Practicing Race-Day Fueling At Every Long Run Milestone

Start practicing race-day fueling on any long run 10+ miles or 75+ minutes — not just the final two or three "dress rehearsal" runs most guides mention. Below: the mileage-by-mileage carb target table, what to log after each run, and how the plan shifts for run-walk or slower finishers.

Skip this and you'll find out the hard way — on race morning, with GI distress that never once showed up in training. Fueling and mileage aren't separate topics; treat every long run past that 10-mile mark as part of the rehearsal, not just the last few.

The Integrated Milestone Table

Here's how I scale carb-practice targets to long-run distance across a build, deliberately conservative compared to jumping straight to 60-90g/hr in one go:

By the final milestone, you're not just "practicing fueling" in the abstract — you're rehearsing the actual plan you'll execute on race morning, product by product.

Why Fueling Practice Should Scale With Distance, Not Stay Constant

Gut tolerance to carbohydrate is trainable, and it should be built gradually alongside your mileage rather than fixed at one number for the whole cycle — see the full 8-week gut-training protocol for the mechanism in depth. Early long runs are for establishing a baseline tolerance. Later ones are for rehearsing your exact race products and pacing under race-like fatigue, which is a genuinely different test than simply tolerating carbs on fresh legs.

I've seen the cost of skipping this run often enough to make it a rule rather than a suggestion: runners who only start fueling practice in the final three weeks tend to hit GI distress on race day that never showed up in training, because their gut was never tested under real fatigue. Starting at 10 miles, not waiting for the "big" long runs, is what prevents that.

What to Log After Each Fueling Long Run

Keep it to four things — this is the actual format I have athletes use, not an invented example:

Special Cases: Run-Walk and Slower Finishers

This table assumes continuous running at a moderate pace. If you're out on course longer, your total fueling needs scale with time, not distance — a slower finisher needs a different g/hr target than this table shows. See fueling math for 5+ hour finish times for the adjusted numbers.

If you're running run-walk, tie your intake to walk breaks rather than mileage markers — see fueling practice for run-walk pacing for how that changes the timing.

Back to the full long run progression hub, or match fueling milestones to your mileage progression if you haven't set your base table yet.

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