The study was conducted in controlled medical environment of the Orthopedic Hospital of Valdoltra, Slovenia. The participants were housed in standard air conditioned hospital rooms and were under constant surveillance with 24-hour medical care. For 14 days, the participants performed all daily activities in bed and received eucaloric controlled meals three times a day. Dietary energy requirements were designed for each subject multiplying resting energy expenditure by factors 1.2 and 1.4 in BR and ambulatory period, respectively. The resting energy expenditure was calculated as done in previous studies. The macronutrient food content set at 60% of carbohydrates, 25% fat, and 15% of proteins, according to the scheme of the so called "mediterranean diet" and adopted also in previous bed rest protocols. Energy balance was checked weekly by fat mass assessment. The daily protein intake was 1.1-1.25 g kg-1 in both groups, in BR and recovery period respectively, except the subgroups of OM who received a supplementation (see below).