The Effect of Dietary Fat Modification on Risk Factors Associated With the Metabolic Syndrome

Inclusion Criteria: * Gender: males and females (not pregnant or lactating). * Body Mass Index (BMI) 20-40 kg/m2 * Total cholesterol concentration equal to or \< 8.0 mmol/l. * Medications / nutritional supplements allowed, on condition that the subjects adhere to the same regimen during the intervention: anti-hypertensive medication (including beta-blockers), oral contraceptives, hormone replacement therapy, multi-vitamin supplements, other non-fatty acid based nutritional supplements (e.g. garlic, anti-oxidants, etc). * Smokers and non-smokers. * Regular consumers of alcohol, which is not excessive as defined by elevated liver enzymes (AST and ALT). * Ethnicity: Intention to include white Europeans. Exclusion Criteria: * Diabetes or other endocrine disorders. * Chronic inflammatory conditions. * Kidney or liver dysfunction. * Iron deficiency anaemia (haemoglobin \< 12g/dl men, \< 11g/dl women) * Prescribed hypolipidaemic medication * Prescribed anti-inflammatory medication * Fatty acid supplements including fish oils, evening primrose oil, etc. * Consumers of high doses of antioxidant vitamins (A, C, E, beta-carotene). * Red rice yeast (Monascus purpureus) supplement usage. * High consumers of oily fish (\> 2 serving of oily fish per week of herring, mackerel, kippers, pilchards, sardines, salmon, trout, tuna (fresh), crabmeat or marlin). One portion is defined as a small herring or mackerel, one can of salmon or sardines or one salmon or tuna steak. Tinned tuna is permitted as it contains only minor amounts of long chain n-3 PUFAs. * Highly trained or endurance athletes or those who participate in more than 3 periods of intense exercise per week. * Volunteers planning to start a special diet or loose weight (e.g. the Slimfast Plan, Atkins Diet etc). * Weight change equal or \>3kg within the last 3 months. * Alcohol or drug abuse (based on clinical judgement). * Pregnant / lactating females / women planning a pregnancy in the next 12 months. Women who become pregnant during the dietary intervention period should be removed from the study.