Your legs can go longer than your stomach lets them. TrainedGut is a personalised protocol that raises how much carbohydrate you can take in during a race, built from peer-reviewed research, run in the weeks before each race that matters.
Launching for the 2027 season. Everyone on the launch list gets a discount when we go live.
Two emails before launch. One when we go live. That's it.
The pattern
This is the most common reason strong athletes fade in the back half of a long race.
The trade-off
The gut adapts to what it's regularly asked to do. That adaptation is what the protocol trains.
The science
Past two hours of racing, carbohydrate availability — not fitness — is what starts to fail first. Feed the gut more carbs regularly and it builds the transporters to absorb them.
Every claim below links to the paper it came from. Four studies, all published since 2017, all in endurance athletes.
Sports Medicine · Costa et al., 2025 · SDA / Ultra Sports Science Foundation position statement
Up to 93% of ultra-endurance athletes report GI symptoms during their events. Two sports-dietetics bodies now list gut training among strategies with consistent beneficial outcomes.
Sports Medicine · Martinez et al., 2023 · Systematic review
Across eight trials of gut training: gut discomfort down 47%, carbohydrate malabsorption down 45-54%, total GI symptoms down 60-63%. Protocols used carbohydrate gels every 20 minutes at 90 grams per hour.
European Journal of Applied Physiology · Podlogar et al., 2022
At very high hourly intake, shifting the glucose-fructose ratio from the classic 2:1 toward 1:1 raised how much fuel athletes actually absorbed - with no difference in GI comfort.
Performance Nutrition · Podlogar et al., 2025
Personalised carbohydrate feeding delivered the same fuel oxidation on 28% less carbohydrate, with lower stomach fullness and lower perceived effort in trained athletes.
What the evidence doesn't say
Two weeks of very high carbohydrate plus gut training produced no extra performance benefit in elite race-walkers, and slightly more GI symptoms (King et al., 2022). A 2025 review argues the evidence for ≥100 g/h improving performance is still limited (Wilson). We think the failure mode in both cases is "more carbs for everyone" - the opposite of a progressive, individual protocol. But you should know the argument exists.
How it works
Race, date, current gel-per-hour habit, past GI history. The data is used to set your starting dose.
A week-by-week gel plan starting slightly below your current tolerance and adding no more than 10 grams per hour every two to three weeks.
The gels for the next phase only - Foundation carbs first, then Build, then Race-Specific. Each pack labelled by the week.
After each long session, note how it went. A rough block holds the dose; a smooth one adds up to 10 grams per hour.
On race day, take the load you already hit in training - the one you tested on your last long session. No new experiments.
Sample program
Example: a 16-week Ironman build for an athlete currently taking 45 grams per hour. A 10-week half-marathon build looks different - fewer weeks, and a lower target load.
There is no universal number. What your gut can handle depends on how long you'll be racing, how hard, how big you are, your sport, the weather, and where you're starting from. The protocol finds your ceiling and raises it. It doesn't push you toward someone else's.
Weeks 1-3 · Foundation Phase
Starting from you
Your current intake is your starting point. We establish your baseline, identify sensitivities, and build the habit.
Weeks 4-8 · Build Phase
Progressive overload
Carbohydrate load increases week by week. Gut transporters adapt. Multi-source carbohydrate ratios introduced.
Weeks 9-13 · Race-Specific Phase
Race-intensity fuelling
Simulate your exact race conditions. Practise your race-day intake until it feels effortless.
Weeks 14-16 · Taper & Race
Confidence & confirmation
Reduce volume, lock in race-day strategy. By race morning, the load you'll hit is a load you've already trained for.
The people
Lukas
MSc PE, BSc physiotherapy, BSc computing
I ran a 1:18 half marathon while eating almost nothing. I was afraid of sugar and afraid of racing with a full stomach, so I under-fuelled for years and called it discipline. When I finally tried to fix it, my gut couldn't take it. Tolerance is trainable, and almost nobody trains it on purpose.
What I do: I'm not a nutritionist. What I bring is how the body adapts to load, how to build a progression, and how to turn it into software.
![[PLACEHOLDER: nutritionist full name and role]](img/nutritionist.jpg)
[Nutritionist name]
[e.g. RD, MSc Sports Nutrition, PhD]
[Nutritionist bio, 2-3 sentences, first person. Match the voice of Lukas's bio above: concrete, direct, no hype vocabulary. Example: what they've seen go wrong in the field, a moment that changed their thinking, or what drew them to gut training specifically.]
What I do: [Specific role: wrote the progression rules, or reviews each protocol, or sets the safety ceilings. Pick the true one and name it.]
The fair question
You can. The rules are public. Start slightly below your current tolerance, add up to 10 grams per hour every two or three weeks, hold when a session goes rough, shift the glucose-to-fructose ratio as the dose climbs, and don't try anything new in the last two weeks.
The catch is holding that line for sixteen weeks while your training changes, the race gets closer, and every long day is a chance to overshoot and set yourself back a fortnight. The protocol isn't information. It's the week-by-week structure that keeps the progression honest.
Is this for you
If you're on the right and want to be on the left, the honest answer is wait for the next race in your calendar. The protocol needs weeks, not days.
What you get
Before launch
Before launch we're running the protocol with a small group of athletes preparing for 2027 races, and publishing what happens, including the parts that don't work. Join the launch list if you want to be considered.
Race-specific, week-by-week, fully aligned to your training.
Launching for the 2027 season. Everyone on the launch list gets a discount when we go live.
Two emails before launch. One when we go live. That's it.
Scope and safety
TrainedGut is a sports nutrition training protocol. It is not medical advice and it is not designed to diagnose or treat any condition.
Persistent or severe gastrointestinal symptoms deserve a doctor, not a training plan. If symptoms continue outside exercise, involve blood, or are getting worse, see one.
If you have a diagnosed gastrointestinal condition, are pregnant, or manage diabetes or another condition affected by carbohydrate intake, talk to a medical professional before starting.
Progressive carbohydrate loading is well tolerated in the published research, but individual response varies. Nothing here is a guarantee of performance.