Changes in plasma lipoprotein levels during a hiking expedition in South America

Eleven males participated in a hiking expedition over a period of 6 weeks during which they walked an average of 15 km per day, resting days included. The participants completed a seven-day estimated dietary record before and during the expedition. Their habitual dietary intake before the expedition was typical of a Western diet. During the expedition most animal products, with the exception of canned fish, were excluded from the diet. The dietary intake of fat and carbohydrate changed from 36.9% and 40.6% to 14.0% and 76.4% respectively. Cholesterol intake dropped from 557 mg to 92 mg. Mean plasma total cholesterol (TC) decreased from 190.9 mg/100 ml to 142.0 mg/100 ml. These changes were mainly due to changes in low density lipoprotein cholesterol (LDL-C). Although high density lipoprotein cholesterol (HDL-C) did not change, the ratio of HDL-C to TC increased significantly. It can be concluded that drastic dietary changes, together with increased physical activity and weight loss resulted in major plasma lipoprotein changes. The expected fall in HDL-C due to a high carbohydrate diet was counteracted by the increased physical activity and weight loss.