INS and type 2 diabetes mellitus: Among insulin-users, one study reported a significant reduction in weight for the IF group (-4.77 ± 4.99 kg, <i>p</i> < 0.001).<h4>Conclusion</h4>IF represents an effective adjuvant therapeutic strategy in T2DM and could be widely employed in clinical practice.<h4>Systematic review registration</h4>Identifier CRD42025650065, https://www.crd.york.ac.uk/PROSPERO/view/CRD42025650065.