You’re training for a half marathon and the question of nutrition keeps going round in your head. That’s completely normal — and actually a good sign. This guide focuses on the most underestimated phase of your preparation: the week leading up to the start, from D-7 through to your race-morning breakfast. Because arriving at the start line with fully loaded glycogen stores, a settled stomach, and a calm mind takes preparation well before the clock starts ticking.
For a complete overview of half-marathon nutrition — before, during, and after — check out our complete half-marathon nutrition guide. In this article, we go deeper on the preparation phase: the physiological mechanisms, specific foods, mistakes to avoid, and adjustments based on your profile.
Half Marathon: Do You Really Need to Carb Load?
The short answer: yes, but not in the same way as for a marathon. Let me explain why, with the physiology to back it up.
When running a half marathon at target pace — around 80–85 % of your VO₂max — your body runs primarily on muscle and liver glycogen. Your muscles and liver can store between 400 and 500 g of glycogen under normal conditions, equivalent to roughly 1,600–2,000 kcal of available energy. For the majority of runners who finish between 1h25 and 2h20, energy autonomy is therefore limited: after 60 minutes at that intensity, reserves start to drop off sharply. That’s why some runners hit the wall in the final two or three kilometres.
The good news: a well-executed carb load over 3 to 4 days allows you to achieve glycogen supercompensation — that is, to push your stores above their normal level. Reference work in sports nutrition — including literature reviewed by Nicolas Aubineau, sports dietitian and nutritionist — confirms that a high-carbohydrate diet in the days before an event increases glycogen stores and improves endurance performance. The principles apply to the marathon and the half marathon alike, with a protocol adapted to the distance. For a detailed breakdown across the full week, the marathon week meal plan covers the same mechanisms in depth — the logic is very similar; the volumes and duration of the loading phase differ slightly.
The key takeaway: carb loading for a half marathon should not start at D-7. You don’t need a full week of white rice and pasta — and you’d mostly end up feeling heavy and bloated at the start. The carbohydrate increase is gradual and targeted. Here’s how to structure it.
D-7 to D-4: Balanced, Light Eating
This first phase is often overlooked because it seems unremarkable. Yet this is where you lay the foundation for a successful week. The goal isn’t to dramatically increase carbohydrates yet, but to maintain a solid nutritional base while progressively reducing your training load (the classic taper).
What goes on your plate:
- Starchy foods at every meal: semi-wholegrain rice, al dente pasta, quinoa, sweet potato. A solid carbohydrate base, without excess.
- Lean proteins: chicken, turkey, white fish, eggs. They maintain muscle tissue without weighing down digestion.
- Cooked vegetables rather than raw: carrots, green beans, courgettes. Soluble fibre is easier to process; you’re starting to ease the digestive system.
- Good fats in small amounts: olive oil, rapeseed oil. No excess saturated fat.
- If you’re still training in the evening this week, plan a suitable pre-evening training snack so you don’t head out on empty and don’t compromise overnight recovery.
Hydration also comes into play from the very start: every gram of stored glycogen binds 3 g of water. Drinking well this week sets the stage for an effective carb load. Aim for at least 1.5 to 2 litres of water per day, without waiting until you feel thirsty.
What to avoid: large quantities of legumes (lentils, chickpeas), very spicy foods, heavy fatty dishes, alcohol. This is not the week to try a new restaurant.
D-3 to D-1: Progressively Increasing Carbohydrates
This is where the real carb load begins. Training is almost zero or very light; your body no longer needs as many total calories, but it needs more carbohydrates to saturate the muscles with glycogen. The goal: raise your carbohydrate intake to around 70 % of your daily caloric intake.
The key foods for these three days:
- White rice, white pasta, semolina, white bread: easy to digest, moderate glycaemic index, efficient absorption.
- Boiled or steamed potatoes (peeled): an excellent, highly digestible carbohydrate source.
- Ripe banana, unsweetened applesauce, clear fruit juice (no pulp): simple sugars that round out the meal.
- Honey or jam on toast: convenient ways to boost carbohydrates at breakfast and snack time.
- Protein in reduced portions: a serving of chicken breast, lean ham, or white fish is sufficient. Reduce, but don’t eliminate.
What you cut back significantly: fibre (no more raw vegetables, legumes, or wholegrain cereals), added fats (butter, sauces), aged cheeses. Your gut needs to be at rest on race day, not working through a fibre overload.
Running a spring or summer half marathon? Hydration becomes even more important, especially as temperatures rise. Check out our tips on hydration in hot weather to adapt your strategy.
Race Eve: The Smart Pasta Party for a Half Marathon
The pasta party is almost a tradition. But done badly, it can undo everything you’ve built during the week. Here’s how to get it right for a half marathon. For a deeper dive into this key meal, I’ve written a full article on the pre-race dinner for endurance events.
The golden rules:
- Eat early: ideally 12 hours before the start, which means 7–8 pm if you’re racing the next morning. Not 10 pm. The goal is to have everything digested when the alarm goes off.
- It’s a balanced meal, not the feast of the week: a generous plate of al dente white pasta (or white rice, semolina, according to your preference), a portion of light protein — chicken breast, steamed fish, lean ham — and a small serving of cooked vegetables.
- A drizzle of olive oil on the pasta, nothing more. No overly acidic jarred tomato sauce, no excess grated cheese, no cream.
- For dessert: unsweetened applesauce, rice pudding made with skimmed milk, or a very ripe banana. Simple and carbohydrate-rich.
- Zero alcohol. Even a single glass of rosé at dinner disrupts hydration, sleep quality, and muscle recovery.
One point many people get wrong: gorging on pasta the night before is NOT more effective than a sensible meal after three days of proper carb loading. Glycogen supercompensation is already well under way by D-3; the evening before, you’re finishing the job — not starting it.
Race Morning: The Ideal Breakfast
On race morning, your liver has been working overnight and its glycogen reserves have dropped. Your breakfast has one mission: replenish them without stressing your digestive system. There’s no need to get up at 5:30 am to eat a huge meal, nor to arrive at the start line on an empty stomach.
Timing:
3 hours before the start is the golden rule. This window allows complete digestion. If the start is very early and 3 hours before means getting up at 4 am, you can adjust: a light meal 2 hours before, plus a small digestible snack 30 to 45 minutes before the start (gel, very ripe banana, a few dates). Test this setup in training — never for the first time on race day.
What I recommend:
- White bread or white sandwich bread + jam or honey: the foundation. Little or no butter.
- Well-cooked oat porridge: sustained energy release, very digestible if you’re used to it.
- Ripe banana: potassium, simple carbohydrates, easy to carry if you need to eat on the go.
- Coffee or light tea if it’s part of your routine: caffeine slightly improves fat mobilisation and can sharpen focus. But don’t start using caffeine on race day if you’re not accustomed to it.
- Smooth applesauce, pulp-free fruit juice: to add carbohydrates without fibre.
What to absolutely avoid:
- Large amounts of dairy (unsettled stomach during the race)
- Pastries, croissants (fat + fast sugar = a poor pre-race combination)
- Muesli, seeded bread: too much fibre, too long to digest
- Anything you haven’t tried before. Rule number one: nothing new on race day.
Keep hydrating regularly up to the start, in small sips (150–200 ml every 20–30 minutes). Avoid drinking a large amount all at once just before the gun.
What to Absolutely Avoid in Race Week
Here are the classic mistakes I see most often that can undermine weeks of preparation:
- Starting the carb load at D-7: you’ll saturate too early, end up bloated and heavy. The truly high-carb phase begins at D-3.
- Testing new foods or products: no new gel, no new restaurant, no new pasta recipe. Everything you put in your mouth this week must be familiar.
- Neglecting hydration because you’re training less: this is a very common mistake. Tapering does not reduce your hydration needs — especially as glycogen stores are being built up.
- Having the pasta party too late or eating too much: dining at 10 pm the night before, or going back for seconds, won’t help you at all and will leave you with a heavy stomach at the start.
- Eliminating protein entirely: protein helps limit muscle catabolism. Reduce it, don’t remove it.
- Drinking alcohol: even in moderation, alcohol impairs glycogen storage, dehydrates you, and disrupts sleep quality. For the entire week — not just the night before.
- Changing your eating habits because you read something the night before the race: if it hasn’t been tested in training, it has no place in your race week.
Ograal Tailors All of This to Your Profile and Target Pace
The principles I’ve outlined here are scientifically sound and field-tested. But there’s a limit to any general-purpose article: it doesn’t know whether you weigh 55 kg or 85 kg, whether you’re targeting 1h35 or 2h10, or whether you have a sensitive stomach or an iron gut.
The exact amount of carbohydrates to target, the precise timing of your meals based on your start time, the foods to adjust for your digestive tolerance — all of that is what Ograal calculates for you. The app takes into account your weight, your target pace, your dietary habits, and your history to build a personalised plan, day by day, right through to race morning.
Want a personalised nutrition plan for your next half marathon? Try Ograal for free and arrive at 100% on the start line.
