A backyard ultra gives you a fixed eating window: whatever is left of each hour after the 6.7056 km (4.1667 mi) yard. Plan food by that window and by yard number. For the rules and how the format works, start with the backyard ultra guide. If you have diabetes, kidney or heart disease, a history of disordered eating, or take medicine that affects fluid balance or alertness, build the plan with a clinician or sports dietitian.
Your Time Budget per Yard
The only backyard field study followed 12 male runners who completed an average of 34 ± 17 yards. Their average speed fell from 9.0 km/h at the start to 7.5 km/h at the end (De Pauw 2024). On a 6.7056 km yard, that changes the time left for base:
| Stage | Speed | Loop time | Time at base |
|---|---|---|---|
| Early yards | 9.0 km/h | ≈44.7 min | ≈15 min |
| Late yards | 7.5 km/h | ≈53.6 min | ≈6 min |
Early on you can sit and eat at base. Later, toilet, bottle and shoes take most of six minutes, so food has to move onto the course. Our base routine:
- On arrival, give crew one line: stomach, thirst, alertness.
- Eat the pre-portioned base dose (about 25 g carbohydrate) and pick up the on-course dose.
- Refill the bottle and use the toilet.
- Be in the start corral before the final warning. By day 2, keep the whole routine to 3 minutes or less.
How Much to Eat per Yard
A yard takes an hour, so the site-wide hourly carbohydrate tiers apply per yard. They come from the ISSN ultramarathon position stand (150–400 kcal, 30–50 g carbohydrate and 5–10 g protein per hour) and the intake studies:
- Floor: at least 30 g carbohydrate and 200 kcal per yard. In a Western States study, finishers ate 4.6 kcal/kg/h and non-finishers 2.5, about 320 vs 175 kcal/h at 70 kg (Stuempfle 2011).
- Default: 50 g per yard.
- Trained gut, racing for yards: 60–75 g per yard from glucose–fructose products. Three elite 100-mile runners averaged 71 ± 20 g per hour (Stellingwerff 2016).
- Ceiling: 90 g per yard. The ISSN says rates up to 90 g/h "may be unrealistic" beyond 6 hours, and Costa 2019 calls tolerance in ultras questionable.
Energy check. At the ISSN energy cost of 47.8–71.7 kcal per km, one yard costs about 320–480 kcal. Eating 200–250 kcal per yard leaves a deficit of roughly 100–250 kcal every yard, about 160–210 kcal for a 70 kg runner. That is expected. Do not try to close it by eating more at base; a large bolus is harder to run on than the deficit.
Per-Yard Plan and Loop Menus
This is our recommendation, built from the tiers above.
| Yards | Carbohydrate per yard | Energy per yard | How | Caffeine |
|---|---|---|---|---|
| 1–8 | 50 g: about 25 g on course, 25 g at base | 200–250 kcal | Gel or drink on course; banana, rice or half a sandwich at base; fluid to thirst | None |
| 9 to dawn | 40–50 g plus 5–10 g protein | 225–275 kcal | Savory food: rice in broth, salted potatoes, half a ham or cheese sandwich | About 50 mg per yard from nightfall |
| Day 2 onward | 30–50 g | 200–250 kcal | Soft or liquid food eaten while walking out; base routine 3 minutes or less | 1–2 mg/kg only when sleepiness returns |
| Any yard, floor | At least 30 g | About 200 kcal | Whatever stays down | — |
What that looks like in single yards (approximate values; check your labels):
- Cool daytime yard: one gel on course (25 g) and a medium banana at base (27 g): about 52 g and 205 kcal.
- Hot daytime yard: 500 mL of 6% sports drink on course (30 g) and 100 g of salted boiled potatoes at base (20 g): about 50 g and 200 kcal, with sodium from both.
- Night yard: 100 g of rice in broth at base (28 g) and half a ham or cheese sandwich eaten walking out (about 20 g carbohydrate, 5–10 g protein): about 48 g and 250 kcal, plus about 50 mg caffeine.
- Day 2 yard: 250 mL of cola (27 g) and a small pot of rice pudding (about 20 g), both taken walking out: about 47 g.
- Floor yard: a 237 mL bottle of a standard meal-replacement drink, often about 220 kcal and 33 g carbohydrate, sipped over the first half of the loop.
Pack sweet, savory, soft and liquid options for every phase; appetite does not change on a schedule. Keep perishables chilled and discard food that has sat out. Have crew log what you actually ate, not what was offered.
Protein: 5–10 g per Yard Overnight
The ISSN position stand includes 5–10 g of protein per hour in its racing range. We add it from yard 9 onward, when savory food is more appealing, as 5–10 g per yard on top of the carbohydrate, not instead of it. Approximate sources: 200 mL of milk (about 7 g), 100 g of Greek yogurt (about 10 g), half a ham or cheese sandwich (5–10 g), or a meal-replacement drink (about 9 g). Skip it in any yard where it makes the carbohydrate harder to get down.
Caffeine: How Much and When
The ISSN advises aiming caffeine at the later stages of an ultra and using repeat doses of 1–2 mg per kg (70–140 mg at 70 kg) rather than repeated 4–6 mg/kg boluses (280–420 mg). It describes about 50 mg per hour overnight as likely to be well tolerated. The ISSN caffeine position stand finds 3–6 mg/kg effective and reports frequent side effects at about 9 mg/kg (Guest 2021). For scale, three elite 100-mile runners reported 912 ± 322 mg across a whole race (Stellingwerff 2016).
- Day 1, daylight yards: none.
- From nightfall: about 50 mg per yard, such as half of a 100 mg caffeinated gel or about 125 mL of brewed coffee. A 10-yard night adds up to about 500 mg.
- Day 2: 1–2 mg/kg only when sleepiness returns, not every yard.
- Every source counts: label caffeinated food and drink at base so crew can keep the running total.
Test the products in training, and skip caffeine if it brings palpitations, tremor or worse nausea. It cannot replace sleep: if you are falling asleep on your feet or confused, the answer is in the red flags below, not another dose.
Fluid and Sodium per Yard
Drink to thirst, the default the hyponatremia consensus statement sets for preventing overdrinking. The ISSN range of 450–750 mL per hour is roughly one 500–750 mL bottle per yard, refilled at base, and less on cool night yards. Take 300–600 mg of sodium per yard, or 600–1,000 mg in heat. If you weigh more than at the start, you are overdrinking. The hydration and sodium guide has the sweat-rate test, the sodium arithmetic and the fluid warning signs.
Practice the Plan
Gut tolerance can be trained. In a randomized trial of 18 endurance runners, those who did a daily one-hour run for two weeks while taking 90 g of carbohydrate per hour had fewer GI symptoms and less malabsorption afterwards; the placebo group did not improve (Miall 2018). Our gut-training guide builds from 20 to 50 g per hour in 10 g weekly steps over four weeks, then confirms that level for two more.
- Rehearse 6–8 yards on a 6.7 km loop, once with a 15-minute base routine and once with a 6-minute one.
- Practice every planned food in its per-yard portion, including the night and floor options.
- Change one element at a time so you can tell what caused a problem.
- Do not start a restrictive low-FODMAP diet without qualified guidance.
Set Up a Simple Base
- Pre-portion by yard: bag base and on-course doses of about 25 g carbohydrate each, labeled with grams.
- Separate caffeine: keep caffeinated products in their own labeled box.
- Label food: ingredients, allergens and caffeine content.
- Protect food: use a cooler, covered containers, clean hands and clean utensils.
- Keep a log: grams eaten, fluid, caffeine and symptoms each yard.
The rest of the base, from chair and boxes to night light and power, is in the backyard ultra gear list.
GI Trouble and Red Flags
When nausea starts, walk the first part of the yard and drop to the floor of 30 g, taken as small sips: about 100 mL of cola every 20 minutes supplies roughly 32 g over the yard. Go back to the planned amount once two or three doses have stayed down. Do not force food after repeated vomiting.
For what ultrarunners eat more generally, see what ultrarunners eat during a race.
Sources
- De Pauw, K. et al. (2024) — Backyard running: Pushing the boundaries of human performance. European Journal of Sport Science, 24(10), 1432–1441.
- 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(1), 50.
- Stuempfle, K.J. et al. (2011) — Race diet of finishers and non-finishers in a 100 mile (161 km) mountain footrace. Journal of the American College of Nutrition, 30(6), 529–535.
- Stellingwerff, T. (2016) — Competition Nutrition Practices of Elite Ultramarathon Runners. International Journal of Sport Nutrition and Exercise Metabolism, 26(1), 93–99.
- Costa, R.J.S. et al. (2019) — Nutrition for Ultramarathon Running: Trail, Track, and Road. International Journal of Sport Nutrition and Exercise Metabolism, 29(2), 130–140.
- Guest, N.S. et al. (2021) — International society of sports nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition, 18(1), 1.
- Jeukendrup, A.E. (2017) — Training the Gut for Athletes. Sports Medicine, 47(Suppl 1), 101–110.
- Miall, A. et al. (2018) — Two weeks of repetitive gut-challenge reduce exercise-associated gastrointestinal symptoms and malabsorption. Scandinavian Journal of Medicine & Science in Sports, 28(2), 630–640.
- Hew-Butler, T. et al. (2015) — Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clinical Journal of Sport Medicine, 25(4), 303–320.
Frequently Asked Questions
How many calories should you eat per hour in a backyard ultra?
Plan on 200–250 kcal per yard, including 50 g of carbohydrate, and never less than 30 g and 200 kcal. A 6.7 km yard costs about 320–480 kcal at the ISSN energy cost of 47.8–71.7 kcal per km, so a deficit of 100–250 kcal per yard is expected and does not need to be made up. With a trained gut, 60–75 g of carbohydrate per yard is realistic; 90 g is the ceiling.
When should you use caffeine in a backyard ultra?
Not in the first daytime yards. From nightfall, take about 50 mg per yard, which the ISSN describes as likely to be well tolerated overnight. On day 2, take 1–2 mg per kg (70–140 mg at 70 kg) only when sleepiness returns. Avoid repeated 4–6 mg/kg doses; side effects are common around 9 mg/kg. Caffeine cannot replace sleep or treat confusion.
What should you eat during later backyard-ultra loops?
Soft or liquid food eaten while walking out: 30–50 g of carbohydrate per yard from cola, sports drink, gels, rice pudding or yogurt. In the only backyard field study, runners slowed from about 9.0 to 7.5 km/h, which cuts the time at base from about 15 minutes to about 6.
How much water should you drink during a backyard ultra?
Drink to thirst. The ISSN range of 450–750 mL per hour works out to roughly one 500–750 mL bottle per yard, and less at night. Add 300–600 mg of sodium per yard, or 600–1,000 mg in heat. Gaining weight means you are overdrinking, and sodium does not make excess fluid safe.
What is gut training for ultramarathons?
Gut training means practicing race-day carbohydrate during training runs so your gut learns to tolerate it. In one trial, two weeks of daily runs with 90 g of carbohydrate per hour reduced GI symptoms and malabsorption. Our gut-training guide builds from 20 to 50 g per hour in 10 g weekly steps over four weeks, then confirms that level for two more.