Ultra Trail du Mont-Blanc and Sports Nutrition

Text | Dietician Nutritionist Corinne Peirano,  diet.peirano[at]

The dietary advice from these pages is designed to optimize firstly athletic performance in the four races and secondly, to facilitate recovery. They are the general principles of sports nutrition adapted from situation to situation; metabolism during exercise is highly variable between one runner and another, and one race to another (time, distance, altitude, intensity).

Three essential phases to remember: 


Saturate muscle glycogen stocks

> Day-7: diet with normal proteins, low fat, slightly high carbohydrates. Ration of 2 400 to 3 500 kcal by athlete with Proteins = 15 %; Fat = 20-25 %; Carbohydrates = 60 % + Hydration.
Final week: we must anticipate the future energy needs of the race and maintain our metabolism in top form. That is to say, structure the supply in three to four daily meals, without excess, without snacking during the day. Hydration: 1.5 to 2 L / day.
Breakfast will change during this week: include an additional protein with a slice of ham or boiled egg or white cheese (0 or 20 % fat) or soya yogurt.

> Day-3: carbohydrate diet for the endurance athlete (Carbohydrates = 65-70%), complex carbohydrates at every meal (cereals with bread).
The nutritional goal is to increase and even double the muscle glycogen, with two large plates of carbohydrates per day, bread at every meal (cereal in the morning according habit). Some foods can be omitted for the comfort of the digestive system: spicy foods, fatty meats, cooked fats, milk, cheese rich in fat, including hard cheeses (Parmesan, Cheddar), some vegetables with hard fibres such as salsify, peppers, onions, garlic, artichokes, cabbage... Choose low to medium GI cereal: spaghetti, macaroni, basmati rice or quinoa.  Potatoes with firm flesh are also possible. Cook by steaming, or cook the food in broth, in a bain-marie, in the oven, or cook in foil ... Eat non-irritant cooked fibrous vegetables such as : leeks, asparagus tips, carrots, beets, endive, courgettes (seeded), salad leaves excluding the centre, green beans, and lean meat or fish, fruit like apples or slightly ripe bananas, stewed fruit, yoghurt semi-skimmed or 0% or soya yogurt, desserts such as rice or semolina milk or soya or rice milk, or almond or chestnut milk if "milk" in this form is more acceptable.

> Day-1 : Basics
- Don’t skip meals
- Each meal should consist of cereal products and easily digestible foods
- Regular hydration throughout the day with a low-mineralized water
- Don’t gorge at the pasta party: too many complex and simple carbohydrates during this meal may interfere with your digestion, create gastric reflux, promote intestinal fermentation during the night and can sabotage the last night of sleep.

> Race Day : breakfast high proteins and high carbohydrate
Example: 100 g to 200 g of cheese 20% or 0% fat + toast or whole-grain bread and a little butter or porridge flakes, buckwheat, oats or muesli, or rice cake + jam, agave syrup or chestnut puree + 1 slice of defatted ham or 1 egg (scrambled, omelette or boiled) + 1 fruit puree + breakfast drink: coffee or tea (according to habits) or energy cake if you want.

> Race Day : meals pre-competition
Basically, the profile of this meal is the same as breakfast. Firstly an easily digestible meal to facilitate gastric emptiness. It will consist of complex carbohydrates (cereals, bread), low fat protein, uncooked fat, a little salt, a few of simple carbohydrates and water for hydration.
Specifically, this meal can be divided into 4 to 5 components according to appetite: cooked vegetables as a starter, cereals (basmati rice, spaghetti, quinoa ...) with meat or fish, white cheese or unfermented cheese and sweet dessert: fruit pie, rice or semolina cake, or a stewed fruit and gingerbread. Drink water moderately according to gastric tolerance. No alcohol.

If it’s a restaurant option, it is advisable to check the menu while avoiding the pitfalls of a menu too rich in fat or based on a dish of meat sauce. If a restaurant is chosen, it is advisable to check the menu to avoid the pitfalls of a menu too rich (too fat) or menu based on a dish of meat with sauces. That could stimulate digestive system excessively before the event (heavy digestion, digestion time increased, risk of nausea or disgust), the organs within the abdomen are also subject to a pre-competitive stress.

If for any reason the formula is a sandwich, it is best to make it yourself at home for better hygiene and for the rule of common sense "at least, we know what is inside." The classic ham (2 slices) and butter should be complemented by stewed fruit, rice or semolina cake, or an apple (the easiest fruit to digest) and 2 to 3 slices of gingerbread if hunger persists. Drink: water or fruit juice.

> Race Day: 2 hours 30 minutes before departure and every 30 minutes
Moderate caloric intake (if hungry) will maintain blood glucose levels and protect glycogen: 20 to 30 g in a single intake cereal bars or biscuits (fat <10 g for 100 g) + water. The hydration (water) should be regular and moderate.

> Race Day: 30 to 15 minutes of departure
Catecholamine and stress hormones (adrenaline, Cortisol) can induce a slight hyperglycaemia. To prevent the decline of glycogen, it’s possible to prepare a drink, with mainly fructose and by measuring the drink carefully: 20 to 30 g maximum fructose / L, fructose may be a cause of diarrhoea in a sensitive ultra runner. Grape juice diluted with water (1 volume of grape juice for 1 to 2 volumes of water as tolerated) can also be agreeable: to be tested beforehand in training or during a minor race. In the case of digestive disorders, hydrate regularly with small amounts of water and do not eat. Remain calm, because all will be well, of course everything will be alright!

II – The race

Two goals: 1/ Promote athletic performance
                 2/ Prevent or limit digestive problems

> Promotion of athletic performance needs energy (calories) during the race

> Nutritional objectives of the race :

  • Manage the depletion of muscle glycogen and the liver (official supplies and regular spontaneous food intake)
  • Protect the muscle fibres (Food and Hydration)
  • Mobilize fat (intensity sub-maximal effort – aerobic spinneret)

No innovations during the race but many rehearsals beforehand, to complete the nutritional preparation

Food during the race could be composed mainly of half-fast carbohydrates (liquid or half-liquid), but for the time and distance required by this class of runners, energy intake of slow carbohydrates (bread, cereal bars, dry cookies and so on) homemade and official supplies. Provide small meals every 2 to 3 hours depending upon digestive capacity.

> Think of a combination of salty and sweet
with carbohydrate intake ranging from 15-20 g / hour for the fragile digestive systems, up to 50 g / hour for big eaters (gels or sports drinks with carbohydrate intake for Effort, cereal bars, and salty foods such cashew nuts or macadamia, crackers, stewed fruit, gourd, chestnut cream ...) and enjoy supplies to restore both in salty and sweet, (soup and pasta if supported, bread, cheese, cake, gingerbread, dried meat, ham, cereal bars, chocolate etc..).

> Protecting the digestive system to prevent or limit the indigestion:
. You must chew! If the size of food particles is greater than 2 mm, there may be partial or total inhibition of gastric emptying. In other words, think of chewing to facilitate the absorption of food. Concerning the quantities: portion size should be tested during training. It is strongly recommended that you test and train your digestive capacity for the long efforts, running longer races with a full stomach, or by reducing energy intake (but beware of hypoglycaemia) to very small quantities.

Hydration. one of the major causes of digestive disorders!
Dehydration and a deep body temperature increase due to the effort will slow gastric emptying, also stress, the volume of liquid absorbed, the intensity of the race, the steepness of the slope, whether it is a very steep descent or not all play their role. One of reasons: portal blood flow (region of the liver blood) is reduced by 50% to 80% according to individual runners. Drink isotonic sports drinks containing carbohydrates and electrolytes, if this type of drink is well tolerated (test beforehand in a long-term training).

Consider factors affecting gastric emptying. Paying attention to the both: volume / flux of liquids and solids ingested.  Measure the drink out well: a too higher concentration (excess energy) may prevent gastric emptying. Check before buying the amorality and pH of the energy drink which is normally shown on the packaging, if necessary; ask the manufacturer for these settings. The effective Osmolality of an energy drink is approximately 290 mOsmol. The hypertonic drinks (Osmolality > 290mosmol) can increase dehydration and cause transfer of water from the cells to the middle of the intestines (risk of osmotic diarrhoea).
Schedule recovery breaks after long and hard downhill stretches because the shocks can severely affect the digestive system. Do not wait to be dehydrated, to drink, but conversely, do not drink in excess to counteract  dehydration. On average, you should drink 1-2 sips every 15 minutes (Hydration adapted to each case).

> Hydration Strategy, Why?

  • to limit the increased sense of exhaustion (due to the rise of body temperature)
  • to limit dehydration (protection of the digestive system, maintain plasma volume ...)
  • to limit the loss of minerals through sweat (by regular liquid intake without excess)

Measuring out the energy powder: 30 to 80g per litre, to be adapted according to the temperature (with electrolytes in the drink with sodium). In any case, do not overdose: do not exceed 120g carbohydrate / litre. Reminder for the right mix of the beverage: the hotter it gets, the less energetic powder you put in your drink. The colder it gets, the more energetic powder your beverage should contain. Another reminder, water for hydration is insufficient (risk of hyponatremia). Provide salt intake (one dose of salt is 1.2 to 1.5 g / L = 400 mg sodium) and sugar if the drink is made by the runner (e.g.: tea with lemon juice with sugar AND salt) during refuelling. Alternative carbohydrates: a piece of white sugar equals 5 g carbohydrate rapid assimilation. Note: the salt facilitates the absorption of carbohydrates.

III - Recovery.

2 goals: 1 / countering the effects of dehydration
             2 / fill the glycogen stores emptied by the effort

To facilitate recovery, glycogen stores have to be reinitiated very quickly. You have to take advantage of the presence a metabolic window after the run to do it, because you have a relatively short space of time (countdown) immediately upon your arrival, for the restoration of depleted stocks. Your body is particularly sensitive to this notion of time, especially because the new synthesis of the glycogen also consumes energy.
After the competition, it is necessary to:

  • Hydrate yourself to restore the water reserves of the body and remove metabolic waste
  • Fill, as fast as possible, glycogen stores emptied by the duration and intensity of the race,
  • Soothe the inflammation of the muscles consecutive to efforts eccentric of the running race
  • Fight against free radicals produced during the race, by an increased intake of antioxidants
  • Hydrate yourself and eat consciously to eradicate tissue acidity
  • Soothe the digestive system weakened by the effort

> You have about 30 minutes after the arrival of the race to meet immediate needs.
· Ideally, at the beginning, you have to hydrate yourself with a recovery effort drink of (with carbohydrates)-enriched amino acids Branched (BCAA) alternately with mineral water-enriched in bicarbonates (for an anti-acid effect).
· Or you can eat solids: some banana, energy bar, or gingerbread  ... and drink mineral water with bicarbonates, low in sulphates and nitrates (or Arvie or Quezac in France), taking into account the state of your digestive system on arrival.

> Within 4-6 hours until the main meal, regularly provide about 50 grams of carbohydrate per Hour.
· Either with a recovery energy drink, drinking it very regularly or alternately with a mineral water-enriched with bicarbonates,
· Or with solids (don't forget to drink mineral water enriched with bicarbonates): fruit like an apple or a pear or ripe banana or apple puree to soothe the digestive system, dried fruit (apricots or prunes ...) and nuts (almonds or hazelnuts ...), soya yoghurt and cake or cookies that can be also some dietetic energy biscuits...

> At the main meal after the race, you have to eat according to your hunger but without excess:

  • Fish, soya burger or white meat, cooked vegetables, as for example soups and / or support (e.g. vegetable flan) starches, which are preferably potatoes with firm flesh (steamed or boiled) for their alkalizing property, pasta or rice are also good.
  • Use colza oil or nuts for your seasonings (omega3 intake)
  • Cooked fruits and oilseeds (almonds, hazelnuts ...) during or after food
  • 1 yoghurt (sheep, goat, cow, soya) with any sugar
  • Continue to hydrate yourself with bicarbonate water and / or your energy drink.

This ration, after the race, provides the minerals and trace elements that will facilitate the recovery such as potassium, magnesium, alkaline foods and essential fatty acids.

On arrival, retain the general rule: eat quickly and hydrate well. Do not abuse Coke (acidifying drink) or beer (diuretic), avoid dark beer (toxins), but a beer with friends upon arrival to celebrate this passage under the banner is not ruled out!

IV. Control of body weight - Fighting being overweight

Body weight should, normally, be controlled throughout the year, and not the day before the race. The adipose tissue is, indeed, a place which stores body fat, which fills up very easily, but do not forget is also a good source of energy (recall: 1 g fat = 9 kcal). Overweight is in all cases, a situation that packs the processes of lipogenesis and lipolysis of the body. When these two physiological mechanisms are unbalanced they will no longer play their role in regulating the storage of body fat.
If you need to lose weight, in addition to the usually recommended balanced diet, here are some simple rules with 10 principal pointers which can help you in everyday life (there is an overall scientific consensus on their effectiveness):

> 10 Tips for easy weight loss

  1. Reduce consumption by 500 calories per day, limiting food or fancy snacks, alcohol, eat balanced diet, and effortlessly lose about 2 kg per month.
  2. Avoid food cravings by promoting foods rich in precursors of serotonin: eggs, milk semi-skimmed milk (1 to 1.5% fats), avocado, eggplant, banana (small = 80 g), dates, nuts, plum tomatoes ...
  3. Keep food to medium and low glycemic index: unrefined cereals and bread.
  4. Eat at least 20 grams of fibre daily: 3 servings of vegetables (raw and cooked) and 2-3 fruits per day, unrefined bread (whole wheat bread) or sourdough bread (pure) or cereal.
  5. Increase daily intake of magnesium: seafood, shellfish, vegetables, whole grains, nuts, mineral water ... 
  6. Increase daily intake of omega 3. Rapeseed oil (organic) for seasoning (or soya or nuts): 2 tbsp per day. Eat fatty fish (mackerel, salmon, sardines, herring, mullet) at least twice a week...
  7. Increase Metabolism Base (MB). Training by increasing the rate of lean mass will inevitably increase the MB (particularly if you have the habit of running ultra trails).
  8. Eat slowly to allow time for the brain to transmit the signals of satiety to the gut and prevent you from swallowing a surplus of calories. Finally, reduce portions on the plate, don’t accept King-size portions.
  9. Focus on good fats. Targeting quality with unsaturated fats: omega 3 (rapeseed oil or nuts, or soya, fatty fish) and omega6 (for these fatty acids, no worries, they are often found in foods). 2 tbsp rapeseed oil per day (for seasoning) 1 tsp olive oil for cooking, a little butter on toast in the morning eventually (10-15 micro g = butter restaurant).
  10. Hydrate the body, not to lose weight, but to maintain good health. Drink water daily but also herbal teas or green tea (without sugar)... Limit sodas and fruit juice. Drink Light without exaggeration. Alcohol should always be limited or avoided.


"Corinne Peirano, dietician - nutritionist, is a university graduate in sports nutrition and professor of the university diploma of sports nutrition at the University Hospital Pitié Salpêtrière and our sports nutrition consultant for the Ultra Trail du Mont-Blanc®. She is also an Ultra marathon runner (marathons and trails). She can give you the benefit of her long experience in dietetics and sports nutrition in consultation at her surgery of Dietetics and Nutrition in Paris, or in consultation via email or telephone giving advice on new dietary habits, in your training and on how to improve  your performance in race or as part of a specific sports project."

Corinne PEIRANO Dietician-Nutritionist
Sports Nutrition // Eating Disorders

14 Rue Christophe Colomb 75008 PARIS
Metro Charles de Gaulle-Etoile or George V
Tel: 00 33 1 47 23 47 97 - Email: diet.peirano[at]