Plays an important role in the formation of lipid droplets (LDs) which are storage organelles at the center of lipid and energy homeostasis (PubMed:18160536, PubMed:22106267) (By similarity). Directly binds to diacylglycerol (DAGs) and triacylglycerol (PubMed:22106267) (By similarity). Predominantly expressed in skeletal muscle and at lower levels in the heart (at protein level). In the heart, mRNA expression levels do not correlate well with protein levels, suggesting post-transcriptional regulation in this organ. Knockout mice show no significant differences in heart size or function. Belongs to the FIT family. FIT1 subfamily.