Results of OMM2010 Nutrition Study

As part of OMM 2010 I took part in a nutrition study, run by Liz Mahon at Liverpool John Moores University.  I hope Liz will forgive any errors and oversimplifications, but here are the key messages I took from her report.



The trial was focussed on the effect of carbohydrate intake before and during the race. The 27 participants were split into two groups - the intervention group were instructed to consume additional amounts of carbohydrate in the week before the run. We logged all the food we ate before and during the event. When we got to the event we filled in questionnaires, gave a blood sample, and undertook some cognitive and physical tests, which were repeated at the overnight camp and at the end. 


Principal findings:


Carbohydrate consumption in the seven days before the event:

• Neither group managed to reach the recommended mean carbohydrate (gram per kilogram, body mass per day) of 6-10 g/kg/day. (That was despite me eating what seemed like a huge amount of carbs!)
• In terms of performance, carbohydrate consumption, and in particular day 7 (ie the day before the race) carbohydrate consumption, was positively associated with performance.
• Day 5 or 6 intakes of carbohydrate were not associated with performance, suggesting that carbohydrate loading may be effectively achieved in just one day, making such strategies easier to comply with.
• Those who consumed higher quantities of alcohol on day 7 tended to show lower pre-race blood glucose concentration.
• Those who consumed a higher percentage of energy from fat and protein tended to rate higher scores of tiredness – pre event.

Food consumed during the event:

• Carbohydrate consumption while out on the hill on day 1 was within the recommended 30 – 60 gram/hour rate.  However, the amount consumed was towards the lower end of this recommendation and so runners could benefit from increasing their carbohydrate intake. 
• The amount of energy, carbohydrate and protein consumed overnight at mid camp showed a strong positive correlation with overall and day 2 performance.  Therefore it appears that whilst intake during day 1 is not as important, intake during mid camp is important, as it is likely to affect recovery and replenishment of carbohydrate stores in time for competition on day 2.
• Those who consumed more carbohydrate also tended to perform better (or show less deterioration throughout the event) on several of the cognitive and physical tasks.  

General Conclusions

• There definitely appears to be at least some beneficial effect of increasing carbohydrate consumption both before and during such events.
• Many of the participants in the intervention group reported struggling to consume the amount of carbohydrate we recommended in the week leading up to the event, but these results suggest that by just increasing your consumption on the day before may have a positive effect on performance.
• These results also highlight the importance of recovery nutrition – in particular foods consumed during mid-camp on 2 day events.  It is recommended to consume carbohydrate and protein as soon as possible after exercise to enhance muscle recovery and replenish carbohydrate stores.

To sum that lot up (and so take even more liberties with Liz's carefully constructed scientific conclusions!):

• More carbs = good
• Carb loading is most effective in the 24 hours before the event.
• Make sure you take in the recommended amount of carbs while out on the hill
• Getting plenty of carbs and energy at the overnight camp is important to performance on Day 2.