The review looked at who was actually enrolled in obesity drug trials over the last 30 years. It found that most studies mostly included White, middle‑aged women with moderate obesity, while men, people of color, older adults, and those with very high BMI were left out. This means the published results may not fully apply to those missing groups.

Medications for obesity have been studied in various populations over the past three decades. We aimed to quantify the baseline demographic characteristics of BMI, sex, age, and race in randomised clinical trials (RCTs) across three decades to establish whether the population studied is representative of the global population affected by the disease. Clinical trials of 12 medications for obesity (ie, orlistat, naltrexone-bupropion, topiramate-phentermine, liraglutide, semaglutide, lorcaserin, sibutramine, rimonabant, taranabant, tirzepatide, retatrutide, and orforglipron) published from Jan 20, 1999, to Nov 12, 2023, were assessed through a systematic review for methodological quality and baseline demographic characteristics. 246 RCTs were included, involving 139 566 participants with or without type 2 diabetes. Most trials over-recruited White, female participants aged 40 years or older with class 1 (30·0-34·9 kg/m²) and class 2 (35·0-39·9 kg/m²) obesity; older participants, those with class 3 (≥40·0 kg/m²) obesity, non-White participants, and male participants were under-recruited. Our systematic review suggests that future trials need to recruit traditionally under-represented populations to allow for accurate measures of efficacy of medications for obesity, enabling more informed decisions by clinicians. It is also hoped that these data will help to refine trial recruitment strategies to ensure that future studies are relevant to the population affected by obesity.