California International Marathon Fueling Plan & Pace Chart

CIM Fueling Strategy

CIM is the rare marathon where the elevation profile helps your clock and hurts your legs at the same time. The course drops about 340 feet net from Folsom Dam to the Capitol, but it does it across 663 feet of climbing and 1,003 feet of descending. Every foot of that descent is an eccentric contraction through your quads. By mile 20 your legs are more damaged than your split times suggest, and damaged muscle is worse at pulling glucose out of your bloodstream. That is the whole fueling argument for this race. Fuel like a hard marathon even though it feels like an easy one.

Take your first gel by mile 3. The first six and a half miles drop about 170 feet and you will be running well under goal pace without trying. Cold air, a downhill grade, and taper legs make mile 3 feel like a warm-up, which is exactly why runners forget to start fueling. Start the clock early and hold 75 to 90 grams of carbohydrate per hour from that first gel forward. At 3:30 pace that is roughly a gel every 20 to 22 minutes if you are running gels alone, or a gel every 25 minutes plus consistent cups of the on-course drink mix.

Miles 6.5 to 9 are the only net uphill on the course, about 45 feet of gain including a 31-foot climb at 7.5. This is the section most course guides call the toughest on the course, and it is also where the first gel station sits at mile 6.4. Take a gel there or just before. Your effort is about to rise while the grade turns against you, and you want carbs already moving through your gut before that happens rather than swallowing something mid-climb.

Miles 10 through 12 are the part of CIM that quietly decides your race. Inside a single mile you get the steepest descent on the course at mile 10.2, a 30-foot climb at 10.5, a 60-foot drop from 10.75 to 11.06, and then the steepest climb on the course at 11.2. That sequence is short but it is the highest-force quarter of the day. Do not fuel during it. Take your gel at mile 10, before the drop into Old Fair Oaks Village, and then leave your gut alone until the road settles down after mile 12.

The mile 13.6 gel station is your most important checkpoint. If you are on plan you should have taken four to five gels by halfway. If you are behind, this is the last comfortable place to catch up, because from mile 15 onward the terrain gets easier and your pace will climb, which raises your carb oxidation rate at exactly the moment your damaged quads are getting less efficient. Runners who arrive at mile 20 having taken four total gels are the ones walking on L Street.

Miles 15 to 20 flatten out along Fair Oaks Boulevard and drop about 90 feet with very little roll. This is a false sense of security. The road is straight, the crowds thin, and the effort feels like a long tempo. Keep the timer running. Gels at 16 and 19 or 20. If you are using the course drink mix (Precision Fuel & Hydration, 60g carbs and 1,000mg sodium per liter), a 5 oz cup delivers roughly 9 grams of carbs and 150mg of sodium, so two cups is meaningful but not a gel substitute. Plan cups as a supplement to your gels, not in place of them.

The last six miles are nearly flat, and the mile 21.4 gel station is the last one on course. Take one even if you feel fine. A gel at 21.4 lands in your bloodstream around mile 23, which is precisely where quad damage from the first thirteen miles turns into a pace cliff. The bridge over the American River around mile 22 is a 20-foot up and over, and it is the only grade change left. Fuel before it, not on it.

Cold changes the math in your favor and against it. A 41 to 43 degree start with gut absorption near its best is ideal for aggressive fueling, and CIM's 28-year average is a 42 degree low and a 55 degree high, so this is usually a fast, cool day. But cold hands cannot open gel packets. Pre-tear your gels the night before, or run gloves you can pull off. Thirst also disappears in cold air, so drink on a schedule rather than on feel. Rain has fallen in 7 of the last 28 years, and valley fog in the early miles is common. In wet conditions your soft flask and gel wrappers get slippery, and hypothermia risk rises in the final miles when your pace drops, so carry one more gel than you plan to use and treat the mile 21.4 station as a backup rather than your primary plan.