Human subjects were used to test the effects of two simple diets of varying fat content on thiamine excretion. plasma cholesterol, ketone excretion and the oxygen cost of exercise. After subsistence on the high fat diet (60% of Calories) for two weeks, the subjects basal excretion of thiamine and their load dose returns of urinary thiamine were significantly less than on the low fat diet (18% of Calories). This was considered to be evidence that a high fat diet ha.s a sparing effect on the thiamine requirement of humans.
In the 2-week period plasma cholesterol levels were significantly increased by subsistence on the low fat diet; no change was observed when the subjects ate the high fat diet. These effects were attributed to the predominately saturated nature of the fat in the low-fat diet, in contrast to the high fat diet in which 69% of the fat was unsaturated corn oil. No changes were observed in ketone excretion or in the oxygen cost of exercise during these experimental periods.