diminished endothelial performance leading to SOB after a large fatty meal is more of an issue with people with a risk of cardiovascular disease. endothelial cells line blood vessels and their diminished performance leads to enhanced atherosclerotic change following a huge fatty meal (i've actually seen this in patients complaining of angina after large meals at mdcondald's). but at your age, unless you are at a very high risk of cardiovascular disease, is most likely due to your stomach increasing abdominal pressure and making it more difficult for your lungs to breathe. the association of high fatty meals in your case is most likely due to the fact that meals high in fat slow gastric emptying leading to a prolonged state of fullness. unless you're feeling pain along with SOB, i wouldn't worry about worse differentials like cardiovascular disease, hiatal hernias, etc.