Cardiovascular disease (CVD) is recognised as one of the main causes of death in the western world. LDL- cholesterol ('bad' cholesterol) and other lipids (fats) are important CVD risk factors. Apolipoprotein E (apoE) is an important transporter of fats in the blood. ApoE comes in E2, E3 and E4 forms, depending on your genetic make up. Approximately 60% of the UK population are E3/E3, 25% E4 carriers and 15% E2 carriers. There is some evidence to suggest that an E4 genotype may put you at modestly higher risk of CVD. Furthermore although very inconclusive previous studies have suggested that E4 individuals are slightly more sensitive to the LDL-cholesterol modifying effects of dietary fats (saturated fat, total fat, fish oil) showing slightly, greater reductions when low levels of these fat are consumed, and greater increases when high levels of these fat are consumed. Therefore, the aims of the Satgene study is to examine the impact of modifications in dietary total fat and saturated fat intakes, alone and in combination with fish oil supplement on LDL-cholesterol and other blood lipids, in individuals with an E3 and E4 genotype. The levels of total fat and saturated fat used in the current study are within the range observed in a typical UK population.