Increasing Motivation for Lifestyle Change Is Not Enough to Treat Obesity

Treat Obesity According to the World Health Organization, obesity affected 600 million people worldwide as of 2016 and increases risk for morbidity andmortality. Comprehensive lifestyle interventions, alone or in combination with pharmacologic treatment or bariatric surgery, are considered key for weight loss (1). Given the large amount of effort and motivation needed to restrict caloric intake and increase physical activity, motivational interviewing (MI) is a popular component of many lifestyle interventions. Motivational interviewing is an evidence-based, collaborative communication style that aims to strengthen a person's motivation for and commitment to change (2). Although MI is most commonly used for addictions (alcohol and smoking cessation) or for promotion of specific healthy behaviors, prior systematic reviews of MI for weight loss have shown mixed results, with many studies incorporating MI as part of a behavioral weight management program (BWMP) (3). However, it is unclear whether MI by itself is effective for weight loss, independent of other intervention components. In their article, Michalopoulou and colleagues systematically reviewed and synthesized evidence from 11077 participants in 46 randomized controlled trials of BWMPs (4). Participants in BWMPs using MI lost more weight at 6 months than participants receiving no or minimal interventions ( 0.88 kg [95% CI, 1.27 to 0.48 kg]; I= 0%). However, there was no difference between BWMPs with MI compared with lower-intensity ( 0.88 kg [CI, 2.39 to 0.62 kg]; I= 55.8%) or similar-intensity ( 1.36 kg [CI, 2.80 to 0.07 kg]; I= 18.8%) interventions without MI. These results were similar at longer-term followup. Thus, it appears that MI's unique contributions to weight loss outcomes were negligible. Analyses were limited by sparsity of data and high heterogeneity of studies with regard to intervention type, content, and duration. Strengthening motivation through MI is insufficient for weight management because obesity is a disease with a complex etiology, including multilevel factors that are outside the patient's control. These include but are not limited to genetics, inflammation, medications, composition of the microbiome, psychological stress, chronic pain, access to recreational facilities, access to healthy food, and environmental toxins, which interact to cause obesity and make weight loss difficult (5). Losing weight involves changing several behaviors, especially the quality and quantity of food consumed. It is particularly challenging for most of us to avoid exposure to unhealthy foods, and the mere sight or smell of unhealthy foods can trigger cravings and overeating (5). It is especially difficult for those living in food deserts or with food insecurity to find healthy options. The human body is resistant to weight loss through caloric restriction, which alters hormonal signaling for hunger and satiety and reduces metabolic rates. Because of these biological changes, even with continued caloric restriction, weight loss typically reaches a plateau by 6months, and weight regain inevitably occurs if lifestyle behaviors return to baseline (5). For these reasons, even in an intensive program with high retention rates (unlike real-life practice, with poor uptake and high dropout rates), only half of participants have clinically significant (≥5%) weight loss (6). Although not effective as a standalone weight loss intervention, MI may still have an important role in weight management. It improves specific health-promoting behaviors such as physical activity, which is important for weight maintenance (1). Training clinicians to use the principles of MI (for example, expressing empathy and respecting autonomy) provides a framework to engage patients in healthy behaviors, and we have had success teaching physicians to use it as part of the 5As model of obesity counseling (Assess, Advise, Agree, Assist, Arrange) (7), which is covered by Medicare. Furthermore, Michalopoulou and colleagues found that 7 of 10 studies reported that MI increased weightmanagement engagement, andMI has been shown to improve medication adherence in other contexts (3). With the recent advent of highly effective anti-obesitymedications—such as semaglutide (a glucagon-like peptide-1 agonist), which leads to a mean weight loss of about 15% (8) but also requires uncomfortable injections and causes gastrointestinal adverse effects that could deter use—future studies should test MI as an approach to increasing adherence to this and other effective obesity treatment options. Although we believe that MI remains an important tool for treating obesity, we caution providers who use MI or other counseling techniques to avoid exacerbating obesity stigma. Many patients with obesity report feeling discriminated against and blamed for their disease in health care settings (9). Even after achieving the positive health benefits of improved diet, sleep, and physical activity, patients and their providers may interpret failure to lose weight as a personal shortcoming (9), even though lifestyle intervention alone often does not produce long-term weight loss. Obesity stigma can dampen patients' self-efficacy beliefs, discourage future weight loss attempts, and lead to maladaptive eating behaviors. Further, having MI interventionists focus on “controllable” factors to achieve weight loss through lifestyle changemay unintentionally lead to stigma. For instance, medical students who attributed obesity to controllable behavioral factors demonstrated poorer counseling skills and reported more obesity bias (10). Thus, health care providers and other MI interventionists should receive adequate training about the causes of obesity, the expected outcomes of various obesity treatments, and obesity stigma to avoid blaming the patient for this multifactorial disease and should manage their expectations for what is achievable with any given obesity treatment.