The ADVANCE clinical trial compared three recommended first-line regimens two containing dolutegravir head-to-head and demonstrated virological non-inferiority at 48- and 96-weeks respectively1,2, paving the way for the mass- introduction of dolutegravir-containing regimens across low- and- middle-income countries. The dolutegravir-containing regimens in ADVANCE were very well tolerated and demonstrated remarkable viral re-suppression in patients with viraemia when adherence measures were instituted, even in the presence of genotypically-documented resistance1,2. Across Africa, including South Africa, and in many other low- and middle-income countries, the combination of tenofovir disoproxil fumarate/lamivudine (or emtricitabine) /dolutegravir has been rolled out to millions of patients, much of this with Unitaid support to research, programmes and communities. Most ADVANCE patients have since transitioned out of the study and are on tenofovir disoproxil fumarate/lamivudine/dolutegravir in South African public sector clinics in central Johannesburg. One of the unanticipated findings of ADVANCE and the concomitant Unitaid-supported NAMSAL3 study in Cameroon, as well as analyses of registration studies and observational studies, was the consistent finding that patients on dolutegravir experience significant weight gain and new-onset obesity. It remains unclear whether this is a feature of the integrase inhibitor class (and aggravated by tenofovir alafenamide), or whether other factors are at play - it is possible that HIV infection itself may predispose to weight gain in successfully treated patients, and other antiretrovirals may alter weight trajectories. The signal has been met with alarm by the public health community, as many countries where TLD is being rolled out are experiencing a parallel obesity epidemic. Obesity is strongly associated with adverse outcomes, including diabetes, cardio-vascular-disease (CVD), sleep apnoea, gastrointestinal and muscular-skeletal disorders, asthma, poor pregnancy outcomes, many cancers, mental health issues, and poor COVID-19 outcomes. In many countries with large antiretroviral programmes, these concurrent epidemics have significant public health and financial implications, and clarification of the extent of the obesity signal is urgent.