The present invention relates to monitoring of lipid metabolism and is, particularly, directed to a test for estimating the individual susceptibility of a subject to the effect of oxidized dietary lipids. A high calorie and high fat meal were given to subjects and postprandial levels of oxidized low-density lipoproteins (LDL) were measured in the plasma of the subjects, indicating susceptibility to atherosclerotic events and insulin resistance. Food were also analysed for peroxide lipid content indicating LDL oxidizing potential of said foodstuff in a subject after consumption.