Recent studies suggest that the introduction of antiretroviral agents such as integrase strand transfer inhibitors (INSTI) may lead to weight gain in people living with HIV (PLHIV). In this retrospective observational study, we report the weight changes observed in virologically suppressed HIV patients after 12 months of switching to bictegravir/emtricitabine/tenofovir alafenamide (BIC/F/TAF) due to a national change in public policy in Mexico. Patients on prior regimens based on TDF/FTC or ABC/3TC plus non-nucleoside retrotranscriptase inhibitor, INSTI, or protease inhibitor were included. In the 399 patients analyzed, a significant weight increase was found, as well as an increase in body mass index (BMI), total cholesterol, low-density lipoprotein cholesterol (LDL-C), glucose, creatinine, and CD4+ cells after 12 months of switching treatment (all p ≤ .001). Mean weight gain was 1.63 kg [confidence interval (95% CI): 1.14-2.11], whereas the average percentage of weight gained was 2.5% (95% CI: 1.83-3.17). After considering the confounding effect of baseline weight status, the change in weight and BMI did not present significant differences between any of the prior treatment schemes. In conclusion, PLHIV switching to BIC/F/TAF therapy experienced weight gain after the first year of switching treatment. Although this weight gain could be due to the switch in treatment regimen, it cannot be excluded that it was caused by other factors since no comparable control group could be used for comparison.