whether the findings apply to more diverse populations.
The authors say their work highlights the urgent need to address weight stigma in both healthcare settings and society more broadly.
“The wide-ranging effects of weight stigma are one of the most important things I’m thinking about from both a research and clinical perspective,” McGarrity said. “Weight loss is helpful for a whole lot of things, but that change in weight stigma may actually be the more powerful thing for mental health and quality of life over time.”