You plan a study to measure postprandial absorption of dietary fats. Which measurement is the best direct indicator that lipid monomers have been absorbed into the circulation after a fatty meal?

• A. An increase in circulating chylomicrons and plasma triglyceride-rich lipoproteins, measured in blood samples after the meal, indicating intestinal absorption and lymphatic transport of reassembled lipids.
• B. A fall in serum glucose concentration, since fat absorption directly consumes blood glucose and therefore is inversely correlated with circulating sugars.
• C. A direct measurement of intact dietary triglyceride molecules in portal blood plasma shortly after eating, since triglycerides pass directly through the portal vein unchanged into the liver.
• D. A rise in fecal fat content immediately within 5 minutes of meal ingestion, as this reflects rapid absorption kinetics into the bloodstream.

Answer: (A)