The third randomized controlled clinical trial was the Fastingand Enhanced Expression of Longevity Genes during FoodAbstinence (FEELGOOD) trial (21). It used a Latin-squarecrossover design to examine just one 24-h period of fasting and1 day of ad libitum feeding. FEELGOOD is the only randomizedcontrolled trial of fasting to correct for multiple comparisons(21). No primary endpoint was used, but P # 0.00167 was thethreshold for significance for 30 tests of hypothesis. In FEELGOOD,fasting induced marked but temporary increases in humangrowth hormone (HGH), red blood cell count (and hemoglobinand hematocrit), and total cholesterol [resulting from increasesin both LDL cholesterol and HDL cholesterol, despite substantially decreased triglycerides, as found in other fastingstudies (41, 42)] (21). This trial evaluated only 1 day of fasting,and no safety outcomes were studied (21); thus, the findings areuseful primarily in developing longer-term trials.