1. Diets containing 45% joules as fat, 45% joules as carbohydrate and 10% joules as calcium caseinate were given for 5 days to ten men and seven women. The fats used were sunflower seed oil or cream, and the carbohydrates were either glucose and fructose, glucose and raw starch or fructose and raw starch.
2. Sunflower seed oil in the diet resulted, after 5 days, in a significant fall in the concentration of triglyceride, cholesterol and phospholipid in the serum taken from subjects fasted for 12 h irrespective of the carbohydrate mixture of the diet.
3. Although there were changes in serum lipid concentrations in relation to the different mixtures of carbohydrate they were much less than those seen after ingesting sunflower seed oil.
4. Men and women differed in their response to carbohydrates, but this distinction was not seen in response to dietary fats.