Eating before a marathon: meals and carbohydrate loading

In the week leading up to a marathon, combine familiar meals with a higher carbohydrate intake over the final few days. The aim is to fill glycogen stores, the form in which the body stores carbohydrates, without causing digestive discomfort or relying on exceptionally large meals.

Rice, pasta, bread, potatoes and fruit are useful choices, accompanied by protein and vegetables each runner tolerates well. The approach also includes regular hydration, reduced training volume and a familiar breakfast on race day. Amounts depend on body weight, preparation, tolerance and race conditions.

Why carbohydrates matter over 26.2 miles

During a long run, the body gets energy from both fats and carbohydrates. The latter are stored mainly as glycogen in the muscles and liver. Those stores are limited, and how quickly they are used depends on factors including pace, duration and a runner’s preparation.

A carbohydrate-rich diet combined with reduced training in the days beforehand can increase the glycogen available at the start. This does not guarantee a fatigue-free race or remove the need to fuel during it, but it helps runners begin the effort with better initial reserves.

The taper means reducing the training load so that a runner reaches race day better rested. There is no need for an exhausting workout or several low-carbohydrate days before increasing intake: those older protocols can add fatigue and make the week unnecessarily complicated.

Seven to four days before: eat a balanced diet

During the first half of the week, a sensible approach is to stick with familiar meals and avoid restrictions. Cutting mileage does not require cutting out rice, pasta or bread: muscles still need energy, and recovery from earlier training is ongoing.

Oats with yoghurt and fruit for breakfast, rice with chicken and vegetables for lunch, and potatoes with fish for dinner are possible examples. Eggs, tofu, pulses and other protein sources also fit, according to individual habits and tolerance.

Fruit, vegetables, whole grains and familiar fats such as olive oil still have a place. There is no reason to remove fibre for a whole week if it causes no problems. At this stage, eating enough and choosing a varied diet matter more than chasing an exact percentage of nutrients.

If appetite falls as training decreases, avoid letting meals become too small. A simple snack, such as yoghurt with fruit or a small sandwich, can round out the day. Race-week nutrition is not a weight-loss diet immediately before competition.

The final two or three days: carbohydrate loading

For prolonged endurance events, sports nutrition guidance commonly puts carbohydrate loading at around 8 to 12 grams of carbohydrate per kilogram of body weight per day during the final 36 to 48 hours, alongside reduced training. Some people spread the increase over two or three days to make it easier to tolerate.

For a runner weighing 70 kilograms, that range means 560 to 840 grams of carbohydrate per day, not that weight of pasta or rice. It is a substantial amount and not a requirement for everyone: the upper end can be difficult to reach. Experience, body size, health and digestive tolerance all affect the choice.

The number on a food label refers to the nutrient itself. As a guide, 100 grams of dry pasta provides around 75 grams of carbohydrate, while 100 grams of white bread generally provides around 50. Values vary between products, and cooked pasta weighs more because it absorbs water: dry weight should not be confused with the weight served.

Spreading carbohydrate sources across breakfast, lunch, dinner and an occasional snack is often more comfortable than concentrating them in one meal. Bread with jam, rice, pasta, fruit purée or a carbohydrate drink can be combined according to preference. Supplements are not essential, and foods do not have to be selected by glycaemic index.

Small portions of protein and fat can remain part of meals during this phase, without crowding out carbohydrates or making the meal overly heavy. Glycogen is stored with water, so body weight may rise temporarily. That change alone does not indicate an increase in body fat and is not a reason to stop drinking.

A sample menu for race week

To illustrate the progression, this example assumes a Sunday race. Meals are interchangeable and portions should be adjusted to the individual; the menu does not guarantee a specific carbohydrate intake unless portions are calculated. It also does not replace an individual plan when there is a clinical need.

From Monday to Wednesday, breakfast might combine bread or oats with fruit and yoghurt. Lunch could be rice with fish and cooked vegetables; dinner might be potatoes with an omelette and a salad if tolerated. Fruit, a sandwich or a familiar dairy product can fill the gaps between meals, without needing to eat all of them.

Thursday can follow a similar pattern while giving more space to rice, pasta or bread. For example, toast with jam in the morning, pasta with chicken and courgette at lunch, and rice with egg in the evening. Fruit purée or a banana can round out the day.

On Friday and Saturday, carbohydrates take a more prominent role: white bread with jam and fruit for breakfast; rice with fish or tofu and cooked carrots for lunch; pasta with a mild sauce and a moderate portion of protein for dinner. Snacks help spread the volume of food if the daily target is high.

These dishes are examples, not a compulsory sequence. Vegetarians can replace fish or meat with eggs, dairy or tofu they tolerate. For coeliac disease, rice, potatoes and certified gluten-free bread or pasta are alternatives; ingredients in sauces and prepared products also need checking.

Fibre, fat and foods that may cause discomfort

Fibre benefits health and does not need to be eliminated as a rule. However, reducing it during the final 24 to 48 hours may help runners who usually experience bowel urgency or bloating while running. Temporarily switching from wholemeal to white bread or choosing cooked vegetables are simple adjustments.

Tolerance varies. One person may eat yoghurt for breakfast or have a banana without trouble, while another may need a different choice. There is no general ban on dairy, fresh fruit or pulses either: what matters is the amount eaten and each runner’s response, especially close to the start.

Very fatty, large or spicy meals can be uncomfortable for some people. The risk may rise when they coincide with nerves, travel or an unfamiliar dinner time. A familiar, moderate meal is generally more predictable than a new recipe, even if the latter is marketed as particularly suitable for sport.

Alcohol can disrupt sleep and offers no advantage in race preparation. Magnesium or other mineral supplements are not a guarantee against cramps, which have varied causes. Taking them unnecessarily may cause discomfort or interfere with treatment; deficiencies should be assessed individually.

Dinner the night before and race-day breakfast

The previous evening’s meal completes the work of the preceding days, but it does not need to become a pasta binge. White rice with an omelette and cooked carrots, or pasta with a mild tomato sauce and fish, are possible options. Leaving time to digest before bed can help, without imposing a universal dinner time.

If Saturday lunch was substantial, a more moderate dinner may feel comfortable. A carbohydrate-rich afternoon snack can also help distribute intake. The priority is not to finish with an overfull stomach, but to reach bedtime without intense hunger or heaviness.

Breakfast helps replace some of the liver glycogen used overnight. A general reference for a pre-exercise meal is 1 to 4 grams of carbohydrate per kilogram of body weight one to four hours beforehand, although not everyone tolerates the higher amounts. The start time and each runner’s experience guide the choice.

For a 9 a.m. start, breakfast around 6 or 7 a.m. gives many people time to digest. Bread with jam and a banana, or white rice with a small portion of protein, are alternatives. The amount should resemble what has been tested on long training runs; there is no need to include every food at once.

A familiar coffee is an option for those who tolerate it, but increasing caffeine or trying a gel on an empty stomach for the first time can cause problems. A small carbohydrate intake close to the start is optional and depends on the strategy already practised. No single food guarantees protection against a late-race slump.

Hydration: arrive with enough fluid, not too much

Drinking regularly throughout the week and having water with meals is usually sufficient under normal conditions. Needs change with heat, body size, sweat and the foods consumed. Thirst and pale yellow urine are useful practical references, although they are not perfect measures.

A pre-exercise reference is approximately 5 to 7 millilitres of fluid per kilogram of body weight about four hours beforehand: for 70 kilograms, roughly 350 to 490 millilitres. It is not an amount to force on top of adequate drinking and may need individual adjustment.

Drinking large volumes out of fear of dehydration can be harmful. Excess water, especially during prolonged exercise, increases the risk of hyponatraemia, a fall in blood sodium concentration. Nausea, headache, confusion or worsening symptoms during or after a race require medical attention; they should not automatically be treated by drinking more water.

The salt in normal meals is usually sufficient before the start, and not everyone needs electrolyte tablets. During the race, needs change with duration and sweat loss. On warm or humid days, such as those possible on the Mediterranean coast, expectations may need adjusting without treating the heat as a reason to drink without limit.

Fuel during the race matters too

Starting with full stores does not replace fuelling over 42.195 kilometres. For many runners, a reference is 30 to 60 grams of carbohydrate per hour, depending on duration and what they have practised. During prolonged efforts, higher amounts of up to 90 grams per hour can be used when the digestive system has been trained to tolerate them.

Gels, sports drinks and other foods provide different amounts. For example, two gels containing 25 grams each add up to 50 grams, but carbohydrates in a drink also count towards the total. Timing should account for aid stations, expected pace and tolerance, rather than relying only on a fixed distance between servings.

Fluid needs during a race depend on thirst, heat, speed and sweat rate. No single hourly volume suits everyone, and drinking more than is lost over several hours can be dangerous. Sodium in a drink does not by itself eliminate the risk of hyponatraemia if too much fluid is consumed.

After the finish, a meal or snack containing carbohydrates and protein, along with fluids and some sodium where appropriate, helps start recovery. If the stomach is unsettled, intake can be gradual. There is no need to force a large meal or a fixed quantity of water immediately after finishing.

A strategy shaped by each runner’s experience

These figures are general references, not identical instructions for everyone. Someone with diabetes, kidney disease, a history of eating disorders, frequent digestive symptoms or medication affecting fluid balance needs to discuss changes with a healthcare professional before putting them into practice.

Preparation benefits from testing breakfast, foods and hydration on long training runs. That experience helps distinguish a useful recommendation from an approach that does not sit well. In the final week, the strongest combination is also the least dramatic: familiar food, rest and adjustments proportionate to the effort ahead.