The marathon is not lost at 35 km. It is lost in the small decisions made in the 72 hours before and, above all, in the management of carbohydrates + fluids + sodium from the start. Your body doesn't "run out of legs" suddenly — it charges you interest for every minute of energy deficit or every hydration error.
Below is a complete guide, based on the plan you shared, designed to serve as a roadmap for participants of the Porto Marathon 2025.
1) The real goal of a nutritional plan
Before "what to take," it's important to align "why":
Maintain stable energy availability (CHO) to delay central and peripheral fatigue.
Protect the stomach (the #1 limiter in a marathon, more than the legs).
Avoid significant dehydration, without falling into the opposite error (drinking too much).
Use caffeine as a tool, not a blind gamble.
"Common (and dangerous) assumption: 'If I'm well-trained, nutrition is a detail.'
In a marathon, nutrition is part of training. If you haven't tested it in long runs, you're improvising on the most expensive day of the year."
2) Strategy 2–3 days before: preparing the body for absorption
The basic plan recommends:
Hydration (72h pre-race)
Increase fluid intake in the 3 days prior.
Practical reference: ~1L water + ~1L isotonic per day (adjust to your size, sweat, and temperature).
Carb-load (without exaggeration)
+10% slow-absorbing carbohydrates: rice, pasta, potatoes, sweet potatoes, mixed bread.
Simple protein: fish, white meats, eggs or tofu, simply prepared.
What to cut (to reduce GI risk)
No alcohol.
Avoid sweets, spicy foods, and "unfamiliar food."
The day before: low fiber and fats (legumes, seeds, nuts, very "heavy" dishes).
Moderate fruit and dairy (not "forbidden," but risk management).
Example pre-race dinner
Rice or pasta + grilled chicken + few vegetables + 1 fruit (early).
Simple, repeatable, digestible.
3) Race morning: hydration and timing
The plan indicates a useful rule for 2 hours before:
- 5 to 10 ml of water per kg of body weight (adjust to climate). Ex.: 60 kg → 300 to 600 ml in the 2 hours before, without "drowning" the stomach.
Breakfast:
- Repeat what you do in long training runs. Don't invent.
Warm-up:
- Light and controlled.
Important note about the "10 minutes before" gel
Your text suggests: "10 minutes before the run – one gel".
This can be excellent (starting with available CHO), but only if:
- you've already tested it in training, and
- it doesn't give you a peak/crash or discomfort.
If you're sensitive, you can swap it for half a gel or take it 15–20 min earlier.
4) In-race plan: the roadmap (km + approximate time)
The logic of this plan is good: start conservatively, activate early, stabilize, reinforce before the wall, and use caffeine strategically.
Intake guide (during the 42 km)
Km 0–5
Water only
Objective: allow the body to stabilize, without overloading the stomach right at the start.
Km 4.5 (~0:25 h)
HC21 — 22 g CHO | 90 mg caffeine
Accompaniment: small sips of water
Objective: activate initial energy supply.
Km 9.5 (~1:05 h)
HC41 Endurance — 41 g CHO | 0 mg caffeine
Accompaniment: ~200 ml water
Objective: stabilize carbohydrate intake.
Km 15 (~1:40 h)
HC41 CAF Endurance — 41 g CHO | 150 mg caffeine
Accompaniment: ~200 ml isotonic + ~100 ml water
Objective: enter the prolonged endurance phase.
Km 24 (~2:15 h)
HC41 Endurance — 41 g CHO | 0 mg caffeine
Accompaniment: ~200 ml water
Objective: sustain before the "wall."
Km 30 (~2:50 h)
HC21 CAF ISO — 22 g CHO | 90 mg caffeine
Accompaniment: ~200 ml isotonic
Objective: quick energy + mental focus.
Km 35 (~3:20 h)
HC41 CAF Endurance — 41 g CHO | 150 mg caffeine
Accompaniment: ~200 ml water
Objective: reduce feelings of fatigue.
Km 39–40 (~3:45 h)
SOS 1 HC21 ISO (without CAF) — 11 g CHO | 0 mg caffeine
Accompaniment: sips of water
Objective: final "push" to the finish line (if you can still tolerate it well).
Total plan (if you do everything):
- 219 g of carbohydrates during the race
- 480 mg of caffeine
These indications are a guide to help refine your strategy; they should be adjusted according to your habits.
You should take gels and refuel before you feel the need, thus avoiding hitting a wall.
The gel can be eaten in portions; you don't need to eat it all at once.
At water stations (grab the water bottle, you don't need to drink it all, but you can use it to wet your back, neck, head, to reduce losses)
