UTMB (Ultra-Trail du Mont-Blanc) Fueling Plan & Pace Chart

UTMB Fueling Strategy

UTMB is a different fueling challenge than American ultras. The European aid station model changes everything. Stations are well-stocked with hot soup, pasta, cheese, bread, Coke, and local foods. They feel more like restaurants than the grab-and-go style of US races. This is both an advantage and a trap.

The advantage: you have access to real, warm, calorie-dense food at regular intervals. The trap: runners sit down, eat a full meal, get comfortable, and lose 20 minutes they never get back. Your plan should include specific time limits at each aid station. Eat while standing. Refill bottles. Move.

The race starts at 6pm on Friday. The first major climb (La Charme to Col du Bonhomme) happens in darkness. Night climbing with a pack at altitude is not the time for aggressive gel intake. Eat real food before the start, carry easy-to-eat calories (rice cakes, bars), and sip a calorie drink on the climbs. Target 200-250 calories per hour for the first night.

UTMB's climbs are long and steep (2,000-4,000 feet of gain per climb). You'll be hiking, not running. This changes your fuel needs. Hiking burns fewer calories per hour than running but the efforts last longer. Steady, moderate calorie intake (200-300 cal/hr) beats the aggressive gel protocols used in flat marathons.

Altitude matters. The highest point (Grand Col Ferret, 8,323 ft) can cause appetite suppression even in acclimatized runners. Your body absorbs nutrients less efficiently above 7,000 feet. Plan to eat more at the lower-elevation aid stations and go lighter at altitude. Don't force it at the top.

The descents are where UTMB destroys stomachs. Hours of steep, technical downhill running rattles your GI system. Many runners who fueled perfectly on the climbs find they can't keep anything down during the long descents into Courmayeur or Champex-Lac. Liquid calories and flat Coke become essential backup options.

European gel brands differ from what you may train with. Maurten and SiS are widely available, but if you rely on GU or Clif, bring your own supply. Don't try a new gel brand at UTMB. The aid stations stock European brands and the flavors may not agree with you at hour 20.

The second night (Saturday into Sunday) is the hardest fueling window. You're 24+ hours in, sleep-deprived, and your gut is exhausted. Hot broth with bread becomes the most reliable calorie source. Have a crew member or drop bag with your preferred items at Champex-Lac (mile 80) and Trient (mile 88). The final climb over Catogne and the descent into Chamonix is where your discipline in the first 80 miles pays off.

Weather variability at UTMB is extreme. August temperatures can be 70°F in the valleys and near-freezing at the passes, sometimes with rain or snow. Cold conditions suppress thirst but not calorie needs. Carry a thermos of warm drink mix in cold sections. Hot fluid with calories is easier to consume than cold gel when you're shivering at 8,000 feet.