Junge Welt: Fat & Sugar – Jan 22, 2026

While in this country people still think of Christmas when they hear “fat metabolism,” the professional cyclists on the Côte d’Azur are uploading their Strava data. Others are already at the start of the Tour Down Under. Tadej Pogačar, who competed in his first professional race there in 2019 and immediately took 13th place, is not scheduled to take part in the event until March this year. You will see him swallow dust on the Tuscan gravel of the Strade Bianche and probably win again. His tremendous dominance in recent years makes this prediction hardly seem daring.

It’s hard to remember that time because Pogačar was just the best in the world – first in the UCI rankings, winner of the Tour de France, strong in one-day races. Since 2024 he has been going one step further. Mathieu van der Poel is at least at eye level in the pavement classics, Jonas Vingegaard is no longer on the same level as the tours, and Remco Evenepoel is not yet at the difficult classics. Pogačar’s biological clock is also ticking. At some point he will no longer be able to maintain the level. Anyone who talks about his dominance should refrain from making historical comparisons. Eddy Merckx, the most successful professional in cycling history, rode under different conditions. Pogačar will never equal his 279 professional victories (108 so far). Training and material were at a different level in the 1970s. Pogačar rarely completes more than 50 racing days per season, Merckx tended to do 90, but in a peloton with a significantly lower performance density. Too many variables. A look at the racing dramaturgy is more interesting. What provokes the comparison with the incomparable in the first place is the way Pogačar wins races. Even at Merckx the script wasn’t set before the race.

With Zone 2 into the crisis

The fact that Pogačar immediately jumped to the top of the world somewhat obscures the fact that his career was not linear. Until 2023 he was only number one in the world, by 2024 his performance data exploded again, and more: his athletic profile changed. It’s hardly a coincidence that this coincides with a change of coach in the winter of 2023. Until then, Pogačar had been trained by Iñigo San Millán. His approach was simply to let the driver drive in the Zone 2 area. This appears to have been effective for a while, but by the end of 2023 Pogačar was in crisis. For the second time in a row he had missed out on winning the Tour and was treading water in one-day races. His new coach Javier Sola turned the setup around. Reducing the weight by one and a half kilograms, building muscle, losing body fat, shortening the crank length to 165 millimeters, which increased the cadence, more training in the time trial position. They also worked on heat adaptation, as Pogačar often had problems at higher temperatures. Another problem was fatigue after altitude training camps, Sola increased the number of altitude blocks and tailored the training to the conditions there. But probably the most important change was the increased proportion of intensive intervals compared to the almost pure zone 2 training at San Millán.

Physiologically, zone 2 means training primarily in the performance range in which the body processes the maximum amount of fat, which is why it is also referred to as “Fatmax”. Training in this area strengthens the muscles of fiber type I (slow-twitch), which have a higher density of mitochondria, contract more slowly and are therefore responsible for endurance performance. As the power plants of cells, mitochondria process nutrients to generate energy. Zone 2 promotes mitochondrial efficiency and density in muscle tissue as well as capillary growth. The fact that there is such a thing as a Fatmax has to do with the metabolism system. In fact, beyond a certain point of exercise, fat consumption not only stops increasing, it actually decreases. This point is the Fatmax.

Endurance and speed strength

In metabolism there are two ways of producing energy, one aerobic (with oxygen) and one anaerobic (without oxygen). In aerobic metabolism, fat is burned using oxygen and ATP is generated, an energy-carrying phosphate. If the load reaches the limit after which the aerobic pathway is no longer sufficient, the anaerobic system takes over the primary energy procurement. Here, in the process of glycolysis, carbohydrates are processed into the end product lactate, which is distributed throughout the body via the bloodstream and processed into energy in the muscle cells. However, the curve of (aerobic) fat metabolism grows linearly, that of (anaerobic) glycolysis exponentially. As the load increases, two processes happen. Fat consumption increases up to a certain point in line with the load, and beyond this point it decreases. Carbohydrate consumption, on the other hand, continues to grow, but not evenly, but in the form of a parabola. This exponential increase (together with the inhibitory effect of H2 ions that arise in glycolysis) explains what seems self-evident to everyday consciousness without any understanding of the connections: that exertion beyond the aerobic threshold cannot be sustained for long.

Now it is not immediately understandable why in the higher performance range, when the anaerobic energy pathway dominates, the aerobic fat consumption responsible for low-threshold endurance performance does not continue to increase. The fat metabolism curve, as I said, then drops. The reason for this is that both systems do not run separately, but are connected. Although fat metabolism dominates at lower levels of performance, it also requires carbohydrates. The first intermediate product of glycolysis is pyruvate, which is further processed into acetyl-CoA and drives fat metabolism. Without carbohydrates, not only glycolysis breaks down, but also fat oxidation. Fatmax does not mean absence of carbohydrate consumption, it simply means the point at which the body burns the maximum amount of fat. The more pyruvate is converted into lactate under high stress and used for anaerobic energy production, the less pyruvate can flow into the citrate cycle as acetyl-CoA and keep the fat metabolism going.

Which makes the disadvantage of pure Zone 2 training clear. Zone 2 is used to develop aerobic capacity, endurance performance, by increasing the Fatmax threshold. For athletes with a high threshold, the consumption of carbohydrates is also higher. The better an endurance athlete is, the more endurance training costs him. Since Zone 2 is more conducive to developing endurance rather than working at a high level of endurance, two problems arise. The athlete runs the risk of losing his speed strength; he expends huge amounts of carbohydrates without the associated training effect on speed strength. And under certain circumstances he can deplete his deeper reserves of carbohydrates without being noticed at first. Both seem to have happened to Pogačar every now and then in the years before 2024: collapses on long mountain stages (latently empty memory), a lack of liveliness, which is an essential element of his driving style.

Even if Pogačar was already considered a strong sprint rider before 2024, he seemed to enjoy this reputation more because of his abilities rather than specific training. In the last two years he made the biggest leaps in speed, after which he not only had an advantage in finish sprints, but also in attacks many kilometers before the finish. His competitor Evenepoel said resignedly after the 2025 European Championships, he can pedal 20 to 40 watts more for a good ten minutes than the rest and recover more quickly from this feat of strength during the race. Thanks to his high endurance performance, he is also able to maintain the lead he has gained until the finish. This is most clearly reflected in the success in the one-day races. In 2025 Pogačar won eight out of ten difficult classics this way, and in 2024 six out of six. “There are no risks with his solo attacks,” his trainer Sola recently packaged the complicated connections into a handy formula.