The health effects of lipids must now be explored beyond their energy content and fatty acid profile. Indeed, fatty acids as unit elements of different molecules such as triacylglycerols and phospholipids are being organized in various supramolecular structures such as emulsion droplets, and incorporated in complex food matrixes. This short article reviews our recent studies on the impact of fat emulsified structure on postprandial lipid metabolism and fatty acid beta-oxidation in normal-weight and obese humans, leading to the concept of "fast versus slow lipids". We also show how the postprandial kinetics of lipid absorption can contribute to modulate metabolic endotoxemia, partly arising from interactions between dietary lipids and gut microbiota, and able to contribute to metabolic inflammation in obesity. Finally, we highlight the pro-or anti-inflammatory impact in mice of surface active agents used in food formulation to stabilize emulsions, notably phospholipids of vegetal or dairy origin, and different molecular carriers of long-chain n-3 polyunsaturated fatty acids. The interested reader will refer to our other recent publications and reviews on these topics for a deeper insight into presented concepts.