Races start early, and the typical runner wakes, skips fluids, and lines up — already behind on the day's ledger. On a stone plan the fix is pre-hydration the night before and again in the hour before the start, so the race begins with a surplus rather than a deficit. This matters more than anything on the course, because a 5K is short enough that most people do not drink enough during it to catch up.
Race fuel is mostly the low-oxalate end of the scale, and the measured values make the standard runner food easy to keep:
| Food | Oxalate (mg) | Serving | Rating |
|---|---|---|---|
| Water, still | 0 mg | 1 glass | Safe |
| Sparkling water, plain | 0 mg | 1 can | Safe |
| Banana | 6 mg | 1 medium | Safe |
| Oatmeal, cooked | 2 mg | 1 cup | Safe |
| Apple, fresh | 2 mg | 1 medium | Safe |
Water carries no oxalate and is the race-day default. The banana is the runner's classic for a reason — 6 mg of oxalate, fast energy, and easy on the stomach before a start. Oatmeal the morning of and an apple at the finish round out a day that stays low on the oxalate scale while doing what race fuel needs to do.
Sports drinks and energy gels are the standard course fuel, and for a 5K most runners do not need them — plain water plus a banana covers the distance. When gels or drinks are used, the oxalate values are generally low, but the sugar and concentration matter for fluid balance, so the measured rule is: for a 5K, water is the fuel; the gel is only if you are a heavier sweater or the heat is extreme. Electrolyte drinks make sense after heavy sweating; energy gels at mile two of a 5K mostly add sugar without adding need.
Three habits cover most of the upside. Pre-hydrate the night before and the hour before the start — the start line is where races are won or lost for a stone plan. Take the banana as the pre-race fuel and water as the course fuel. And after the finish, keep drinking through the morning, because the race-day adrenaline masks thirst and the day's deficit settles in afterward. The medal is the fun part; the hydration is the part that carries into Monday.
See how oxalate values are measured and verified on our data methodology page.