Sabastian Sawe reached the halfway point of the 42.195km run in 1 hour and 29 seconds. By all conventional logic, the second half should have been slower. It is almost always the case in marathons. From that point on, it stops being about speed and becomes a question of fuel, of how long the body can hold the line before it runs empty.But Sawe, 30, didn’t follow that script. The Kenyan held his pace deep into the race and got faster, as he became the first person to break the two-hour barrier in an official marathon on Sunday, winning the London Marathon in 1:59:30.The groundwork for this had been laid hours earlier: a simple breakfast of two bread slices with honey and tea, followed by a meticulously planned in-race strategy that delivered up to 115 grams of carbohydrates per hour, an amount once considered difficult for the body to tolerate.In a marathon, long before the legs give way, the body faces a subtler crisis. Glycogen, the stored carbohydrate that powers sustained effort, is finite. At an elite pace, it drains fast. And when it’s gone, the slowdown is abrupt, punishing. Runners call it “the wall”, but it’s really a fuel failure.The obvious solution, to consume more carbohydrates mid-race, has always come with a catch. Carbs help build energy, but the gut can only handle so much. Push beyond that limit, and the stomach revolts.Also read | Sabastian Sawe runs 1:59:30 — the grandmother who won’t see it“So, the companies started making a concentrated carbohydrate source, which is a gel,” said Mihira Khopkar, who was the Indian contingent’s nutritionist at the 2024 Paris Olympics. “However, it causes gastrointestinal (GI) upsets among the athletes because it can sit in their stomachs, making them feel bloated, heavy and uncomfortable. Some even complained of diarrhoea, because there is no blood supply to the gut – all the blood supply is to the muscles.”Technological advancementsSawe consumed these gels at regular intervals and pushed those very boundaries. But with a difference: the technology used in the gels he consumed changed how the body received the carbohydrates.Story continues below this adThe hydrogel he had combines alginate, derived from seaweed, and pectin, a natural fibre found in fruits, to form a protective gel matrix. Khopkar explained that in this semi-solid state, the hydrogel behaves much like a sponge, its structure filled with microscopic pores that hold and transport concentrated carbohydrates efficiently through the digestive system. “Those carbohydrates are made available to use as energy,” Khopkar said.NewsletterFollow our daily newsletter so you never miss anything important. On Wednesday, we answer readers' questions.SubscribeMaurten, a Swedish sports nutrition brand, developed this technology. Plan measured in minutesSawe’s run was built on this principle of controlled, continuous fuelling. Sports scientists from Maurten developed Sawe’s fuelling protocol over the last 12 months, when they made six trips to Kenya, spending 32 days there with him. They also developed a personalised gut-training plan and a race-day protocol to enhance Sawe’s GI tolerance for carbohydrate intake on a race day.Additionally, Sawe also used sodium bicarbonate to neutralise the lactic acid buildup that causes the burning sensation in muscles.Story continues below this adOnce the race began, his strategy was almost metronomic. Every 20 minutes, aligned with aid stations, he took a hydrogel. Not reactively, not when fatigue hit, but proactively, before the body could dip into deficit.Also read | He came, he Sawe, he conquered history: Sabastian Sawe runs marathon under 2 hoursAccording to Joshua Rowe, head of sports tech at Maurten, Sawe drank 160 ml of the carbohydrate drink at 5, 10, and 15 km. At 20 km, he took a caffeinated energy gel along with a 160 ml capsule of the drink. Caffeine sharpens focus and dulls the sensation of effort. And at 25, 30, 35 and 40 km, he had more of the carb mix, each of 160 ml.Rowe said this kind of gut capacity had to be trained, which they did by mimicking his exact race-day schedule. “This was aimed at progressively conditioning his gut, reducing the risk of GI distress,” Rowe was quoted as saying.The effect was subtle but decisive: a steady stream of glucose into the bloodstream, no spikes, no crashes, no panic late in the race. While others risked fading, Sawe maintained equilibrium.Holding the lineStory continues below this adAs the race entered its decisive phase, Sawe was managing momentum. His glycogen stores, though heavily taxed, had not emptied. His muscles still had access to fuel. His mind remained clear, his stride controlled.He covered the distance from 20 to 25 km in 14:47. Last year in Berlin, he covered that distance in 15:05. His final 10 km were even quicker: he covered it in 28:53 in London, compared with 29:14 in Berlin.Sawe sped towards the finish line at an average pace of 2.50 minutes per km. And by the time he crossed the tape, he’d achieved sporting immortality. The hours Sawe put in training, running 30 km daily, showed that training still built the engine. But fuelling now determines how long it can run at full power.