Energy gels are perfect for the first 4 hours of an ultra. After that, palate fatigue kicks in and the gut needs real food. This guide explains the science of flavour fatigue, the best real foods to bring, the 60/40 sweet-savoury rotation, and how to plan the switch in advance.

This guide is part of our Ultra-Trail Snowdonia fuelling master series — read the master guide first for the full UTS protocol, then come back here for the deep dive on this single piece.

Key points

  • Most athletes switch around hour 4 to 6 when palate fatigue kicks in.
  • Palate fatigue is the gradual aversion to sweet, repetitive flavours during long endurance events.
  • Salted boiled potatoes, peanut butter sandwiches, jam sandwiches, salted ham wraps, rice cakes, bananas (25g carbs each), Medjool dates (16g each), and salted crisps.
  • Up to 4 to 6 hours, yes.
  • Three rules: (1) train the gut on the foods you'll race with - test in long training runs first, (2) keep portion sizes small, (3) stick to low-fibre, low-fat options.

Why gels work — until they don't

Energy gels are perfect for the first half of an ultra. They deliver 25 to 50 g of fast-absorbing carbs in a small package, require no chewing, and travel light in race vests. For most athletes the first 3 to 4 hours of an ultra runs cleanly on gels plus drink mix.

After hour 4 something changes. The same gel that tasted fine at hour 2 starts to turn the stomach. By hour 6 most athletes can't bring themselves to take another. This isn't weakness - it's a documented physiological response called palate fatigue, and planning for it is the difference between finishing strong and DNF'ing on a remote ridge.

The science of palate fatigue

Palate fatigue happens for two reasons. First, taste receptors adapt: repeated exposure to a sweet stimulus reduces the receptor's response. The second gel tastes sweeter than the tenth gel of identical formula. Second, the brain conditions an aversion: it links 'sweet' with the discomfort of sustained effort, and that learned link survives even after the race.

Both effects are protective. The body is signalling that variety is needed - more importantly, that real food (with fat, salt and texture) would now serve better than another sweet sachet.

The 60/40 sweet-savoury rotation

The strategy ultra coaches use:

  • Hours 0 to 4: 60% gels and drink mix (fast carbs, easy to take), 40% solid food (energy bars like BAR50 for chew variety).
  • Hours 4 to 8: 50% real food, 50% gels and drink mix. Add salted potatoes and sandwiches at aid stations.
  • Hours 8+: 60% real food, 40% liquid calories. Drink mix becomes more important than gels as solids get harder to chew.

The rotation prevents palate fatigue from ever fully setting in. You're never on the same flavour for more than 90 minutes.

STYRKR GEL50 dual-carb energy gel for the first half of an ultra

Best real foods for ultras

What works in the back half:

  • Salted boiled potatoes — most aid stations have these. Take handfuls.
  • Peanut butter sandwiches on white bread — 30 to 40 g of carbs plus protein and fat for staying power.
  • Jam sandwiches — pure fast carbs, easy to chew.
  • Rice cakes — homemade or store-bought, lightly salted, with a dab of jam.
  • Bananas and dates — 25 g and 16 g of carbs respectively, low-fibre, fast-digesting.
  • Salted crisps — surprisingly effective for sodium plus calories.
  • Hot broth — at aid stations, broth replaces sodium and warms the gut on cold races.

Avoid: high-fibre breads, fatty meats, large portions, anything you haven't eaten in training.

When to plan the switch

Most ultras have predictable points where the switch makes sense:

  • The first major aid station after hour 4: take 10 minutes to eat real food rather than another gel.
  • Climb-to-summit transitions: chew on a bar or sandwich on the climb, sip drink mix on the descent.
  • Anywhere your stomach starts saying no: switch to real food earlier if a gel turns the stomach.

Plan the switch in advance — write it into the crew brief, mark it on your race plan. Don't wait until you've forced down a fifth gel and feel sick.

Aid station strategy: real food first

By hour 6 of an ultra, every aid station has the potential to be a turning point. Athletes who push through aid stations to 'save time' often pay for it 30 minutes later when they bonk.

The 3-minute aid drill in the back half:

  1. Drop pack, sit (or lean) for 60 seconds.
  2. Eat real food first — handful of potatoes, half a sandwich, broth. Sweet stuff later.
  3. Refill bottles with MIX+, top up SLT+ tabs.
  4. Pocket 1 to 2 gels for the next 60 minutes only — not the full segment.
  5. Move out within 3 minutes.

Final word

The athletes who finish ultras well aren't the ones with the most willpower — they're the ones who plan for palate fatigue before it arrives. Frontload gels and drink mix in the first 4 hours, then rotate in real food at every aid station from hour 4 onwards. Sweet at the start, savoury and varied as the race goes long.

This guide pairs with our Ultra-Trail Snowdonia fuelling master guide — the real-food rotation is one piece of the broader UTS in-race fuelling system.

Related deep dives in this UTS series

Read the master overview at How to Fuel for UTS Snowdonia: An Ultra Trail Guide.