Lipid mobilizing activity in the blood of obese patients during prolonged fasting.

Lipid mobilizing activity is lowered in the serum of obese patients. During short-term fasting, this activity increases in non-obese subjects. The present study was concerned with the changes in lipid mobilizing activity in the blood of obese patients during prolonged fasting, and with the behavior of esterified and free fatty acids. Serum levels of free fatty acids in the control subjects were significantly lower than in the obese women. During a 14-day period of complete fasting, levels of free fatty acids increased in all cases. In non-obese subjects this was accompanied by a significant rise in lipid mobilizing acitivity, but in obese subjects no significant change took place in this activity. The findings indicate that high levels of free fatty acids in obese persons during fasting are caused by inhibition of their esterification.