Road running race-day fuel plan
In road running, repeated impact stresses the digestive system. Most marathon DNFs come from GI symptoms or hitting the wall, both preventable with planning.
Carbs by distance
10K (40-60 min): 0-30 g/h, optional pre-race gel. Half marathon (1h20-2h30): 30-60 g/h, usually 2-3 gels. Marathon (3-5h): 60-75 g/h, gels every 30-40 min with 2:1 blend. Road ultra (50K-100K+): 60-90 g/h, with a light meal at 4-5h.
Pre-race in running
Carb loading 1-2 days before at 8-10 g/kg/day (white pasta, rice, potato, bread). Breakfast 3h before with 1-2 g/kg of carbs, avoiding fibre and fat. Pre-start snack (15-20 min before): gel + 150 ml water. For afternoon races, a pre-race lunch at T-3h with simple pasta + lean chicken or fish.
Where to take the gels
In a marathon, the critical points are km 12-15 (first decisive gel), km 21-25 (second gel), km 30 (gel + caffeine), km 35 (last gel if the stomach holds). Always take water with the gel (prevents slow emptying from high osmolarity). In official races, know where the water stations are before the start and mentally map when to take each gel relative to them.
Carb loading without gaining weight: the 3-day method
Myth: carb load means stuffing pasta = extra weight to run. Correct method: 3 days at 8-10 g/kg/day substituting macros, not adding. Cut fat below 20% of total calories (lean fish instead of salmon, chicken breast instead of thigh, avoid abundant olive oil). Each gram of glycogen stores 3 g of water, so you will gain 1-2 kg of weight, but it is metabolic water that leaves through sweat during the race and acts as available energy. Do not eat extra dessert: substitute the fat/protein component of the plate with more simple carbs.
Gel table for a sub-4 marathon
T-15min: 1 gel + 200 ml water. Km 8: 1 gel + 100 ml water. Km 16: 1 gel + 100 ml water. Km 23: 1 caffeine gel (50-75 mg) + 100 ml water. Km 30: 1 caffeine gel (100 mg) + 200 ml electrolyte water. Km 36: 1 fast gel (fructose-dominant 80%) if stomach allows. Total: 6 gels at 30 g = 180 g of carbs over 4 hours = effective 45 g/h (60 g/h including carb drink). For sub-3:30, step up to 70-80 g/h alternating gel and drink sips at each aid station, add 1 extra gel at km 5 and km 12.