Energy gels for marathon training: carbs per hour and how to practice

Energy gels for marathon training, in one paragraph: aim for 30 to 60 g of carbohydrate per hour on long runs, build toward as much as 90 g per hour if you'll be racing beyond about two and a half to three hours, and practice every gel you plan to race with on your long runs first. Gels aren't magic. They're a convenient, measurable way to get carbs in while running. The skill is taking them on schedule without your stomach filing a complaint.

That skill takes months, not a race morning. Here's the guideline, the arithmetic, a way to build up, and what to do when your gut objects. If you want the long runs themselves scheduled around your job and your gym sessions, get a plan built around your week. The gel flavor is still your call.

One note up front: this is general practice, not a personal prescription. If you have diabetes, a GI condition, a history of disordered eating or anything else clinical, talk to a doctor or a registered dietitian before changing how you fuel.

Energy gels for marathon training: the guideline

The joint position stand from the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine gives a target of 30 to 60 g of carbohydrate per hour for sustained exercise lasting 1 to 2.5 hours, and up to 90 g per hour beyond about 2.5 to 3 hours (Thomas, Erdman and Burke, 2016). Burke et al., 2011 describe 30 to 60 g per hour as an appropriate target for longer events, and note that events over 2.5 hours may benefit from up to 90 g per hour.

For marathoners, that splits two ways:

• ›Long runs in training often sit in the 1 to 2.5 hour window, so 30 to 60 g per hour is the working range.
• ›The race itself runs past 2.5 hours for most people. The median marathon finish in RunRepeat's race data is 4:26:33. That's where the "up to 90 g" end comes into play, but only if you've trained your stomach for it.

The gel habit usually starts earlier than the marathon. If you're coming up through a half marathon plan that keeps your lifting, the long runs in that block are where the routine begins. Before any of it, there's the meal before you start: what to eat before a long run explained covers the breakfast that gels build on.

How many gels: the arithmetic

Gels vary a lot by brand, so read the label for grams of carbohydrate per gel. The tables below use a gel with 25 g of carbs as an example. If yours is different, redo the sums with your number.

Per hour

Per race, if gels are all you take

Those top-end numbers look absurd because, for gels alone, they kind of are. In real races the count drops because:

• ›Sports drink counts. A cup at each aid station is carbohydrate. Find out what your race serves and how much carbohydrate is in it.
• ›You don't start at minute zero. Most runners take the first gel somewhere around 30 to 45 minutes in, after a proper breakfast.
• ›You stop near the end. A gel in the last 15 to 20 minutes won't do much before the finish.
• ›Chews, drink mix and real food count too. Gels are one tool, not the rule.

Do glucose-fructose gels matter?

Some gels blend different carbohydrate types, often glucose (or maltodextrin) with fructose. Burke et al., 2011 say products containing special blends of different carbohydrates may maximize absorption at high intake rates, which is why they come up at the 90 g end.

The position stand is more cautious. It describes these "multiple transportable carbohydrate" products as aiming to increase total intestinal absorption, and notes that its evidence analysis found the evidence for benefits currently equivocal (Thomas, Erdman and Burke, 2016).

Practical read: if you're aiming near the top of the range, a blended product is a reasonable thing to try. If you're at 30 to 60 g per hour, the gel your stomach tolerates matters far more than the sugar chemistry on the back of the packet.

How to practice energy gels on long runs

Your stomach is trainable. Jeukendrup, 2017 reviews evidence that gastric emptying and stomach comfort can be "trained", that diet affects the gut's capacity to absorb carbohydrate, and that this kind of nutritional training likely reduces the chance or severity of GI problems. The position stand says the same thing in plainer terms: athletes should practice to find a refueling plan that suits their goals, hydration needs and gut comfort (Thomas, Erdman and Burke, 2016).

A simple progression most runners can follow:

1. ›Start when long runs pass an hour. Not earlier. A 45-minute run doesn't need a gel.
2. ›Begin at the bottom of the range, around 30 g per hour. One gel at 40 minutes and another at 80 is plenty to start.
3. ›Add a little every week or two if your stomach is happy. More gels, a sports drink alongside, or a slightly shorter gap.
4. ›Practice at marathon pace. Swallowing a gel at an easy jog and at goal pace are different experiences. Do it in long runs with marathon-pace segments.
5. ›Use the exact race product. Same brand, same flavor, same caffeine or not. If you plan to use the course's sports drink, buy it and train with it.
6. ›Write down what happened. Cramps, sloshing, bathroom stops, energy dips. Adjust next week.

By your last few long runs, you should be taking the race-day plan, at race-day timing, without thinking about it.

Gels, chews, drink or food?

It doesn't much matter where the carbohydrate comes from. It matters that you get it in and that your stomach knows it.

The position stand adds that choices high in fat, protein or fiber may need to be avoided during the event to reduce the risk of gastrointestinal issues (Thomas, Erdman and Burke, 2016). So the energy bar with nuts and seeds is a post-run snack, not a mile-18 snack.

Take gels with water where you can. Planning them near aid stations on the course map saves you swallowing a thick gel dry.

Caffeine gels

Many gels come with caffeine. Some runners like them late in a race. Others find caffeine and a nervous stomach a bad combination. Check the label for how much each gel contains, count your morning coffee too, and test caffeine gels on long runs before you trust them on race day. If you have a heart condition or are sensitive to caffeine, ask a doctor first.

Fueling before the gels

Gels top up a tank. Fill it first.

• ›Race week: every marathoner is out there for longer than 90 minutes, so a carb load applies. The rules for carb loading before half marathon races and marathons are the same: 36 to 48 hours of high carbohydrate with reduced training.
• ›The night before: a normal, carb-forward, familiar dinner at a normal time. What to eat the night before a race covers it.
• ›Race morning: a familiar carb breakfast, usually two to three hours before the start, the same one you've used before long runs.

If a half marathon is your tune-up race, what to eat before a half marathon uses the same routine at lower stakes, and it's a good place to test your marathon breakfast. Shorter races barely need gels at all, which is why what should I eat before running a 5K has a much shorter answer.

Lifting and long runs

If you lift, the long run is where your gel practice happens, so protect it. Don't put a heavy lower-body session the day before. Tired legs make everything feel harder, including your stomach at pace. Heavy legs earlier in the week, the day before the long run easy or off.

Beyond race day

Gels are race-day and long-run fuel. Your everyday eating does the heavier lifting across a build, and healthy eating for marathon training is mostly about eating enough carbohydrate on your biggest training days. After the race, eat something with carbs and protein once your stomach settles; what to eat after a marathon is mostly normal food in decent amounts for a few days. For shorter races, what to eat after 5K is just a normal meal, reasonably soon.

Common mistakes

• ›Never taking a gel in training. Then taking five in a race.
• ›Waiting until you feel empty. Start early, the way you practiced.
• ›Copying someone else's 90 g per hour. They trained up to it. You start at 30.
• ›Grabbing a new brand at the expo. No.
• ›Swallowing gels dry. Plan them near water.
• ›Forgetting the sports drink counts. You might be doubling up.

How exrsz handles marathon training

exrsz builds a periodized plan from your goal, your schedule, your level and your equipment, with running and lifting balanced in one plan, so your long runs, where you practice gels, land on fresh legs. It adapts each week to how you trained and reshuffles missed sessions. What flavor you choose is between you and your stomach.

FAQ

How many energy gels do I need for a marathon?

It depends on your finish time, the carbs in each gel and how much sports drink you take. The position stand targets 30 to 60 g of carbohydrate per hour, and up to 90 g per hour beyond about 2.5 to 3 hours if you've trained for it (Thomas, Erdman and Burke, 2016). With 25 g gels at 60 g per hour, a four-hour runner would need about ten if gels were all they took.

When should I start using energy gels in marathon training?

Once your long runs pass about an hour. Start at the bottom of the range, around 30 g per hour, and build up gradually over the training block.

Can you train your stomach to handle more gels?

The evidence suggests yes. A review by Jeukendrup, 2017 reports that gastric emptying and stomach comfort can be trained, and that this likely reduces the chance or severity of GI problems.

When should I take my first gel in a marathon?

Most runners take the first one around 30 to 45 minutes in, then every 20 to 40 minutes depending on their target grams per hour. Use the same timing you practiced on long runs.

Do I need glucose-fructose gels?

Not necessarily. Burke et al., 2011 say blends may maximize absorption at high intake rates, but the joint position stand describes the evidence for benefits as currently equivocal (Thomas, Erdman and Burke, 2016).