Electrolyte and lipid metabolism of lean fasting men and women

Total plasma lipid, cholesterol and free fatty acid was measured during a 4 day fast of 7 lean men and 7 lean women. Urinary excretion of sodium, potassium and creatinine was measured. All parameters of fat metabolism increased more rapidly in women when rate of fasting is defined by negative caloric balance rather than time. No sex difference was found in sodium or potassium excretion. The potassium to creatinine ratio was lower in lean fasting men than women.