Nutrition for Climbers: A Guide for Nutrition Professionals

Gines Tello

Graduado en Nutrición Humana y Dietética, certificación ISAK nivel 2. Curso de Nutrición Deportiva en deportes específicos, F. Holway. Curso de Entrenamiento del Sistema Digestivo, Aitor Viribay. Curso en requerimientos de proteína, G. Quesada.

Nutrition for climbers presents a particular challenge for nutrition professionals: achieving favourable body composition and a good strength-to-weight ratio without compromising energy availability, recovery or the athlete’s health. 

When working with climbers in practice, nutrition planning must also reflect the discipline, since the demands of bouldering differ from those of sport climbing or multi-pitch climbing. This guide reviews the main factors professionals should consider when planning and monitoring a climber’s diet.

Introduction

Climbing has grown from a niche sport into a demanding Olympic discipline. It first appeared at the Tokyo 2020 Olympic Games, held in 2021, and consolidated its place at Paris 2024. Climbing is currently growing, with an estimated 44 million climbers worldwide, partly thanks to the Olympics. In Spain, federation memberships exceed 290,000, although participation without a federation licence is much higher because of the growth of indoor climbing gyms.

Nutrition in climbing has evolved enormously, and continues to do so, as physiological demands increase and sound nutrition planning has been shown to affect performance directly. To put this evolution in context: 

• In the 1970s and 1980s, nutrition was a secondary consideration in climbing. Climbers ate whatever they carried in their backpacks, usually tinned foods, cured meats or nuts. Practical experience took precedence over science.

• In the 1990s and early 2000s, climbers increasingly realised that lower body weight made it easier to overcome gravity. This triggered a period of unsupervised restrictive diets, fear of carbohydrates, eating disorders and a high prevalence of relative energy deficiency in sport (RED-S). Although athletes became very lean, finger pulley tears and muscle loss increased exponentially.

• Entry into the Olympic programme and applied physiological research have now changed the approach to climbing nutrition. Modern nutrition is based on energy periodisation: the aim is to be strong and functional rather than simply thin. Today, the focus is on optimising energy availability, protecting tendons and maximising relative strength without compromising hormonal health or performance.

Working with climbers is a real challenge for nutrition professionals: we need to balance the lightness required to overcome gravity with the explosive strength and energy demanded by routes and boulder problems. This post discusses the key connections between nutrition and climbing.

The physical demands of climbing: strength, endurance and body composition

Body composition in climbing is shaped by the principle of relative strength: maximising applied force while minimising non-functional body weight. The scientific literature describes a very specific morphological profile among elite climbers, characterised by low fat mass, moderate and functional muscle mass, and skeletal proportions that provide a mechanical advantage.

Body fat acts as dead weight that gravity penalises on overhangs and difficult moves. The literature consistently shows a negative correlation between body fat percentage and the maximum climbing difficulty achieved.

However, body fat percentage has a safety limit. Falling below physiological ranges such as <5% in men or <10–12% in women exponentially increases the risk of relative energy deficiency in sport (RED-S), stress fractures, loss of bone mineral density and impaired immune function. These can lead to injury or illness, directly affecting the athlete’s health.

Generalised muscular hypertrophy is unfavourable in climbing because of the weight penalty. Elite climbers show highly localised muscle development in the deep and superficial finger flexors, forearm pronators, latissimus dorsi, teres major, posterior deltoid and core muscles. Maintaining a small or moderate thigh and calf circumference is advantageous to avoid adding extra lower-body weight beyond the muscle tone needed for pushing.

One proportion that can make a difference in climbing is the ape index: the ratio of outstretched arm span to total height. It is one of the few purely genetic anthropometric factors positively correlated with sporting level. A neutral ape index is 1, meaning arm span equals height. Among elite climbers, an index >1.03 is common, with arm span 3 to 8 cm greater than height. This reduces the torque needed to reach distant holds and helps keep the centre of gravity closer to the wall.

Although climbers’ anthropometric profiles may look similar at first glance, there are significant differences depending on their discipline. Each discipline’s biomechanical and energy demands produce different anthropometric adaptations. Let us examine some differences between bouldering and sport climbing.

Bouldering requires peaks of maximal force and extreme explosiveness in sequences of 3 to 8 moves. This calls for more muscle mass in the torso, shoulders and back. 

Route climbers face efforts lasting 2 to 10 minutes. Cardiac output and progressive neuromuscular fatigue mean that any excess muscle mass adds an oxygen demand that cannot be sustained over 30 or 40 metres of wall.

Bouldering involves slightly greater lower-body mass because of jumps, aggressive heel hooks and powerful pushes through the feet. In sport climbing, the lower body is deliberately kept extremely lean to reduce the moment of inertia during rests and slab moves. 

Later sections explain how nutrition planning differs according to the climbing discipline and the optimal body composition required.

Nutritional goals for climbers

As discussed, both muscle mass and fat mass are important considerations in climbing. Nutrition professionals can monitor these variables through adjustments to the nutrition plan. Athletes need to understand that skeletal proportions cannot be changed and will place limits on muscle gain and on how far body fat can be reduced.

When designing the athlete’s nutrition strategy, the priorities should be:

• Maintaining muscle mass and strength while pursuing optimal body composition. For some profiles, reducing muscle mass may also be a goal.

• Optimising glycogen stores for long training sessions or full days on the rock. Depending on the discipline, loading more carbohydrate the day before or fuelling during activity may be more useful.

• Ensuring rapid recovery between training sessions. Depending on the training structure, this means supporting glycogen replenishment, ensuring adequate daily protein intake and properly replacing sodium lost through sweat.

However, as mentioned earlier and explained in more detail below, climbing includes different disciplines with different anthropometric characteristics and therefore different nutrition planning needs. We will therefore outline discipline-specific strategies.

• Bouldering: focus on power and recovery between problems.

This discipline does not require massive glycogen loading because efforts last only seconds or minutes. However, rapidly absorbed carbohydrates such as fruit, dates or maltodextrin are needed before and during sessions to maintain mental focus and peak intensity during dynamic moves.

Adequate protein intake is important because powerful eccentric movements, one-arm lock-offs and landings on mats can cause muscle microdamage.

• Sport climbing: focus on lactate tolerance and lightness.

Carbohydrates are the critical macronutrient in this discipline. Thirty-metre routes quickly deplete glycogen because of their high intensity and demands. Periodisation with high intakes is required on these days.

Protein remains important, with a focus on tissue maintenance and recovery without stimulating non-functional hypertrophy, especially in the lower body or chest.

All these recommendations must be individualised according to the athlete and their body composition goals. Later sections discuss macronutrient distribution for each discipline in detail. Total energy intake must be considered to determine suitable ranges for each macronutrient. Selecting foods for a 1,800-calorie plan is very different from planning a 3,000-calorie diet: this is where the nutrition professional’s skill in optimising the plan becomes essential.

How to adjust energy intake without compromising performance

The major dangers in climbing are low energy availability (LEA) and relative energy deficiency in sport (RED-S).

Many climbers chronically restrict calories to become lighter. Over the medium and long term, this can disrupt hormonal function, weaken bones and increase the risk of tears and fractures.

Relative energy deficiency in sport (RED-S) develops when energy availability (EA) falls below 30 kcal/kg of fat-free mass per day. Nutrition professionals need to keep this value in mind when planning meals to ensure that the plan cannot lead to RED-S.

Consistent nutrition education is important for changing a calorie-restriction mindset where one exists. Helping athletes understand the potential danger to their long-term health and giving them the tools to manage their diet at all times is an important part of our role.

Nutrition periodisation can be especially important in climbing. Eating patterns should not be identical every day. On demanding or long training days, the body needs sufficient energy, with carbohydrates prioritised because of the sport’s demands. On active recovery or lower-intensity days, an energy deficit may be considered if the goal is to improve body composition by reducing fat.

Nutrition periodisation involves more than adjusting calories to daily energy needs. It also requires appropriate distribution of macronutrients, micronutrients and supplementation according to the stage of the season and current goals.

Nutrition before, during and after climbing

Meal timing can make the difference between completing a training session successfully and stopping halfway through because of insufficient energy. As discussed throughout this post, different climbing disciplines require different strategies. The following are general recommendations to help athletes start with full glycogen stores and recover well. Depending on the nutrition professional’s strategy or the stage of the season, another specific approach may be more appropriate.

• Before a climbing session

Around 2–3 hours before climbing, prioritise a meal rich in easily digested complex carbohydrates, moderate in protein and very low in fat and fibre to avoid stomach discomfort. Pre-session fibre intake should also be tailored to the athlete’s tolerance and usual intake, although reducing it is advisable.

Suitable foods include rice, pasta, bread or gnocchi for carbohydrates; chicken breast, tuna, tofu or eggs for protein; and olive oil or avocado for fat. 

Try to avoid high-fat protein sources, large amounts of vegetables and added sauces. If climbing outdoors in extreme heat, adding a pinch of iodised salt to the main meal may be advisable.

• During long training sessions or days on the rock

If the session lasts more than 90 minutes, as is often the case, it is advisable to take in energy during rest periods.

Suitable foods include bananas, dates, fruit bars, quince paste, sports gels or isotonic drinks. For activities lasting several hours, such as traditional climbing, carrying energy-dense foods such as jam and peanut butter sandwiches, nuts or other savoury options is recommended.

Timing matters: eat small portions immediately after coming down from a route or a hard bouldering attempt, allowing time for digestion before the next effort.

• After climbing

After climbing, the goals are both glycogen replenishment and tissue repair.

Depending on the session’s demands and duration, a recovery shake immediately afterwards may be advisable, with a carbohydrate-to-protein ratio ranging from 4:1 to 2:1.

Provide rapidly absorbed carbohydrates as soon as possible, together with 15–20 grams of protein in the following hours. For better recovery, several smaller carbohydrate servings over the next 4–6 hours, while still meeting total requirements, may be preferable to one very large intake.

Hydration and electrolytes in climbing

Proper hydration is particularly important in climbing, especially in disciplines involving direct sun and heat exposure or repeated intense efforts over several hours.

Dehydration reduces grip strength and coordination, both crucial for performance and safety in climbing. In the mountains, athletes are fully exposed to environmental conditions:

• Wind and cold can mask the sensation of sweating, and it is common to go for long periods without hydrating properly.
• Hot days and extreme heat can produce very high sweat rates that are not adequately replaced.

In both cold and hot conditions, athletes need to understand the importance of following a specific hydration plan and recognising their needs at each stage.

Hydration management in climbing is critical. Losing just 2% of body weight as water can reduce grip strength by 10–15% and seriously impair rapid decision-making on the wall. Thirst should not be relied on: in climbing, it appears after performance has already declined. We can teach athletes to use the following guidelines to assess hydration:

Before climbing: urine colour assessment (Armstrong scale)

• Hydrated (levels 1–3): Light straw or pale yellow. This indicates that fluid and cellular stores are full.
• Dehydrated (level 4 or higher): Dark yellow or orange urine, or a strong smell. This means the athlete should immediately drink 300–500 ml of water with electrolytes at least 60 minutes before warming up.

After climbing: monitoring body weight loss

• Weigh before and after: Ask the climber to weigh themselves barefoot before the session and again afterwards.
• Calculating the deficit: Every 0.5 kg of weight lost corresponds to half a litre of evaporated fluid.
• Rehydration rule: To fully restore fluid balance, the climber should drink 150% of the weight lost over the next 2–4 hours. For example, if they have lost 1 kg, they should drink 1.5 litres of fluid.

Other general recommendations for managing hydration in climbing include:

• Avoid plain water alone during long sessions because of the risk of hyponatraemia. Drinking large volumes of water without electrolytes dilutes blood sodium, causing headaches, loss of strength and swelling. For training sessions longer than 90 minutes, always add 500–700 mg of sodium per litre of water, or an electrolyte tablet.
• Make use of the food matrix: On climbing days or demanding approaches, include foods high in water and potassium in earlier meals, such as watermelon, melon, oranges, cucumber or cold soups such as gazpacho, which also provides naturally occurring sodium.
• Pre-hydration: On the day before a demanding rock project, the climber should ensure an intake of 2–3 litres of water spread throughout the day. Starting a climb while trying to correct dehydration from the previous day is an irreversible mistake.

Useful supplements for climbers

As discussed earlier, climbing disciplines differ greatly in physiological and anthropometric terms. We will also distinguish which supplements may be useful and offer additional benefits for each type of climbing.

Bouldering:

• Creatine monohydrate (3–5 g/day): The leading supplement for bouldering. It increases phosphocreatine stores to maximise peak power during the hardest attempts. It may also support glycogen resynthesis for recovery between sessions.

• Caffeine (3–6 mg/kg): A useful pre-training supplement for maintaining focus, which also increases motor unit recruitment and rapid muscle force. It should be taken 45–60 minutes before the most intense efforts.

• Collagen and vitamin C (10–15 g and 50 mg): Often recommended 45 minutes before training to protect finger pulleys and tendons from high mechanical impact.

Sport climbing:

• Beta-alanine (3.2–6.4 g/day): Divide the intake into several doses to avoid paraesthesia. This supplement raises muscle carnosine levels and acts as an intracellular buffer, delaying forearm burning during long sequences.

• Beetroot juice/nitrates (300–400 mg): A natural vasodilator that improves blood flow and oxygen delivery to the small forearm muscles. It should be taken around 2–3 hours before exercise.

• Electrolyte drinks (sodium): Maintain optimal hydration on sun-exposed walls and prevent dehydration-related loss of grip strength.

Common mistakes in climbers’ diets

Climbers can make many dietary mistakes, most stemming from limited nutrition knowledge. Nutrition education from the outset is therefore important, with detailed explanations of potential errors. Below are four important examples.

• Chronic calorie restriction and low energy availability (LEA)

Becoming obsessed with body weight and maintaining a prolonged deficit to become leaner is a mistake. This is common across sports, particularly those in which weight directly affects performance.

In a sport where gravity is the opponent, there has historically been pressure to maintain minimal body weight. This leads many athletes into LEA, whether deliberately through restriction or unintentionally by failing to meet training energy expenditure, triggering relative energy deficiency in sport (RED-S).

This brings a drastic reduction in performance, loss of functional muscle mass, hormonal disturbances such as reduced testosterone and amenorrhoea (loss of menstruation), lower bone mineral density and a sharply increased risk of tears and tendon injuries because of impaired tissue repair.

• Fear of carbohydrates

Carbohydrates are eliminated or drastically reduced because they are thought to cause weight gain or to be unnecessary in a sport that is not a traditional cardiovascular activity.

The result is depletion of muscle and liver glycogen without subsequent carbohydrate replenishment. This causes premature central fatigue, loss of explosive strength in bouldering, reduced tolerance of lactate accumulation and earlier fatigue on sport routes.

• Poor food planning at the crag

Not eating enough during a session, whether at an indoor gym or in the mountains: spending 6 to 8 hours consuming only water, coffee and perhaps some fruit or a handful of nuts.

This can lead to progressive hypoglycaemia towards the end of the day, a sharp loss of mental focus that increases the risk of bad falls or route-reading errors, and accelerated muscle breakdown.

• Overusing stimulants to mask a genuine energy shortage

This mistake is linked to the previous ones. When calorie intake from carbohydrates or nutrient timing is inadequate, stimulants such as caffeine, energy drinks or other pre-workout products are used to feel stronger.

This can lead to chronically elevated cortisol, disrupted sleep that prevents skin and tendon regeneration, and a false sense of energy while glycogen stores remain empty.

How to adapt nutrition to the type of climbing

As discussed earlier, different climbing disciplines require very different anthropometric profiles. Nutrition must therefore be adapted to the athlete to help achieve the optimal body composition for their specialty. Starting conditions and potential limitations must be considered, with nutrition adjusted to optimise body composition without harming performance or health. 

Below, we outline key details of each climbing discipline and relevant nutrition strategies.

• Sport climbing

Sport climbing involves ascending routes of 15 to 40 metres protected by bolts and carabiners. The main physiological challenges are lactate accumulation in the forearms and managing metabolic fatigue during continuous high-intensity sequences.

Sport climbers need full glycogen stores to sustain prolonged efforts and delay fatigue. Carbohydrate intake should be higher than in bouldering, with around 5–8 g/kg/day providing a high, consistent supply throughout the day. At least 1.2 g/kg/day of protein would be sufficient for muscle repair after training without promoting excessive hypertrophy. Compared with bouldering, reducing fat to 0.8 g/kg/day is recommended, remaining within a healthy intake while leaving more calories available for carbohydrates.

• Bouldering

Bouldering is the ultimate expression of pure strength and explosive power. Climbers move without ropes on boulders or low walls up to 4–5 metres high, protected by mats. Nutritional demands centre on the phosphagen system, joint health under impact and rapid recovery between attempts requiring maximal neuromuscular intensity.

Boulderers depend on explosive strength, power and ATP recovery between attempts. A recommended carbohydrate intake may be 3–5 g/kg/day, prioritised around the session, both before and after. For protein, ensuring 1.5 g/kg/day is a sound recommendation to support muscle synthesis and strength. Fat intake should not fall below 1 g/kg/day to support hormonal and metabolic health.

• Traditional or multi-pitch climbing

Traditional climbing is a test of aerobic endurance, mental strength and logistics. Linking multiple rope lengths over hours or entire days in the mountains changes nutritional needs dramatically. Priorities become energy-dense foods, long-term glycogen preservation and consistent hydration in potentially extreme environmental conditions.

Nutrition planning is entirely different from the other disciplines. The challenge is to carry enough calories without excessive weight for the expected duration. Highly energy-dense foods that take up little space are particularly important. They should mainly provide carbohydrates, but high-fat foods such as nuts also have a place because of their calorie content.

Example meal plan for climbers

As discussed, each climber has different nutritional requirements, macronutrient distribution and goals. It is therefore impossible to compare two meal plans directly or create one universal plan. This section provides recommendations and examples for selecting and combining foods in a typical menu. The meal plan is described as 2,500 kcal and uses the following macronutrient proportions:

• Carbohydrates (60%): 375 g (1,500 kcal): Maximum glycogen replenishment and energy availability.
• Protein (20%): 125 g (500 kcal): Muscle fibre repair and collagen synthesis without excessive bulk.
• Fat (20%): 55 g (500 kcal): Hormonal support tailored to the performance profile.

This menu includes options for both omnivorous and vegetarian athletes.

Breakfast (600 kcal)

• Omnivorous: Porridge made with oats (60 g) and almond drink (150 ml), plus 2 whole scrambled eggs and 1 egg white, 1 large banana and 10 g of honey.
• Vegetarian: Porridge made with oats (90 g) and soya drink (250 ml), plus 15 g of plant-based protein powder, 1 large banana and 10 g of chia seeds.

Before training (150 kcal)

• 200 ml of fresh orange juice.

During training (150 kcal)

• 1 litre of water with electrolytes (500 mg sodium), plus 50 g of pitted dates, approximately 5–6 dates.

Lunch (800 kcal)

• Omnivorous: Basmati rice (140 g dry weight), 120 g grilled chicken breast, stir-fried vegetables with 10 g extra virgin olive oil, and 150 g fresh pineapple.
• Vegetarian: Couscous or quinoa (140 g dry weight), 150 g grilled firm tofu with sautéed vegetables and 10 g extra virgin olive oil, and 150 g fresh pineapple.

Afternoon snack (500 kcal)

• 2 slices of sourdough toast (80 g) with 15 g peanut butter, 1 sliced apple and cinnamon.

Dinner (500 kcal)

• Omnivorous: 140 g grilled salmon or hake, 250 g baked potato or sweet potato, and a mixed green salad with 8 g extra virgin olive oil.
• Vegetarian: 200 g cooked chickpeas or lentils, 250 g baked sweet potato with 30 g avocado, fresh spinach and 8 g extra virgin olive oil.

How to monitor nutrition in climbers

Nutritional follow-up for climbers requires a multidimensional approach. Focusing solely on weight or the scales is ineffective and dangerous because of the high risk of triggering eating disorders and relative energy deficiency in sport (RED-S).

Rigorous monitoring should combine performance variables on the wall, functional anthropometric measures and systemic health markers.

• Perceived recovery speed: Use rating of perceived exertion scales (RPE from 1 to 10) the day after high-load sessions. If the athlete reports persistent muscle heaviness or finger pulley pain from one session to the next, review energy intake around training and protein intake throughout the day.
• ISAK anthropometry (limiting the focus on weight): Use the sum of 6 skinfolds—triceps, subscapular, supraspinale, abdominal, front thigh and calf—instead of net body weight. The aim is to keep athletes within healthy adiposity ranges of 30–45 mm in men and 45–60 mm in women while ensuring they do not lose functional upper-body muscle mass.

RED-S warning signs

• Hormonal health: Amenorrhoea or oligomenorrhoea in women. Reduced libido or sexual dysfunction in men.
• Sleep quality and mood: Difficulty falling asleep, irritability, apathy or rigid obsession with food weights, which may indicate the development of an eating disorder.

Regular blood tests: Request panels every 3–6 months assessing:

• Iron status: Ferritin and transferrin. Iron deficiency is very common in female climbers because of calorie restriction and menstrual bleeding.
• Hormonal axis: Free testosterone, free triiodothyronine (T3), which is sensitive to calorie deficits, and basal cortisol.
• Bone and metabolic health: Vitamin D (25-OH), vitamin B12 and a full lipid profile.

Conclusion

Climbing nutrition means eating strategically to climb more and better, rather than eating less simply to weigh less.

Our role as nutrition professionals is to challenge myths about calorie restriction in this sport, teach nutrient periodisation for each discipline—bouldering, sport climbing or multi-pitch climbing—and give athletes the fuel they need so that gravity, rather than a lack of energy, is their only limit on the wall.

Frequently asked questions about nutrition for climbers

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