Flavour fatigue in endurance sport: what to eat when sweet stops working
TL;DR: Flavour fatigue is the moment when, after hours of the same sweet taste, you can't get anything down while your body still needs fuel. You eat less and your finale suffers. The fix: vary texture and taste, keep your drink less sweet and bring something savoury on long days. Plan it upfront, not when it goes wrong.
Flavour fatigue is the moment when, after hours of the same sweet taste, you can't get anything down while your body still needs fuel. Your bottle stays full. The bar stays in your pocket. And you pay for it in the last hours. The overview of all your fuelling options is in my complete guide to energy bars for cycling. This one is about a single question: what do you do when sweet stops working?
What is flavour fatigue and why do you get it on long rides?
Flavour fatigue happens when you eat or drink the same taste for hours. After three or four hours of sweet drink mix, gels and bars, your head says: enough. Not because your tank is full, but because the taste puts you off.
The result is simple. You eat and drink less, right when you need carbs the most. The ISSN position stand for ultra runners (Tiller et al., 2019) therefore stresses that taste and tolerance matter, and that athletes crave more savoury food in longer races.
Why does a strong drink mix make it worse?
The sweeter and more concentrated your drink, the faster it puts you off. A strong mix also sits heavier in your stomach. Highly concentrated carbs are linked in research to more stomach issues during endurance sport (de Oliveira et al., 2014). More on that in stomach issues during exercise.
A drink that puts you off and sits in your stomach: that's the classic dip in hour three or four. How to combine sports drink and bar smartly is in isotonic sports drink with carbs: what works during exercise. Here I focus on taste.
How do you spot flavour fatigue before it's too late?
Flavour fatigue creeps in. Watch for these signs:
- Your bottle stays full: you drink less than planned without noticing.
- Aversion: the thought of another sweet sip or gel makes you queasy.
- Skipped feeds: you put off your bar until later, and later never comes.
- A sudden dip: your legs go empty while you thought you were doing fine.
What helps against flavour fatigue?
Variety. Not in how many carbs you eat, but in how they come in. This works:
- Vary texture: drink your carbs and eat them too. Chewing something solid is a different stimulus than yet another sip.
- Pick a fresher flavour profile: fresh acidity and spicy warmth wear off less quickly than pure sweetness.
- Bring something savoury: on days longer than four hours, a salty bite or a stop with bread or soup helps.
- Keep your drink lighter: drink a less sweet mix and get part of your carbs from solid food. That way you control how sweet it gets.
| Hour | Bottle | Why | |
|---|---|---|---|
| 1 | Sports drink | 1 bar | Everything still tastes good, start on time |
| 2 | Sports drink | 1 to 2 bars | Variety before fatigue kicks in |
| 3 | Lighter drink or water | 2 bars | Solid takes over part of the sweet drink |
| 4 and beyond | Water or light drink | 2 bars + something savoury | Salt and a different taste keep you eating |
How to build a plan like this for yourself, you'll read in building a fuel plan.
How many carbs do you need per hour, even when sweet puts you off?
Flavour fatigue doesn't change what you need. Up to 2.5 hours, 30 to 60 g carbs per hour is enough. Longer? Then 60 to 90 g per hour pays off, using a mix of glucose and fructose (Jeukendrup, 2014). My base stays the same:
- Sports drink: 500 to 800 ml per hour with 6 to 8% carbs, good for 30 to 60 g.
- Fruit performance bar: 1 to 2 per hour, each 20 g carbs in a 2:1 glucose/fructose ratio.
- Finale: possibly one gel at high intensity.
If the drink gets too sweet, shift part of it to solid food and drink a bit more water. Your total per hour stays the same. On rough terrain solid food has another advantage, see fuelling a long gravel ride. And the same applies in ultras, read whole food fueling in an ultramarathon.
Why didn't I make my bar sweeter?
Because sweetness alone wears off after three hours. My bar is fruit, with a fresh pear/lime flavour and ginger and cardamom for spicy warmth. 25 g, 20 g carbs, no artificials. Small enough to finish in two bites. Not a miracle cure for flavour fatigue, but a different taste and texture than your umpteenth bottle.
No gel. No brick. Fuel during exercise. Fuel your flight.
Scientific background
The ISSN position stand on ultramarathon highlights the importance of taste, tolerance and the growing preference for savoury food in longer races (Tiller et al., 2019). Highly concentrated carbohydrate solutions are associated with more stomach issues during endurance sport (de Oliveira et al., 2014). The recommended intake is 30 to 60 g carbs per hour up to 2.5 hours and up to 90 g per hour for longer efforts, using a mix of glucose and fructose (Jeukendrup, 2014).
Sources
- Tiller N.B. et al. (2019). International Society of Sports Nutrition Position Stand: nutritional considerations for single-stage ultra-marathon training and racing. Journal of the International Society of Sports Nutrition, 16, 50. doi:10.1186/s12970-019-0312-9
- de Oliveira E.P., Burini R.C., Jeukendrup A. (2014). Gastrointestinal complaints during exercise: prevalence, etiology, and nutritional recommendations. Sports Medicine, 44(Suppl 1), S79-S85. doi:10.1007/s40279-014-0153-2
- Jeukendrup A. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine, 44(Suppl 1), S25-S33. doi:10.1007/s40279-014-0148-z
Frequently asked questions
What is flavour fatigue during exercise?
Flavour fatigue is the moment when, after hours of the same sweet taste, you can't get anything down while your body still needs fuel. You drink and eat less than planned. Your carbs fall behind and your pace drops in the last hours. It mainly happens on rides and races longer than three hours.
When does flavour fatigue kick in?
Usually after three to four hours of using the same sweet drink, gels or bars all the time. The sweeter and more concentrated your drink, the sooner it happens. Heat and a sensitive stomach make it worse. Building in variety early helps you last longer.
Does a fruit performance bar help against flavour fatigue?
It helps, but it's no miracle cure. A solid bar gives a different texture than your bottle, and a fresh pear/lime flavour with ginger and cardamom wears off less quickly than pure sweetness. Combine it with a lighter drink and, on long days, something savoury.
Should I eat savoury food on long rides?
On days longer than four hours it often helps. Athletes crave more savoury food in long races. A salty bite or a stop with bread or soup breaks the sweet routine. You still get most of your carbs per hour from sports drink and bars.
How do I avoid eating too little in the last hours?
Plan your feeds upfront and stick to them, even when you're not hungry. Alternate drink and solid food, make your drink less sweet as the day goes on and bring something savoury. That way you hit 60 to 90 g carbs per hour, even in hours four and five.
