Obesity, characterized by excessive accumulation and storage of body fat, is a chronic condition with far-reaching health implications (Obesity: preventing and managing the global epidemic. Report of a WHO consultation. World Health Organ Tech Rep Ser 894:i–xii, 2000). In medical practice, obesity is traditionally assessed using the body mass index (BMI), calculated by dividing an individual’s weight in kilograms by the square foot of their height in meters. This pivotal metric categorizes individuals into distinct ranges that predict their susceptibility to weight-related complications (Wells and Fewtrell, Arch Dis Child 91:612–617, 2006). Normative weight (BMI 18.5–24.9 kg/m2) entails minimal risk, while overweight (BMI 25–29.9 kg/m2) poses moderate risk, escalating with additional cardiovascular risk factors (Wells and Fewtrell, Arch Dis Child 91:612–617, 2006; Pasco et al. BMC Obes 1:9, 2014). Obesity (BMI ≥ 30 kg/m2) and severe obesity (BMI ≥ 40 kg/m2) underscore heightened risk (Wells and Fewtrell, Arch Dis Child 91:612–617, 2006; Pasco et al. BMC Obes 1:9, 2014). Notably, a BMI of 30–34.9 signifies moderate risk, while ≥35 translates to high risk (Wells and Fewtrell, Arch Dis Child 91:612–617, 2006; Pasco et al. BMC Obes 1:9, 2014). Complementing BMI, other methods like waist circumference, waist-to-hip ratio, and waist-to-height ratio synergize to holistically assess body composition, with BMI serving as the cornerstone for treatment decisions (Pasco et al. BMC Obes 1:9, 2014). The imperative for weight loss stems from obesity’s established role in exacerbating morbidity and mortality risks (Prospective Studies Collaboration et al. Lancet 373(9669):1083–1096, 2009). As BMI escalates, the likelihood of adverse health outcomes increases exponentially (Jensen et al. Circulation 129(25 Suppl 2):S102–S138, 2014). Obesity precipitates an array of complications, including hypertension, dyslipidemia, type 2 diabetes mellitus, coronary artery disease, stroke, gallbladder disease, and obstructive sleep apnea. Additionally, several cancers (endometrial, breast, colon, kidney, gallbladder, and liver), mental health disorders, osteoarthritis, low quality of life, body pain, and diminished functionality are commonly seen (Obesity: preventing and managing the global epidemic. Report of a WHO consultation. World Health Organ Tech Rep Ser 894:i–xii, 2000). Formulating efficacious weight loss strategies begins with a comprehensive history and physical, unraveling barriers that impede the prevention and reversal of obesity. While a multitude of determinants (age, gender, hormonal dynamics, socioeconomic status, medication-induced effects, etc.) intricately interplay with obesity, this chapter’s focus is on elucidating the relationship between obesity and prevalent pain disorders. The chapter encompasses an overview of obesity and segues into exploring its interconnectedness with fibromyalgia, low back pain, and pediatric pain. Subsequent sections unravel altered pharmacokinetics and pharmacodynamics of pain medications in obesity, the transformative potential of bariatric surgery in musculoskeletal disorders, and the pivotal role of dietary interventions in pain modulation (Jensen et al. Circulation 129(25 Suppl 2):S102–S138, 2014; Taylor Jr et al. Curr Pharm Des 20(38):6037–6041, 2014; Apovian, Am J Manag Care 22(7 Suppl):S176–S185, 2016; D’Onghia et al. Semin Arthritis Rheum 51(2):409–424, 2021; Pilková and Hartinger, Vnitr Lek 66(8):465–471, 2020; Speck et al. Surg Obes Relat Dis 10(1):161–170, 2014; Cuevas-Cervera et al. Int J Environ Res Public Health 19(11):6698, 2022).