Lipid patterns were determined in 167 healthy subjects in the age group 28 to 50 years living in an urban area, a suburban area and two rural areas to determine a possible relationship between their serum lipid patterns and food habits. Total cholesterol, high density lipoprotein (HDL)-cholesterol, and triglyceride concentrations were determined in the sera of fasting subjects, and low density lipoprotein (LDL)-cholesterol concentration was calculated. Risk of coronary heart disease as assessed by the body mass index, ratios of total cholesterol to HDL-cholesterol, and LDL-cholesterol to HDL-cholesterol, was significantly lower in subjects in rural area 2, who were agricultural workers with a high degree of physical activity, subsisting on a diet consisting mainly of plant food, despite a higher consumption of coconut, a saturated fat. It is possible that the hypercholesterolaemic effect of saturated fats was mitigated by the high fibre content of their diets.