I've trained my body over the years to go from 100 to 160 grams an hour, and this is where I perform the best.

Most runners race on 40 to 60 grams of carbs an hour because that is what the gel packet math hands them. Two gels an hour, maybe three. Then the last quarter of the race arrives and the engine goes quiet, and they call it a bad day. It was not a bad day. It was an empty tank.

The gut is trainable like everything else. I did not start at 160 grams an hour. I started near 100 and added a little at a time over years, teaching my stomach to move sugar while my legs were working. That is the part every high-carb headline skips. The number is earned, not swallowed.

The research backs the direction. In the Viribay study, elite runners taking 120 grams an hour through a mountain marathon showed less muscle damage and lower internal load a day later than runners at 60 or 90. Read the fine print, though. Those athletes gut trained first.

My race protocol is 140 to 170 grams an hour, all of it maple syrup. A 5 ounce flask holds roughly 160 grams of carbs, which means an hour of fuel rides in something that costs less than two dollars and never wrappers out of my pocket at mile 60.

If you want the number to move, move it slowly. Add about 10 grams an hour to your long-run fueling every few weeks. When your stomach protests, hold there, then try again a month later. The ceiling is higher than you think, but the staircase is long.