How much energy do you need per hour?
Carbohydrates are key to keeping you going during the race. Count grams of carbohydrates from all food and drink combined. Grams of powder, number of packages, and kilocalories are other metrics.
Research doesn’t provide a single optimal number for all 100-mile runners. The 2019 ISSN ultramarathon guidelines suggest a conservative range of 30–50g of carbohydrates per hour, along with other energy. Broader endurance recommendations describe intakes of up to 90g per hour. Intensity, stomach tolerance, and race length all influence what works.
- If you are not used to eating while running: start training at about 40–60 g per hour, or the lower amount you already tolerate. Increase gradually. This is a starting point for training, not a ceiling for race day.
- If 60 g works stably during long sessions: try a plan within 60–90 g per hour during competition-like training. Then choose an amount you can handle even after many hours.
- Above 90 g per hour: requires special testing. Knowledge is still limited; 100–120 g is not a general requirement for completing 100 miles.
The ranges above are practical starting points. Being an elite exerciser does not automatically mean that your stomach can handle more, and a longer finish time does not mean that the energy can be skipped.
Three concrete examples of one hour of energy
Choose a schedule that you have already practiced. Start eating early, for example within the first 20–30 minutes, and spread your intake over the hour. An alarm every 20 or 30 minutes can help.
| Carbohydrates | Examples from the range | How to use the layout |
|---|---|---|
| 60 g/hour | 2 × Umara U Gel 30 g. | One gel approximately every 30 minutes. Plan the liquid separately. |
| 80 g/hour | 2 × Maurten Gel 160, 40 g each. | Spread it out over the hour. Also include carbohydrates from any sports drink. |
| 90 g/hour | 1 Tailwind Endurance Fuel Stick Pack, 50 g, + 1 Maurten Gel 160, 40 g. | Sip the drink and distribute the gel. Mix the drink according to the instructions; the composition also needs to suit your fluid needs. |
If you eat at a station, that food is included in the hour's total. Don't automatically add a full gel plan on top of sports drinks, cola and pit food. If you miss a meal: return to the plan with small portions instead of taking several gels at once.
Kullamannen, UTMB and UKA Pain – adapt to the course
Based on time between stations, weather and how easy it is to eat in the terrain. Our practical adjustments below are based on the organizers' course descriptions.
| Race | What affects the plan? | Practical customization |
|---|---|---|
| Kullamannen Ultra 100 Miles | Coastal environment, autumn darkness and technical sections at Kullaberg. | Have energy available with cold hands. Let some of the energy come from gels or food when you drink less in the cold. |
| UTMB | Alpine terrain with long climbs, downhill runs and large weather variations. | Calculate each distance in hours. Eat where the surface is safe and the effort allows it. |
| UKA Pain – Int Nod Dinghy 100 Miles | Hilly paths and recurring passages through the competition hub in Älvdalen. | Prepare clearly labeled refills for each passage, according to this year's rules for own energy and support. |
| Western States 100 | Mountains, long downhill stretches and risk of intense heat. | Practice energy in the heat and plan for cooling and hydration. Reduce effort when conditions require it. |
Always check the current course profile, station content, maximum times, mandatory equipment and support rules. A general energy plan does not replace the race PM.
Products to build your energy plan with
Combine formats according to taste, packaging and tolerance. A neutral gel can be suitable when sweet flavors are welcome, while puree or a smaller food portion can provide variety.
| Product | Carbohydrates | Function in the plan |
|---|---|---|
| Umara U Gel Neutral, 30 g Carbs | 30 g per gel. | Lightly flowing and caffeine-free. Easy to count in 30 g portions. |
| Ant Gel 160 | 40 g per gel. | Firmer hydrogel and larger amount of carbohydrates per package. No guarantee against stomach upset. |
| Enervit Carbo Gel C2:1PRO Sodium | 40 g per gel. | Also provides 200 mg of sodium. Count this in your other salt intake. |
| Tailwind Endurance Fuel Stick Pack - Lemon | 50 g per bag. | Caffeine-free sports drink with electrolytes. Follow the mixing instructions on the bag. |
| Maurten Drink Mix 320 | Approximately 80 g per bag. | Mix with 500 ml of water according to the instructions. Do not add everything on top of an already full gel surface. |
| Näak Energy Puree – Sweet Potato Pumpkin | 26 g per 90 g bag. | Heartier taste. Also provides fat and protein; test tolerance during running. |
| Bauuw Energy Puree – Banana/Kiwi/Vanilla | 15 g per 90 g bag. | Soft fruit puree for variety. Provides fewer carbohydrates per bag than the gels above. |
Compare carbohydrates, not just calories. The Näak puree provides 200 kcal but 26 g of carbohydrates because energy also comes from fat and protein. If you replace a 40-gram gel with it, the amount of carbohydrates will therefore be lower.
Glucose and fructose at higher intake
Mixtures of glucose or maltodextrin and fructose can facilitate high carbohydrate intakes because they utilize different transport pathways in the gut. Ratios such as 2:1 and 1:0.8 describe the mixture. No ratio guarantees that a particular dose will work for you.
Plan variety before you get tired of sweets
Feel free to alternate gels and drinks with small portions of foods you have tried: for example bread, rice, potatoes or soup with a carbohydrate-rich side dish. Broth can provide salt and fluid but does not necessarily provide much energy. Large amounts of fat, fiber or protein at once may be more difficult to tolerate during running.
We also have energy bars and waffles for those who prefer to chew. Read the current label: different flavors and versions may have different contents.
Fluid and salt need their own plan
Drink based on thirst and conditions, supported by what you have learned during training. A certain number of milliliters per hour does not suit everyone. Body size, pace, temperature and sweating change the need during the race.
If you need less fluid, more carbohydrates can come from gels or food. If you need more fluid, water can supplement the sports drink. Don't force yourself to drink extra just to reach a carbohydrate goal, and don't change the mix haphazardly.
Add up the sodium from sports drinks, gels, food and any electrolytes or salt tablets . 1 g of salt corresponds to approximately 400 mg of sodium. Concentration in mg/liter and intake in mg/hour are different measurements: 600 mg/liter gives 300 mg if you drink half a liter.
Salt tablets do not protect against overdrinking. Too much fluid can cause dangerously low sodium levels in the blood even when the drink contains salt. Therefore, more is not automatically better.
The days before the start and the meal before the race
Go into the race with a well-stocked energy supply. During the last one to two days, you can increase the proportion of familiar carbohydrate-rich foods and spread the food throughout the day: for example, rice, pasta, potatoes, bread and fruit that you can tolerate. Avoid trying to solve everything with a huge meal the night before.
Eat a well-balanced meal about three to four hours before the start and supplement with a small snack if necessary. For evening starts, breakfast and lunch also need to be planned. If you easily get stomach upset, less fiber and fat near the start may be easier to tolerate.
Drink normally before the race and avoid binge drinking. Race day is also not the right time to try new supplements.
Train your abs and the whole routine
Studies on runners show that repeated training with carbohydrates during activity can improve tolerance. This does not mean that all problems disappear or that an intake that works for two hours will certainly work for a day.
- Start with what you can handle. Repeat the same setup for several sessions. Then increase in small increments, for example 10–15 g per hour, if your stomach feels good.
- Test the combination. Try the same gels, drinks, food, mix strength and distribution that you intend to use in the race.
- Practice in a relevant environment. Wear a running vest and test your intake on hilly long runs and some runs in the dark. Don't add extreme workouts just to test your energy.
- Take notes. Write down grams per hour, fluid, weather, exertion, and when any problems begin.
Our sample packs of energy make it easier to compare flavors and textures before you buy for the whole race.
Calculate the packing between the stations
Carbohydrates to carry = estimated hours until next safe refueling × your hourly goal + reserve. Allow for darkness, altitude, fatigue, and the possibility that the route will take longer than planned.
Example: three hours to the next station
With a proven goal of 75g per hour, 3 × 75 = 225g of carbohydrates are needed. An extra hour of energy gives a total of 300g to carry. That is the amount of carbohydrates, not the weight of the pack.
A possible layer is two Tailwind Stick Packs of 50 g and five Maurten Gel 160 of 40 g: 100 + 200 = 300 g carbohydrates . Spread the intake over the distance and mix the drink according to the instructions.
Fluids are counted separately. If your tested estimate in similar weather is 500 ml per hour, the basic requirement in the example would be 1.5 liters for three hours, before reserves. Adjust the volume you carry according to the forecast, safe water points and the requirements of the race.
An hour's reserve is a rough estimate. Long distances and mandatory food reserves may require more. Don't assume that a favorite product will definitely be available at every station.
- Label bags for the stretch or depot with the amount of carbohydrates and possibly caffeine.
- Pack both a first choice and a tried-and-tested alternative with a different taste or texture.
- Decide what to eat at the station and what to take with you.
- Check remaining energy, fluid and time until next refill before you go.
For purchases, you can also calculate for the entire race: 30 hours × 60 g = 1,800 g of carbohydrates before reserves. Divide the total between what you carry, allowed drop bags and planned pit food. This is not a call to carry everything from the start.
Night, fatigue and caffeine
Keep a simple meal routine even at night. Labeled portion bags and a recurring alarm reduce the number of decisions when you are tired. A hot, familiar food portion at a station can provide variety if it is available.
Caffeine can reduce perceived exertion and increase alertness, but the effects and side effects vary. Plan it for selected parts of the race rather than choosing caffeine in every product. Test the dosage in training and also count coffee, cola and supplements.
Maurten Drink Mix 320 Caf 100 provides 100 mg of caffeine per sachet . That's 100 mg per serving, not per sip. Use caffeine-free alternatives during the rest of the race if you want to control the total.
EFSA lists up to 200 mg at a time and 400 mg spread over the day as levels of no general safety concern for healthy adults, with the exception of pregnancy, among other things. This is not a performance target or a safety guarantee for a long ultra-race . Use the lowest effective dose and keep track of your intake over the last 24 hours.
Caffeine is not a substitute for sleep. If you become so sleepy that you lose your orientation or cannot move safely, you need to stop and seek help from officials.
Backup plan when your stomach protests
For mild stomach upset: reduce the effort, eat smaller portions, and choose something simpler that you have previously tolerated. Temporarily stop heavy, fatty, or high-fiber foods and extra caffeine. Gradually return to the plan when you feel better.
Don't try to make up for a deficit by drinking a lot of concentrated drinks or multiple gels at once. Nausea can have many causes and is not a sure sign that you need more water or salt.
Seek medical attention at the race site if you experience repeated vomiting, severe headache, confusion, fainting, or if you are unable to retain fluids. Stop the race if you experience any obvious general effects; do not attempt to treat such symptoms with extra salt tablets and water.
After finishing: start with something you enjoy
Replenish carbohydrates, protein, and fluids at a leisurely pace. A smaller meal or snack may be easier than a large portion straight away. Continue to eat regularly during recovery and prioritize sleep.
If your appetite is low or food is delayed, recovery drinks and protein products can be practical supplements. The day's total food intake is more important than a specific product right after the finish line.
Frequently Asked Questions about Energy at 100 Miles
Do I have to consume 90 g of carbohydrates every hour?
No. Choose an amount that is tested for your intensity and stomach tolerance. Increase intake during training if necessary; race day is the wrong time to jump from a low intake to 90g.
Can I run 100 miles on just gels and sports drink?
It may work for some, but taste fatigue and appetite may change. Have a tried-and-true alternative with a different texture or flavor and factor its carbs into your plan.
Should I continue to eat when I go uphill?
Yes, slower speed doesn't mean energy can be skipped. Choose safe sections where the effort is low enough to eat and swallow comfortably.
How much energy should I have in the vest?
Calculate the estimated time until the next safe refueling times your hourly goal and add reserve. Also check the race's requirements for food reserve and fluid capacity.
Research background and limitations
The guide is based on sports nutrition, ultramarathon research and current product information. Schedules, packing examples and race adaptations are our practical applications. Much of the research is for shorter workouts than a 100-mile race; therefore, exact doses need to be tested individually.
- ISSN: ultramarathon nutrition (2019)
- Jeukendrup: carbohydrates during endurance work (2014)
- Plews et al.: the state of knowledge about very high carbohydrate intakes (2026)
- Costa et al.: abdominal training in runners (2017)
- Hew-Butler et al.: binge drinking and hyponatremia (2017)
- ISSN: caffeine and performance (2021)
- EFSA: caffeine and safety
- Thomas et al.: Nutrition and Athletic Performance (2016)
The advice is general for healthy adults. In case of illness, medication or recurring severe stomach problems, individual advice is needed. Race and product information checked September 28, 2026. Current packaging and the organizer's latest PM apply.
