After @ days on a fat-rich ( @ % @ % CHO , @ % @ % fat , and @ % @ % protein ) , CHO-rich ( @ % @ % CHO , @ % @ % fat , and @ % @ % protein ) , or habitual ( @ % @ % CHO , @ % @ % fat , and @ % @ % protein ) diet , @ trained adolescent boys ( @ years ) performed a @-minute constant run at @ % VO@peak to determine the respiratory exchange ratio ( RER ) during exercise and @,@-m running on an outdoor track .