I’ve been reading this new journal paper this week about marathon running and in-race nutrition. As my main body of work with clients tends to focus around weight loss, I was always under the impression that our bodies can intuitively tell us how much food we need.
Mindful eating and listening to body cues are what I tend to lean towards when it comes to weight loss programming. Naturally I thought the same might apply in sport.
Although, I would always crunch the numbers of carbohydrate grams per kilo of body weight per hour for my client athletes, for myself it was different. I’d do a half fast calculation before my half marathon or long course event, then on the day only half stick to it. Mainly because I thought I would be able to feel when I needed more carbs. I think on my half marathon events it wasn’t to my detriment, but on the long course I did feel sick and faint afterward. I may not have had enough?
Should you plan your marathon race nutrition?
When I stumbled across this journal paper  it was quite interesting. It tested if ad-lib carb (gel) consumption during a marathon by self-selecting your own nutrition during a race provides a better performance outcome. Compared to a nutrition stagey that has been scientifically based and individually customised.
Researches had two groups: The (FRE) group had to apply a freely chosen nutritional strategy in Copenhagen Marathon 2013 (CPH2013), while the other group (SCI) had to apply a scientifically based nutritional strategy in the same race.
Runners where paired according to height, BMI, age, running experience, estimated finish time and 10km time trial. There where 14 pairs in total, 7 in one group and 7 in the other.
It turns out that in the first 20km of the race both groups had equal results. Running velocity was the same, however after 21-25km that’s when the decline in performance occurred in the FRE group who only ingested 34g of carbs per hour. See graph below from study paper .
What can be learnt from this study is that runners who used a freely chosen nutritional strategy consumed considerably less carbohydrate than runners applying a scientifically based strategy, who consumed on average 64g carbs per hour. This resulted in a significant difference in race times. Finish time for runners in the SCI group was 10:55 ± 13:09 min shorter than for runners in FRE. Essentially the SCI group performed on average 5% faster due to having double the amount of carbs. That difference in time is nothing to sneeze at, imagine taking first place with a lead of 10min? Crazy stuff!
The take home message is if you are doing a long distant event, it’s probably best to get your needs calculated and planned by a sports dietitian. Scientifically based nutritionist strategies work and produce better performance outcomes. And most of all if you are going to make all that effort in training and getting a nutrition program, then follow it on the day! Case in point for me, I don’t know if its laziness or I think I am beyond “following the rules”. I should just follow my own advice and stick to the damn plan!
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