Milk fat droplets are coated by triple-layer of membranes containing numerous complex lipids (CL) like phospholipids and sphingolipids. CL functions to protect the droplet from coalescence and degradation, thereby modulating release of triacylglycerol molecules. CLs have important functional roles in the body as well. Here the role of CL-coated milk fat in early life and its potential impact on later life health is highlighted. Several intervention studies in early life have been conducted suggesting that supplementation of infant and mama formulas with CL is safe. In infants, CL supplements leads to improvements in cognition, fever incidence, and infectious outcomes including diarrhea and otitis media. Therefore, CL supplementation of infant formula may narrow the gap between breastfed and formula-fed infants. Furthermore, not only CLs matter, but also the size of the fat droplet matters. Large CL-coated fat droplets that mimic human milk prevented fat accumulation and improved the metabolic profile in adulthood in a preclinical model. Safety of this new concept has recently been demonstrated in infants and an efficacy study is currently ongoing. A proof-of-concept study in adults suggests that fats in an infant formula with larger and complex-coated fat droplets are more rapidly absorbed than those from a standard infant formula. These preliminary data suggest that exposure to a CL-coated milk fat structure in early life may be a key determinant of later life metabolic health.