Effect of prolonged fasting on plasma lipids, lipoproteins and apolipoprotein B in 12 physicians participating in a hunger strike: an observational study

Background: Dyslipidemia and obesity serve as risk factors for the developm ent of atherosclerotic cardiovascular disease. Fasting is sometimes recomme nded for treating these conditions. This study was undertaken to try to res olve conflicting results reported in the literature. Objectives: To study the effect of fasting (0 calories, with free intake of fluids) for 3-5 days on plasma concentration of triglyceride, cholesterol and apolipoprotein B. Methods: Physicians, about to begin a hunger strike, were divided into four groups: normolipidemic non-obese men (group 1), two moderately obese men a nd two men with type TV hyperlipidemia (group 2), healthy non-obese women ( group 3), and healthy non-obese women on oral contraceptives (group 4). Adh erence to fasting was monitored daily by detailed interviews, loss of weigh t, drop in plasma glucose, presence of ketonuria, progressive rise in serum creatinine and uric acid, and decrease in plasma pH. We monitored their se rum glucose, electrolytes, liver function, lipids, lipoproteins and apolipo protein B on days 0, 3, and 5. Results: Physicians who adhered to complete fasting lost more than 1.5% of their body weight after 3 days of fasting (n=12), and more than 3.2% at 5 d ays (n=5). All non-obese normolipidemic males and females (groups 1 and 3) showed an increase in plasma triglyceride (by 28-162%) and very low density lipoprotein cholesterol (by 22-316%) after 3 days of fasting. The obese an d hyperlipidemic men (group 2) showed a decrease of 17-63% in their VLDL ch olesterol, and the women on oral contraceptives (group 4) showed a 20% decr ease in their plasma triglyceride on day 3. Low density lipoprotein cholest erol increased by 13% in group 2, decreased by 7.3% in group 4, and remaine d unchanged in group 1 and 3. Apolipoprotein B level correlated well with L DL cholesterol in all groups. High density lipoprotein cholesterol changes were inconsistent. Conclusions: These results help to explain and reconcile previous published reports. The metabolic background of the individual together with the amou nt of energy consumed affect the behavior of plasma lipids and lipoproteins levels during fasting.