Antiretroviral therapy (ART) containing integrase inhibitors (INSTIs) and/or tenofovir alafenamide (TAF) has been associated with greater weight gain. Yet few studies have delineated between exposure to "anchor" drugs (protease inhibitors [PI], non-nucleoside reverse transcriptase inhibitors [NNRTI] or INSTIs) and exposure to nucleoside reverse transcriptase inhibitors (NRTIs). In this cohort of antiretroviral (ARV) naïve patients who initiated ART from 2008-2022, we analyzed body mass index (BMI) gain for 8 contemporary "anchor" drugs and 3 contemporary NRTIs during the first 3 years of ART. We censored patients if they stopped, switched, or added another ARV to their regimen. We used generalized estimating equations (GEE) to assess the association between BMI gain and choice of ART and a non-linear mixed model for the marginal coefficients of determination. We adjusted for time, baseline demographic and HIV-characteristics, and time-updated HIV and substance use related variables. 4,194 patients contributed 20,528 BMI measurements which were used for multivariable modeling. Most patients were black (55%) and male (77%). Median BMI gain over 3 years was +1.9 kg/m2 (IQR 0.1-4.1). ARV use accounted for only 9% of the predicted BMI change. Only efavirenz (EFV) and tenofovir disoproxil fumarate (TDF) were independently associated with (lower) weight gain while no differences between INSTIs, PIs, or rilpivirine were observed, nor between TAF and abacavir. The choice of initial ART had little impact on weight gain. INSTIs or TAF were not independently associated with weight change after ART initiation, but EFV and TDF were.