The role of sports nutrition in endurance sports – What, when, and how much?

It wasn't that long ago when fueling at the Tour de France meant little more than riders drinking. Water, sugar water—and that was that. You have to rewind even further to the era when they drank beer, but even that happened. In contrast, today a full team of dietitians calculates the evening menu and macronutrient ratios to the gram, and perfect on-bike fueling has become an integral part of the strategy. In the current pro peloton, the only ones with a chance of survival are those who can digest and utilize at least 120–140 grams of carbohydrates per hour. To put that into perspective: that’s roughly like drinking a 0.33l Coke every 15–20 minutes, or eating three cups of white rice every hour.

It’s hard to even wrap your head around, and naturally, a hobby cyclist shouldn't experiment with such quantities. However, it’s clear that sports nutrition isn't just a trend; it’s a logical extension of training. It’s no coincidence that anyone who has ever followed a health-conscious page or sports brand on social media is practically bombarded with nutrition advice—often with completely contradictory messages every six months.

Yet, what counts as healthy for a sedentary lifestyle is far from ideal for someone training 12 hours a week.

Build from the Foundations

Anyone who wants to improve—or simply stay within healthy boundaries—cannot stop at planning the duration and intensity of their workouts. You must build your pre-, intra-, and post-workout meals with the same conscious effort. And yes: unfortunately, even on rest days, you can't get away with a "double lángos" followed by a cream cake without consequences.

Sports nutrition only works if the foundations are solid. You need to understand the roles of fats, proteins, carbohydrates, and fiber in the human body, and how hydration ties into it all. Only on this foundation can you build a performance-enhancing strategy. There are general guidelines, but there is no "one-size-fits-all" recipe. You won't find a universal list of exactly what to eat from Monday breakfast to Sunday dinner. If you do, be suspicious.

The equation is modified by many factors. For example: in women, the cyclical changes of the hormonal system influence nutritional needs—especially over the age of 35. During the luteal phase, cravings for sweets and fatigue are more common, and the diet may require more carbohydrates. Elevated core temperature also affects thermoregulation and fluid requirements, meaning energy and hydration strategies must be fine-tuned to the cycle. Metabolism also differs by gender: women tend to utilize fatty acids better, while men generally favor carbohydrates.

Besides age and gender, factors like sensitivities, taste, lifestyle, and how you distribute your weekly training volume are all crucial.

“Food first… but not only!” – Supplements that actually work

Social media "gurus" and strict celebrity dietitians often hype certain foods while banishing others to a permanent blacklist. They also frequently offer supplements as a silver bullet. The fact is, there are supplements proven to be effective and safe for performance: creatine, bicarbonate, beta-alanine, caffeine, and nitrates.

For instance, creatine can be particularly useful for a vegan athlete—it might be the key to their explosiveness—but its use isn't a universal requirement. Omega-3 fatty acids and various vitamins support general health and play a key role in recovery. Their use is justified if the base diet doesn't cover the requirements—for example, for those who rarely eat oily fish.

The point remains the same: performance doesn't depend on a handful of "miracle pills" ordered from various webshops, but on whether supplements respond to real deficiencies and specific goals.

The Real Work: Carbohydrates

Current scientific consensus suggests that utilizing approximately 120g of carbohydrates per hour is key to optimal performance—some can process even more, up to 200g. Turning this into kinetic energy isn't automatic: the amount must be built up gradually and tested in training while the digestive system adapts to the load.

As a workout progresses—especially around the second or third hour—energy expenditure accelerates. Not only do muscle carbohydrate stores empty, but liver glycogen levels drop as well. This is when classic fatigue symptoms appear: irritability, loss of focus, and the gradual "draining" of the central nervous system.

Even knowing the theory is no guarantee of success. In practice, many fail because the body simply cannot digest and utilize the recommended amount of carbs under stress.

Furthermore, the type of challenge matters. In an "ultra," you have to "feed" the body differently so that energy keeps flowing without losing your appetite—and your will to live. Conversely, in a high-intensity one-day event with a 190 bpm heart rate, you don't just have to remember to fuel; you actually have to swallow the gel and take in the right amount of fluid.

This task is far from trivial. In endurance sports, blood flows primarily to the working muscles, not the digestive system. Blood supply to the gut decreases, the transport of intestinal contents slows down, and the rate of digestion and absorption changes—this is where most GI discomfort stems from. The digestive system is under stress, yet it’s expected to provide energy seamlessly to keep the legs turning.

Gels are an efficient and easily dosed solution, but they contain preservatives for shelf life. Regular, large-scale consumption isn't ideal in the long run, so it’s best to save them for race situations. During everyday rides, bars are better—especially those that aren't chocolate-coated and don't contain emulsifiers or stabilizers. The best, of course, are homemade rice cakes or fruit muesli bars.

Expectation vs. Reality

All of this might seem like a dream world on the fourth day of an ultra-race, standing in front of the half-empty shelves of a village grocery store—among anonymous wafers, gummy bears, and isotonic drinks the color of windshield wiper fluid. The good news is that in such moments, you don't need to overanalyze the packaging: just look for the product with the most sugar and the least fat and protein.

It also helps to look at the "track": before a massive climb, choose a pulpy or liquid solution over a hot dog, unless you want your solid food to become "animal feed" on the side of the road. However, strategically bagging a hot dog, sandwich, or pastry for later, flatter, and leaner sections is a pro move.

Bananas, oats, dried fruits, or rice would be better, but during or before high exertion, the goal is to spike blood sugar and get nutrients quickly to the working muscles, liver, and brain. This logic is the exact opposite of what we would follow for a healthy, sedentary lifestyle, where the goal is to slow down blood sugar spikes.

The takeaway? Food isn't inherently "good" or "bad"; it becomes so based on quantity, timing, and load. White sugar, for example, isn't poison—in the body of someone who actually uses it, it is a highly functional fuel.

Water + Salt: Don't just "Wash Yourself Out"

Once the food is sorted, you're still not done. You can hydrate poorly too. Water alone is often not enough; in fact, if you only drink water, you might "wash out" your system, depleting essential minerals. Fortunately, newer generation isotonic drinks are much better tolerated (and taste better), putting less strain on the stomach while quickly replacing lost fluids and minerals.

As a general guideline, 600ml of fluid per hour is recommended, though in extreme heat, up to a liter may be necessary. It’s worth knowing your individual sweat rate, as needs depend heavily on body type, weather, and intensity.

Don't overthink salt intake: isotonic drinks and gels already contain sodium, so hobby athletes generally don't need separate salt tablets. On ultra-distances, however, salt loss can be a key factor in avoiding muscle cramps—which can also be caused by magnesium deficiency or rising lactate levels. In these cases, along with proper hydration, stretching and certain supplements like beta-alanine can help you survive cramp-free.

Post-Workout: The Reward (Protein)

Now comes the well-deserved reward: Carbohydrates! Yes, again. For fast recovery, you need to replenish both fluids and glycogen. Carbohydrates are crucial for refilling muscle stores, so in the first hour after training, choose fast-absorbing sources—like ice cream, porridge, or an isotonic drink. Proteins, meanwhile, support the repair of muscle micro-tears.

After major exertion, cravings are natural: the body wants to rebuild itself, sometimes for days. But try not to binge indiscriminately just because you feel you "deserved it." That leads to weight gain, followed by tears.

Instead, stick to normal meals: proteins, fats, and complex carbs, such as olive oil and whole grains. As a general guide, consuming 20g of protein 4–5 times a day is appropriate, but needs vary based on body mass and intensity. While the WHO recommendation for a sedentary person is 0.8g of protein per kg of body weight, for an endurance athlete, the optimal value is 1.2–1.6g, adjusted to training days—just like carbohydrate intake.

The source of protein matters too. Not all animal products are the best solution. Digestibility and amino acid profiles count; for example, whey is the most efficient, but soy, pea, or rice protein also fits well into the system. A 50-50 split between plant and animal sources is often best for the efficient utilization of essential amino acids. As we age, muscle breakdown increases, so protein intake becomes even more critical.

Caloric Deficit – Not just for Climbers (Fat)

If you’re planning significant weight loss, the body can be gently taught to utilize fat. Fasted workouts, for example, can contribute to fat adaptation, helping the body prioritize fat for energy. The "train low, sleep low" strategy works on a similar principle.

These are effective methods, but they are sensitive processes that require monitoring; gradual progress and awareness are key. Weight loss requires patience; a 25kg surplus didn't appear in two months, so don't expect it to disappear in that time either.

Approach fat in sports nutrition much like a healthy general diet: it’s essential, but quality matters. Roughly 1g of fat per kg of body weight daily is sufficient (for fat-soluble vitamins), but emphasize mono- and polyunsaturated fatty acids from vegetable oils, seeds, and fish. Limit foods rich in saturated fats, like salami, butter, or heavy cream.

Summary

In the world of nutrition trends, "big claims" often lack footnotes. One post says a vegan lifestyle is best; another says you must consume carbs in any quantity. In this noise, a critical mindset is vital. Project information onto your own life and seek reliable sources. The more dramatic a promise sounds, the more reason there is to verify it—whether with a dietitian, evidence-based digital tools, or AI.

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