Can't Eat Mid-Race? Nausea, Appetite Loss and How to Keep Fuelling

Written by James Frost, founder of Flaming Phoenix. I am not a doctor or a dietitian, and anything severe or persistent belongs with one. Updated October 2026.

Quick answer: Not being able to eat mid-race is usually one of two problems. Either your stomach cannot accept food, because hard effort diverts blood away from the gut, or your appetite has switched off. For both, ease the pace for 5 to 10 minutes, sip water, then restart with very small, frequent bites of something bland, salty or drinkable.

It is one of the most common ways a well-trained runner's race unravels. When Stuempfle and Hoffman surveyed 272 runners after the 161km Western States Endurance Run, almost all of them had some gut symptom, and nausea was the complaint most likely to change how they raced. It was worst in the hottest, hardest part of the course. The table shows what they reported.

An earlier survey of 500 runners at Western States and the Vermont 100 by Hoffman and Fogard (2011) found the same thing from the other side: nausea or vomiting was the main reason non-finishers gave for dropping out (23%).

Why do I feel sick when running hard?

You feel sick when running hard mainly because blood is sent to your muscles and skin and away from your gut, so the stomach empties slowly and the intestine absorbs less. Heat, dehydration, a fast pace and over-concentrated sugar all make it worse.

A review in the American Journal of Physiology describes how this redistribution of blood flow significantly reduces supply to the gut and impairs the uptake of fluid, electrolytes and nutrients. A systematic review by Costa and colleagues found that gut injury, slower gastric emptying and malabsorption rise with intensity and duration, with about 2 hours at 60% of maximal aerobic capacity as the point where significant disturbance tends to appear. Heat and running, as opposed to cycling, both made things worse.

Four things push you over the edge, and most are in your control:

• Pace. Going out hard diverts the most blood. The first hour of an ultra is where many runners set up their stomach trouble for hour eight.
• Heat and dehydration. The International Society of Sports Nutrition (ISSN) ultra-marathon position stand notes that dehydration and a raised core temperature can further slow gastric emptying.
• Too much sugar at once. Glucose is absorbed through a transporter that tops out at around 60g an hour, according to Asker Jeukendrup; past that, sugar accumulates in the gut instead of being absorbed.
• Painkillers. The ISSN links frequent use of anti-inflammatory painkillers such as ibuprofen to kidney side effects in endurance events, and more than half of finishers in the Hoffman and Fogard survey were using them. Avoid relying on them to get through a race.

Why has my appetite disappeared?

Your appetite disappears because hard exercise lowers the hormone that drives hunger and raises the ones that signal fullness, and because sweet race food becomes repulsive after a few hours. Hunger will not come back until you stop, so you have to eat on a timer.

A meta-analysis of 20 studies by Schubert and colleagues found that a bout of exercise suppressed acylated ghrelin, the hunger hormone, by a median of 16.5%, and raised the fullness hormones PYY and GLP-1 by about 9% and 13%. The effects are small to moderate, but stacked on top of fatigue and heat they explain why you can be hours behind on calories and feel no hunger at all.

Taste fatigue does the rest. The ISSN reports that runners found sweet foods, gels and sports drinks especially, unpalatable in hot races and in races over 60 miles, and turned to savoury food. Will Grimshaw described exactly this late in the Dukeries 40: "I was struggling at that point and pretty sick of sweeter products, so the fact that the Phoenix bars are not too sweet was a bonus for my stomach."

How do you keep fuelling when you feel sick mid-race?

Slow down first, then restart small. Ease the pace or walk for 5 to 10 minutes to send blood back to your gut, cool off if it is hot, sip plain water, and then take a mouthful every few minutes rather than trying to catch up in one go.

1. Walk the next climb, or ease to a pace you could chat at.
2. Cool down if it is warm: shade, water over your head and neck, a looser layer.
3. Take small sips of water, and stop adding food for a few minutes if your stomach feels full.
4. Restart with tiny amounts: a sip of flat cola, a spoon of soup, one crisp, a thumbnail of bar.
5. Change the format if solids will not go down: soup, flat cola, a milky drink, or a bar stirred into hot water as a runny porridge at a checkpoint.
6. Add salt, especially in the heat. The ISSN suggests 300 to 600mg of sodium an hour in hot conditions.

The table matches what you notice to the most likely cause. It is a rough guide built from the sources on this page, not a diagnosis.

Flat cola is the classic aid-station rescue because it is sweet, cold and drinkable: CoFID lists cola at 10.9g of carbohydrate per 100ml, so a 150ml cup gives about 16g. It has almost no salt, so pair it with crisps or soup.

Why do I feel sick after running?

Feeling sick after a run usually has the same causes carried past the finish line: a gut that has been short of blood, a hard last effort, and heat or dehydration. Walk for a few minutes rather than stopping dead, sip water with a little salt, and eat something small and bland once the nausea eases.

Feeling sick is also one of the signs of heat exhaustion listed by the NHS, along with dizziness, headache, cramps and a high temperature. The NHS advice is to get somewhere cool, drink plenty of water, cool the skin and expect to feel better within 30 minutes. If you are often sick after ordinary runs, or the nausea lasts for hours, speak to your GP.

How do you stop it happening next time?

Most race-day nausea is preventable with pacing, practice and variety. Train your gut, race at an effort you can digest at, and carry a mix of sweet, savoury and drinkable options.

The gut is trainable. In Training the gut for athletes, Asker Jeukendrup reviews evidence that stomach comfort and gastric emptying improve with practice, and that a high-carbohydrate diet increases the gut's capacity to absorb sugar. Rehearse your race fuelling on long runs, at race pace, for weeks beforehand; the method is in gut training for ultras. The ISSN also advises a familiar, easily digested pre-race meal without much fat or fibre.

Build a flavour rotation: five to seven foods you know you tolerate, split between sweet and savoury, so you always have something to turn to. If you are choosing a bar for late in a race, the best energy bars for ultra running compares the main options; if gels are the problem, the energy gel alternatives guide converts each food into gel-sized portions. Dense, low-volume foods such as soft high calorie bars help when you can only manage a little: the high carb snacks guide ranks snacks by carbohydrate, and the calorie-dense foods guide by calories per gram.

Phoenix Bars are one option for that rotation, not a remedy. Each has up to 557 calories in a compact, lightweight 120g bar, with up to 66g of carbohydrate, so a quarter of a bar is still about 130 to 140 calories. They come in six flavours, and stirred into hot water they turn into a porridge you can almost drink; see how to use Phoenix Bars and high calorie porridge. Several reviewers say they need water with them, so test them on long runs first. On the Spine Race, Matt Pilgrim found them an easy way to keep his calories up, "particularly later on in the race when I didn't want to eat sweet foods." A mixed pack from the shop is the simplest way to find which flavour suits you.

How this fits into a full race plan is covered in the ultra running nutrition guide, the trail running guide, the best foods for ultra running and, for very long expeditions, the ultra-endurance and expedition nutrition guide. If you fuel plant-based, the fibre angle is worth reading in vegan endurance nutrition, and at altitude, where appetite drops further, see high-altitude mountaineering nutrition.

When should you stop rather than push on?

Stop, or get help at the next checkpoint, if vomiting will not settle, you become confused, you feel worse the more you drink, or you have signs of heatstroke such as hot skin without sweating. These are not rough patches to run through.

The NHS treats heatstroke as an emergency: call 999 if someone is still unwell after 30 minutes of resting somewhere cool, or has a very high temperature, a fit or loses consciousness. Over-drinking is the other trap. The ISSN warns that drinking plain water aggressively can dilute blood sodium, which can be fatal, and recommends sodium in your fluids (500 to 700mg per litre) on long races. Most mid-race nausea is unpleasant but harmless and passes once you slow down; knowing the exceptions is part of racing long.

Questions about nausea and appetite on the run

Why do gels make me feel sick?

Usually because the sugar arrives faster than your gut can absorb it, especially at a hard pace or in the heat. Take gels with water, spread them out, try mixed-sugar gels, and practise in training. If they still turn your stomach, swap some for real food; the gel alternatives guide has gel-sized swaps.

Does running cause more stomach problems than cycling?

Often, yes. In a 2022 trial where 28 endurance athletes ran or cycled for 2 hours at the same relative intensity in 35°C heat, 44% of runners had gut symptoms against 25% of cyclists, although symptom severity was similar.

Is it nausea or am I bonking?

Bonking is running out of fuel: heavy legs, a sudden drop in pace and a low, foggy mood that lifts once sugar goes in. Nausea is your stomach refusing food. You can have both at once, which is why the fix starts with slowing down; the guide to hitting the wall covers the fuel side.

Should I pack anything different in my drop bags?

Yes: put savoury and drinkable food in the later bags, when your stomach is most likely to have turned, plus something you actually look forward to. The drop bag guide has a full packing list.

Can ginger help with nausea during a race?

I do not know of good evidence for ginger during races, so I would not count on it. Some runners simply find a sharper, less sweet taste easier late on, which is a matter of taste rather than treatment.

Sources: Stuempfle and Hoffman, gastrointestinal distress in a 161km ultramarathon (Journal of Sports Sciences, 2015); Hoffman and Fogard, factors related to completing a 161km ultramarathon (2011); van Wijck and others, splanchnic hypoperfusion during exercise (2012); Costa and others, exercise-induced gastrointestinal syndrome (2017); Schubert and others, exercise and appetite hormones (Sports Medicine, 2014); running versus cycling and gut symptoms (Journal of Science and Medicine in Sport, 2022); ISSN ultra-marathon position stand (2019); Jeukendrup, carbohydrate intake during exercise (2014); Jeukendrup, Training the gut for athletes (2017); NHS, heat exhaustion and heatstroke; McCance and Widdowson's CoFID 2021.