Nutrition for a first 50 km ultra-trail: the simple plan
In a 50 km trail race, most people spend 6 to 9 hours outside. At this duration, your reserves are no longer enough: what you eat and drink on the go largely determines how you finish your race. The good news is that a simple plan, repeated during training, does almost all the work.
How it differs from a marathon
- Duration. You will be fueling for twice as long, so fatigue from sweetness becomes a real issue.
- Intensity. It is lower, which makes digestion easier and allows for solid food.
- Terrain. Climbs are hiked: these are your best opportunities to eat.
- Self-sufficiency. Aid stations are spaced out, sometimes by two hours.
Your three hourly targets
| What | Hourly target | Reference |
|---|---|---|
| Carbohydrates | 60 to 90 g | For a first 50 km, 60 g/h well tolerated is better than 90 g/h that makes you sick |
| Liquid | 400 to 800 ml | Depending on your thirst, heat, and sweat rate |
| Sodium | 300 to 800 mg | Towards the high end if it's hot or you sweat a lot |
Over 7 hours at 60 g/h, you will consume about 420 g of carbohydrates. That's a lot, and that's normal.
A sample plan
- Liquid base: a 500 ml flask with two servings of drink per hour, i.e., 60 g of carbohydrates and 680 mg of sodium with ELIXYR Endurance Fuel.
- Second flask: water, to drink according to your thirst and to rinse your mouth.
- Solids every 60 to 90 minutes starting from the 2nd hour: a small salty bite to break the sweet taste. If you add carbohydrate-rich solids, reduce your drink intake slightly.
- An alarm every 20 minutes on your watch. After four hours, you forget to eat.
To balance liquid and solid, read Liquid carbs vs. solid carbs.
Managing aid stations
- Study the course. Note the distance and especially the estimated time between each aid station.
- Prepare individual sachets of powder, one per flask to be filled. You just have to pour and add water.
- Keep a routine: refill flasks, grab something salty, head back out. Three minutes is enough.
- Beware of new things. Salted potatoes, bananas, and pretzels are safe bets; a product you've never tried is not.
When things get complicated
- Nausea: slow down, walk for a few minutes, switch to water and small sips. Resume carbohydrates as soon as it settles, even at half-dose.
- Disgust with sweets: alternate with salty food and dilute your drink further.
- Sudden slump: it's almost always a lack of carbohydrates. Take 30 g immediately.
Our article on stomach issues while running details the causes and solutions.
The weeks before
Your stomach trains just like your legs. On your long runs, eat and drink exactly as planned for the race, with the same products, the same bag, and the same pace. Aim for at least four to six complete repetitions. The details are in How to train your body to consume more carbohydrates.
Your list for race day
- Two 500 ml soft flasks.
- One sachet of powder per planned refill, plus two spares.
- Two or three salty snacks.
- A plan written on a piece of paper: what to take, at which aid station.
The ELIXYR Endurance Fuel provides 30 g of carbohydrates and 340 mg of sodium per serving, in a 2:1 ratio with HBCD. At 5.3¢ per gram of carbohydrates, you can use it for every long run, not just on race day.