Obesity remains a pressing global health issue, contributing significantly to the burden of chronic diseases, including cancer, type 2 diabetes, and heart disease. The condition is also a leading factor in premature mortality. More recently, evidence has linked obesity to worse outcomes in COVID-19, further emphasising its impact on public health. These risks have driven governments and health agencies worldwide to prioritise the development of effective strategies to help people lose weight and maintain a healthier lifestyle.

Primary care is uniquely positioned to address this challenge. As the first point of contact for many individuals within the healthcare system, primary care offers a platform for delivering weight management services. Patients typically consult their primary care doctor an average of four times per year, providing ample opportunities to implement interventions aimed at weight loss. International guidelines recommend that healthcare professionals opportunistically screen patients and encourage weight management, making primary care a critical setting for these efforts.

Systematic Review of Weight Management Interventions

A systematic review conducted by LeBlanc et al demonstrated the effectiveness of behavioural interventions in promoting weight loss. These interventions, which included components such as goal setting, dietary guidance, and behavioural support, achieved an average weight loss of 2.4 kilograms over a period of 12 to 18 months. While these findings are promising, many of the interventions reviewed were conducted in non-primary care settings, such as universities or research centres, raising questions about their applicability to routine clinical practice.

Recognising this gap, an updated review was undertaken to focus specifically on weight management interventions delivered within primary care settings. The updated analysis incorporated data from new trials published since the original review, providing a more comprehensive understanding of the effectiveness of these interventions. The review evaluated changes in body composition, including weight and waist circumference, and identified characteristics of successful programs that could inform health policy and service design.

Weight Loss and Intervention Characteristics

The updated review confirmed that weight management interventions delivered in primary care are effective, resulting in a mean weight loss of 2.3 kilograms over 12 months. Reductions in waist circumference were also observed, with an average decrease of 2.5 centimetres. Although these changes may seem modest, they are clinically significant. Even a small weight loss of 2–5% has been shown to improve key health markers, including systolic blood pressure, glucose levels, and triglycerides, highlighting the importance of these interventions in reducing obesity-related risks.

The frequency of contact between patients and healthcare professionals emerged as a critical factor influencing the success of these interventions. Programs involving at least 12 sessions, delivered face-to-face, via telephone, or through a combination of both, achieved greater weight loss. This finding highlights the need for consistent and sustained engagement with patients as a foundation of effective weight management strategies.

Role of Healthcare Professionals in Intervention Delivery

The review also examined the type of practitioner delivering the interventions and found that non-medical professionals, such as health coaches or trained lay workers, were as effective as general practitioners (GPs) in facilitating weight loss. One possible explanation for this finding is the higher frequency of interactions with non-medical practitioners, which may enhance patient adherence and motivation. Furthermore, interventions involving GP endorsement or supervision appeared to boost the perceived importance and credibility of the program.

From a cost perspective, non-medical practitioners offer a more economical alternative to GP or nurse led interventions. This makes them a practical option for resource-limited healthcare systems. However, the involvement of GPs in a supportive or supervisory capacity remains important, as it ensures that the interventions are integrated within the broader context of patient care.

Limitations and Challenges in Implementation

Despite the encouraging results, the review identified several limitations. The interventions included in the analysis varied widely in their design and implementation, resulting in significant heterogeneity in the meta-analyses. While subgroup analyses accounted for some of this variation, additional factors influencing outcomes remain unexplained. Furthermore, the majority of trials were conducted in economically developed countries, limiting the generalisability of the findings to lower income settings.

Another challenge was the difficulty in distinguishing the specific components of interventions and identifying who delivered them. High attrition rates in some trials further complicated the interpretation of results, as participants who dropped out were more likely to have less favourable outcomes. These limitations highlight the need for future research to address gaps in understanding and improve the design of weight management programs.

Comparison with Previous Research

The findings of the updated review are consistent with earlier studies, such as the trial by Ahern et al, which reported a weight loss of 2.7 kilograms and a waist circumference reduction of 4.1 centimetres following a referral to a commercial weight management program. However, the current review’s focus on primary care settings provides unique insights into the feasibility and effectiveness of these interventions within routine clinical practice.

The relatively modest reductions observed in primary care interventions compared to more intensive programs conducted in research or university settings reflect the practical constraints of delivering care in a primary care environment. These findings emphasise the need for realistic expectations when designing and implementing weight management services in real-world healthcare settings.

Policy Implications and Recommendations

The review’s findings have important implications for health policy. Integrating weight management interventions into primary care services could help address the global burden of obesity by leveraging the accessibility and reach of primary care. Programs should include at least 12 sessions, combining face-to-face and remote interactions, to maximise their effectiveness. Training healthcare professionals to address weight management confidently and effectively is essential, as many practitioners report discomfort with raising the issue and scepticism about the success of interventions.

Non-medical practitioners should play a central role in delivering these interventions, supported by GP endorsement and supervision. This approach balances cost-effectiveness with the need for professional oversight, ensuring that patients receive high-quality care. Policymakers must also consider the resource availability within primary care settings to ensure that interventions can be implemented sustainably.

Future Research Directions

While the review highlights the effectiveness of primary care interventions, several questions remain unanswered. Future research should explore the specific components of interventions that are most strongly associated with weight loss. Additionally, studies should examine the equity of these programs to ensure that they are accessible and effective for diverse populations, including those in low-income settings or those affected by weight-altering medications.

An individual patient meta-analysis could provide deeper insights into the factors driving variations in outcomes, enabling the development of more personalised and effective interventions. Addressing these gaps will be critical to refining weight management strategies and ensuring their long-term success.

Conclusion

Weight management interventions delivered in primary care are effective and feasible, offering a practical solution to the global obesity epidemic. Although modest, the observed reductions in weight and waist circumference translate into significant health benefits, reducing the risk of chronic diseases and improving overall population health. Integrating these interventions into primary care services, supported by adequate resources and training, can help mitigate the growing burden of obesity and its associated health risks. Policymakers and healthcare providers should prioritise these programs as a vital component of comprehensive obesity management strategies.

References

Madigan, C. D., Graham, H. E., Sturgiss, E., Kettle, V. E., Gokal, K., Biddle, G., Taylor, G. M. J., & Daley, A. J. (2022). Effectiveness of weight management interventions for adults delivered in primary care: systematic review and meta-analysis of randomised controlled trials. BMJ (Clinical Research Ed.), 377, e069719. https://doi.org/10.1136/bmj-2021-069719

LeBlanc ES, Patnode CD, Webber EM, Redmond N, Rushkin M, O’Connor EA. Behavioral and Pharmacotherapy Weight Loss Interventions to Prevent Obesity-Related Morbidity and Mortality in Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA 2018;320:1172-91. doi:10.1001/jama.2018.7777 

Ahern AL, Wheeler GM, Aveyard P, et al. Extended and standard duration weight-loss programme referrals for adults in primary care (WRAP): a randomised controlled trial. Lancet 2017;389:2214-25. 10.1016/S0140-6736(17)30647-5.