Alan Aragon Research Review Highlights
Saturday, September 01, 2012
- Fat loading over carbohydrate loading before workout did not improve performance and actually caused gastro intestinal discomfort during workouts for cyclists.
In the latest trial to use this type of combination protocol, Havemann’s team observed better sprinting performance after 6 days of 68% carbs than on 6 days of 68% fat prior to the carb- load day (8-10g/kg).7 The sprints were interspersed at several points throughout a 100 km course, mimicking real-life competition conditions. In light of these findings, Burke and Kiens summarized the state of affairs as follows:9
“It is tempting to classify endurance and ultraendurance sports as submaximal exercise, which might benefit from increased fat utilization and a conservation of limited endogenous carbohydrate stores. However, the strategic activities that occur in such sports, the breakaway, the surge during an uphill stage, or the sprint to the finish line, are all dependent on the athlete's ability to work at high intensities. With growing evidence that this critical ability is impaired by dietary fat adaptation strategies and a failure to find clear evidence of benefits to prolonged exercise involving self-pacing, it seems that we are near to closing the door on one application of this dietary protocol.”
MCT is perhaps the most studied during-training fat. Once again, we must credit Jeukendrup and Aldred for reviewing the research dating back to 1995.12 Doses ranged from 30-116g one hour prior to training, and at 15-minute intervals during training. Durations were 120-180 minutes, and intensity (excluding time trials) ranged from 57-60% VO2max. Only one of the eight trials showed performance improvement and reduced glycogenolysis with MCT. Adverse gastrointestinal effects occurred in all subjects who consumed doses of 50g or more.
In more recent research, Goedecke's team had cyclists ingest either 32g MCT or 75g carbohydrate one hour prior to a five hour interval protocol ending in a time trial.15 During exercise, 200ml of a 10% carbohydrate solution or one containing 4.3% MCT and 10% carbohydrate was consumed every 20 minutes. Performance was significantly worse in the MCT group, half of which experienced gastrointestinal upset. If anything can be said about MCT’s track record – it’s consistent.
More to come...