Worldwide, there are approximately 890 million people living with obesity, and in Portugal, 15.9% of the population is obese, while 37.3% are overweight.

Obesity and Metabolic Surgery, also known as Bariatric Surgery, is a highly effective therapeutic option for the treatment of obesity and numerous associated conditions such as type 2 diabetes, hypertension, sleep apnoea and others.

It is indicated for patients with a body mass index (BMI) ≥35 kg/m², or ≥30 kg/m² and when obesity-related diseases or functional limitations are present.

A comprehensive and multidisciplinary assessment throughout the entire process is essential, ensuring continuous support and optimising both the effectiveness of the surgical procedures and the patient’s adaptation to a new lifestyle.

Obesity surgery is recognised and recommended by organisations such as the World Health Organization and the International Diabetes Federation. This approach goes far beyond simple weight loss: it acts directly on the hormonal and metabolic mechanisms that regulate blood glucose and appetite, promoting rapid and sustained improvements.

Among the most commonly performed techniques are the Gastric Bypass and the Sleeve Gastrectomy, procedures supported by robust evidence demonstrating significant weight loss and remission of type 2 diabetes, frequently allowing a substantial reduction or even discontinuation of antidiabetic medication, as well as a reduction in cardiovascular risk, improved quality of life and increased life expectancy.

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In recent years, GLP-1 receptor agonists, the well-known injectable therapies, such as semaglutide (Ozempic®) and tirzepatide (Mounjaro®) have gained prominence in the treatment of obesity and diabetes, promoting weight loss (considerably lower than that achieved with surgery) and improved metabolic control. However, these medications require continuous administration to maintain results, and weight regain frequently occurs after discontinuation. In addition, the long-term cost and the need for ongoing adherence may represent important limitations, with treatment discontinuation rates reported at 72%.

Obesity surgery, in turn, triggers profound hormonal changes, including increased endogenous GLP-1, reduced ghrelin and increased leptin levels, which decrease appetite, enhance satiety, improve insulin sensitivity and reduce systemic inflammation, functioning as a structural rather than purely pharmacological intervention.

Unlike isolated pharmacological therapy, its effects tend to be more durable, with proven long-term impact. Average weight loss at two years following obesity surgery is 28.3%, compared to 10.3% with pharmacological therapy, and studies have demonstrated weight loss of 34.4% at ten years.

Nevertheless, it is important to emphasise that both surgery and treatment with GLP-1 receptor agonists necessarily require consistent lifestyle changes: a balanced diet, regular physical activity and multidisciplinary clinical follow-up are indispensable pillars for long-term success.

In summary, obesity surgery stands out as the most effective strategy with the greatest potential in the treatment of obesity, sustained remission of type 2 diabetes and other associated diseases, offering comprehensive metabolic benefits that significantly exceed those achieved with pharmacological therapy alone, always within the framework of a continued commitment to healthy lifestyle habits.

Content developed by Dr João Maia Teixeira, General Surgery, HPA Saúde