act to delay gastric emptying, and thereby induce meal termination: satiation. 11 Another peptide which is involved in the regulation of appetite is ghrelin. This hormone stimulates appetite, 12 and is suppressed after digestion of fat. 7 Absorption of fat Short-and medium-chain fatty acids (SCFA and MCFA) are absorbed via passive diffusion, as unesterified fatty acids, or transported via anion exchange or monocarboxylate transporter 1 (MCT1) transporters into the enterocytes. 13,14 If the SCFA and MCFA are not stored or oxidized in the enterocytes, they are transported to the liver, directly via the portal vein. 14 Long-chain fatty acids (LCFA) and MAGs follow a different route of absorption. The apical side of enterocytes is covered by a gel-like layer, also known as the mucus layer. 15 Unesterified LCFA cannot easily cross this layer. However, the formation of micelles, together with bile salts and phospholipids, facilitates their transport over the mucus layer. 16,17 The uptake of fatty acids into enterocytes is believed to be mediated by membrane-associated fatty acid-binding proteins. 18 At the apical membrane, transport proteins, such as fatty acid transporter protein 4 (FATP4 (SLC27A4)), the scavenger receptor cluster determinant 36 (CD36), and scavenger receptor class B Type I (SCARB1) are expressed. 4,18,19 The fatty acids in the micelles can be transported into the enterocyte via those transport proteins (Figure 2). Once unesterified, fatty acids and MAGs cross the epithelial membrane, where they can have different fates. 20 A part of the fatty acids can be used for oxidation. 20 However, most of the fatty acids and MAGs will be reesterified into TAGs, by monoacylglycerol acyltransferase (MGAT) and diacylglycerol acyltransferase (DGAT). 4 After a high-fat diet a part of these TAGs can be stored temporarily in lipid droplets in the enterocytes. 21 Formation of TAGs stimulates the production of microsomal triglyceride transfer protein (MTP). MTP transfers TAGs to a newly formed apolipoprotein B48 (apoB48), which rescues it from degradation, and forms it into a pre-chylomicron. 22,23 Then MTP transfers other TAGs, cholesterol, phospholipids, and fat-soluble vitamins into this prechylomicron. 4,19 Subsequently, apolipoprotein A-IV (apoA-IV) is added to the chylomicron membrane, which allows the particles to get larger and assimilate more lipids. 22 Thereafter, the chylomicron moves to the Golgi system, via fatty acid binding proteins (FABPs), 19 where apolipoprotein A-I (apoA-I) is added. 19 After final processing, the chylomicron is secreted via the basolateral membrane of the enterocytes. 22 Since chylomicrons are large in size, they cannot be secreted into the capillaries of the intestine. Instead, they are directed to the lymphatic system. Postprandial metabolism of fat Chylomicrons enter the bloodstream via the thoracic duct. 18,24 Once in the systemic circulation, chylomicrons can deliver fatty acids to skeletal muscle tissue, adipose tissue, and other peripheral tissues. 24,25 These tissues express ...