Simplifying Triathlon Nutrition: The Myths and Realities
Most triathlon nutrition advice is aimed at athletes whose performance is limited by metabolic efficiency and race-day fuelling precision. Most age-group triathletes are limited by something considerably more basic: under-fuelling during training, inadequate carbohydrate in races, and GI problems caused by products that were never properly tested. The gap between what the nutrition industry markets and what actually needs solving is large, and crossing it requires less sophistication than most athletes assume.
01 | Daily Nutrition: The Foundation
Race nutrition gets the attention. Daily nutrition does the work.
An athlete arriving at sessions consistently under-fuelled adapts more slowly, recovers less completely between sessions, and accumulates fatigue that eventually reads as stagnation or injury. The mechanism is direct: training creates demand for energy and substrate that the body uses during recovery to produce adaptation. If supply does not meet demand, the adaptation is incomplete. No race-day strategy compensates for months of inadequate daily fuelling.
The most common daily nutrition mistake among time-crunched athletes is treating training days like rest days. Eating a normal work lunch, completing a 90-minute evening session in a depleted state, eating dinner, and expecting adequate overnight recovery. This works up to a point. As training load increases the deficit compounds, and fatigue starts to look like fitness plateauing when it is actually a fuelling problem.
Carbohydrate is the primary fuel for any training intensity that matters for triathlon performance. Arguments for training in a depleted state to improve fat oxidation have a limited evidence base and are largely irrelevant for athletes whose constraint is fitness and consistency rather than metabolic efficiency at the margins. Keeping carbohydrate intake adequate across training days, especially around sessions, is the most reliably effective nutritional intervention available and requires no products or protocols beyond normal food.
Protein requirements for endurance athletes sit at roughly 1.4 to 2.0 grams per kilogram of body weight per day, towards the upper end during high training loads or blocks involving strength work. Twenty to 40 grams consumed in the period after training supports muscle repair effectively. Greek yogurt and quark are among the most practical sources: 10 to 15 grams of protein per 100 grams, widely available, and accompanied by nutrients that processed powders do not carry. Protein powder is not harmful. It is also not necessary for athletes eating a varied diet. It is a solution to a problem most triathletes do not have. The full picture on daily training nutrition — including pre-session fuelling, session-to-session recovery, and how nutrition integrates with training load — is covered in the article on training nutrition and cutting through the noise.
02 | How Carbohydrate Works During Racing
The recommended carbohydrate intake per hour during racing has been moving upward for twenty years. Sixty grams per hour was the established standard for most of the 2000s. Ninety grams became common through the 2010s. Professional athletes are now publishing protocols at 120 grams per hour and above. The numbers keep moving because gut training research has advanced, but the underlying physiology has not changed, and understanding it makes the debate considerably easier to navigate.
Glucose is absorbed from the small intestine via a transporter called SGLT1, which saturates at approximately 60 grams per hour. Consuming more glucose than this does not accelerate delivery to the muscles. It accumulates in the gut and becomes a GI problem. Fructose uses a different transporter, GLUT5, which operates in parallel. Combining glucose and fructose in a ratio of roughly 2:1 allows total carbohydrate absorption to reach approximately 90 grams per hour without SGLT1 becoming the limiting factor, because both transporters are running simultaneously rather than one doing all the work.
The 120 gram protocols require the gut to be specifically trained over months to handle high-volume carbohydrate intake. The professional athletes running these protocols are not simply consuming more gels. They are completing structured gut training programmes using concentrated glucose-fructose mixes at specific ratios, consumed consistently during long sessions across an extended preparation period. The performance benefit exists, but it is contingent on adaptations that take months to develop deliberately and that most age-group athletes have not undertaken.
For most triathletes the practical target is 60 to 90 grams of carbohydrate per hour, consumed consistently across the bike and run. The lower figure is achievable without any specific gut preparation. The upper figure requires systematic gut training across a season but is realistic for an athlete who commits to practising their race nutrition in training. At 70 kilograms of body weight, one gram per kilogram per hour sits comfortably in the useful range. A planning conversion worth remembering: 60 grams of carbohydrate per hour equals approximately 240 calories.
03 | Race Fuelling in Practice
Timing matters more than total quantity in any given window. Small, regular intake throughout the bike and run is more effective than infrequent large boluses. The gut handles continuous low-level delivery better than sporadic large doses, and consistent fuelling prevents the energy dips that come from gaps in the fuel window. The approach I use with athletes is something every 15 minutes on the bike, adjusted for conditions and race duration. The discipline of sticking to that schedule, even in the early stages when appetite is low and pace feels easy, is where races are either insured or quietly compromised.
The transition to the run requires specific attention. Gastric emptying slows as run intensity increases, which means GI tolerance on the run is generally lower than on the bike. Products that work perfectly at threshold power on the bike can become unmanageable once running pace and diaphragm mechanics change the equation. Liquid and semi-liquid sources tolerate better. The aid station cola that features in many experienced athletes' run strategies has a practical logic: glucose and fructose together, caffeine, and a flavour profile that works when sweet gels have stopped working, in a format the gut handles reliably under race conditions.
Full distance racing adds a variable that 70.3 racing largely avoids: flavour fatigue. An athlete on the course for ten to twelve hours will find that products palatable at hour two become difficult by hour eight. Planning a second flavour, or a transition from sweet to savoury, into the race nutrition structure for full distance is worth doing during training, not discovering mid-race.
When I prepared for my full distance race working with Brett Sutton, the plan he gave me was as far from a premium nutrition protocol as it is possible to get. Gatorade Fruit Punch. The cheapest chocolate bars I could find in the supermarket. Water. Coca-Cola on the run. The schedule was a quarter bottle of Gatorade alternated with a third of a chocolate bar and a third of a water bottle every 15 minutes on the bike. On the run, a 50/50 mix of water and Coca-Cola from the aid stations.
The logic behind it holds up under scrutiny. Gatorade delivers glucose and fructose in a well-tested ratio with basic electrolytes, in a format the gut handles reliably because it has been handling it at low osmolality for decades. The chocolate provides mixed carbohydrate with some fat, which changes the palatability profile, slows the delivery slightly, and maintains caloric density without relying entirely on liquid sources. Coca-Cola on the run delivers glucose, fructose, and caffeine at a point in the race when both the palatability and the stimulant effect have clear value. None of it required a sports nutrition company, a pre-race consultation, or a premium price. What it required was practising the schedule in training until execution was automatic.
04 | GI Problems and How to Avoid Them
Gastrointestinal problems during racing are among the most common performance-limiting issues in long-course triathlon. The large majority of them are preventable, and the causes are consistent enough that avoiding them is mostly a matter of preparation discipline.
The primary cause is products that have not been tested under race-comparable conditions in training. Nothing consumed in a race should be appearing for the first time on race day. This applies to gels, drinks, bars, and anything available at aid stations. Athletes who plan to use race-course nutrition need to know exactly what those products are and need to have tested them at training intensities that replicate race effort. Changing products close to a race, or leaving race nutrition to chance at aid stations, introduces GI risk that preparation can eliminate entirely.
Concentration is the second common cause. A 750-millilitre bottle containing 90 grams of carbohydrate is more concentrated than one containing 60 grams, and the gut's tolerance for osmolality decreases under race stress, heat, and fatigue. Athletes who experience GI problems on the bike are often not consuming too many carbohydrates in absolute terms but too high a concentration relative to their current absorption capacity. The fix is typically to dilute the drink and supplement with solid food rather than to reduce total intake, because total intake often does not need to drop, only the concentration per unit volume.
The gut adapts to carbohydrate consumption. Athletes who regularly fuel during long training sessions develop greater absorption capacity and tolerance than those who train fasted or with minimal nutrition. Gut training requires nothing more than treating long training sessions with the same nutrition approach planned for racing, consistently, across a block. The athletes who experience the least GI trouble in races are almost always those who have practised their race nutrition rather than deployed it for the first time on the day.
05 | Making It Cheaper Without Making It Worse
The practical case for simple, inexpensive race nutrition is not only financial. Simple products are easier to source, easier to test across different race environments, and introduce fewer variables on race day.
The homemade sports drink is the most direct expression of this. Forty grams of maltodextrin and 20 grams of fructose in 750 millilitres of water delivers approximately 60 grams of carbohydrate per bottle at a glucose-to-fructose ratio that supports good absorption. Adding a gram of table salt covers basic electrolyte replacement. The formulation is functionally identical to what most mid-tier gel and drink brands are selling in premium packaging, and the ingredients cost a fraction of the retail price. The main variable worth testing individually is fructose quantity: some athletes tolerate the full 20 grams without issue, others do better at 10 to 15 grams. Adjusting the recipe costs nothing; adjusting which commercial product to use still costs full retail price each time.
For athletes who prefer commercial products for convenience or palatability, the decision criteria should be GI tolerance, carbohydrate content, and how the flavour holds through the final hours of the race. Products at different price points containing the same glucose-fructose ratio will perform identically in the gut. The premium version is paying for branding and packaging, not a different nutritional outcome. The broader context on how sports nutrition products are manufactured and marketed is covered in the article on fads in triathlon. The practical decision is simpler than the market would have you believe: test it in training, find what you tolerate, and practise it until execution is automatic. Those three steps determine race nutrition success more reliably than anything the industry sells.
Race nutrition is one of those areas where complexity often disguises a lack of preparation rather than a depth of knowledge. The athletes who execute it best have usually committed to a simple plan and practised it consistently, not optimised an elaborate protocol. If you want to work with a coach who builds race nutrition into preparation from the start, with the planning already done rather than left to race week, Sense Endurance Coaching is where to begin.
If you are preparing from a training plan, the structure and pacing of race nutrition can still be trained systematically. My plans are built with fuelling practice integrated into the long sessions rather than treated as a separate problem. You can find the full range on the training plans page. The best race nutrition plan is the one that has been tested enough to be boring by the time race day arrives.