Over the past few years, the guidelines around mid-run fuelling have moved quickly. The gold standard used to be 60g of carbohydrate per hour. Now, there’s talk of 90g or even 120g. In a new review, From Metabolism to Medals, researchers looks at whether the old fuelling recommendations are past their sell-by date.
The most relevant piece of data from the review comes from elite male marathoners. The runners, all of whom had marathon bests of sub-2:30, were asked to complete a two-hour treadmill run close to marathon pace while consuming 60g, 80g or 120g of carbohydrate per hour. The results broadly found that consuming 120g per hour led to a 3% improvement in running economy compared with consuming 60g per hour. However, there’s a drawback: consuming 120g of carbohydrate per hour led to a higher incidence of stomach issues.
There are other variables to consider, too. Exercise intensity, body size, training status and fuelling history all play a part. Consequently, 60-75g per hour may be best for some runners, while 90-120g may be best for others. Like running footwear, it’s an individual thing – there are no hard and fast rules.
That said, there are some broad conclusions that we can come to based off the data. In his Run Long, Run Health, Run Health newsletter, Brady Homer interprets the data like so…
Runs under 60 minutes0g per hour (so, no carbs) will usually be fine. Consider carbs only if the run is a) very intense, or b) done after fasting.Runs of 60–90 minutes 0-30g per hour for easy runs. 30-45g per hour for harder runs (like intervals or tempo runs) or race-specific work (like runs at marathon pace).Runs of 90 minutes to 2.5 hours 30-60g per hour for most runners. 60-75g per hour for harder long runs or marathon-specific workouts.Marathons 60-90g per hour for many marathoners. 90-120g per hour for gut-trained runners with a clear performance reason. Use glucose-fructose or maltodextrin-fructose blends, such as Maurten, when pushing above 60-70g per hour.Ultramarathons 60-90g per hour for many competitive ultrarunners. Higher intakes may be useful for some, but they require gut training and dutitious product selection. Mix it up with drinks, gels, chews and some low-fat, low-fibre solid foods.Related Story