Carbs on the move: how many grams per hour you really need

If you have been on social media lately, you will have seen professionals putting away 120 grams of carbohydrate an hour as casually as a bag of crisps. A scientific review published this year backs that figure… for the people who actually need it. The good news: if you are preparing for a sportive or an autumn half marathon, you can perform brilliantly on rather less, without turning your stomach into a cement mixer.

What the review proposes (and for whom)

A team from Liverpool John Moores University, led by Morton and colleagues, has reviewed in The Journal of Nutrition what we know about carbohydrate during endurance exercise. They propose moving the classic ceiling of 90 g per hour to a range of 90-120 g, with two very clear conditions: trained athletes and events lasting more than 2.5-3 hours. They also remind us of something anyone who has overdone the gels knows first-hand: high doses bring more gut trouble.

One detail worth knowing: several of the authors declare links with a sports nutrition brand (Science in Sport). That does not invalidate the review, but it is a good reason to read the 120 g with a critical eye rather than as an order.

Your figure depends on how long the event lasts

For amateur athletes, the consensus guidelines that have worked for years remain the best starting point. They are only a guide: your weight, your pace and your stomach have the final say.

And no, this does not contradict those who eat few carbs day to day: if you are curious, we went through what the Spanish Nutrition Society consensus says about keto, fasting and low-carb. Today is about what you eat while moving for hours, which is a different story.

From grams to real food

Nobody heads out with kitchen scales in their jersey pocket, so let us translate. Amounts are approximate (check the label where there is one):

A practical example: for a five-hour sportive aiming at 60 g per hour, one bottle of homemade drink every hour plus a medium banana, or a large date and a handful of raisins, would do the job. For a half marathon of two hours and a quarter, aiming at about 30 g per hour, one gel every 40 minutes from the first third of the race is enough.

Your stomach can be trained too

The message repeated most often in the research is that tolerance to eating on the move improves with practice. The gut adapts, but you have to ask it nicely and give it time, not on race day.

If you also use caffeine, remember it needs testing in training too: here we explain the coffee dose that actually works before training, because combining it with lots of gels can be too much for some stomachs.

Your autumn, with a full tank

If you are aiming for your first half marathon this autumn, the Artemis Challenge is exactly 21 km, and a great way to clock up long runs where you can rehearse your fuelling strategy. Reaching the finish full of energy, without visiting every portable toilet on the course, is also a victory.