Beyond the Basics: Advanced Fueling Tools for Endurance Athletes
Most endurance athletes have not yet optimized the fundamentals — carbohydrate loading, gut training, dual-transporter products, sodium management, and caffeine timing. These basics produce the largest performance gains and should be the priority for any athlete who has not yet mastered them.
But for athletes who have the fundamentals in place and are looking for additional marginal gains, three advanced fueling tools have meaningful research support: sodium bicarbonate, ketone esters, and hydrogel carbohydrate products. The ANC framework treats these as athlete-specific, optional protocols — not defaults — because each requires individual testing, carries real risks, and is appropriate only for specific athletes in specific situations.
This article covers what the current evidence actually shows for each, who they are for, and how the ANC framework uses them.
Sodium Bicarbonate (Buffering Aid)
What It Is
Sodium bicarbonate — baking soda — is an alkalizing agent that buffers the accumulation of hydrogen ions produced during high-intensity exercise. As exercise intensity rises above Critical Power or Critical Speed, anaerobic metabolism produces hydrogen ions that lower muscle pH and contribute to fatigue. Sodium bicarbonate raises blood pH before exercise, creating a larger buffer capacity and delaying the onset of acidosis-related fatigue.
What the Research Shows
The evidence for sodium bicarbonate as a performance enhancer in high-intensity endurance events is reasonably well established. It is most effective for events with a significant high-intensity component — where athletes are spending meaningful time above their Critical Power or Critical Speed threshold. The performance benefit is most consistent in shorter, higher-intensity events and in the high-intensity portions of longer events.
Who It Is For
The ANC framework considers sodium bicarbonate most useful for:
- Olympic-distance triathlon and sprint triathlon, where race intensity is consistently high
- The bike portion of IRONMAN 70.3 racing, where athletes can sustain near-threshold effort
- Athletes who have confirmed through testing that they can tolerate it without GI distress
Sodium bicarbonate is not appropriate for athletes who have not tested it extensively in training. GI distress — nausea, cramping, diarrhea — is a real and common side effect, particularly with standard powder or tablet forms. Slow-release formulations (such as the Maurten Bicarb System or MNSTRY) reduce but do not eliminate this risk.
Protocol
The ANC framework uses a dose of 0.2–0.4 g per kg of body weight, taken 60–180 minutes before the start in slow-release tablet form. The wide timing window reflects individual variation in absorption rate. Athletes must determine their personal optimal timing through repeated testing in training — not on race day.
This protocol requires extensive trialing before race day. Do not attempt sodium bicarbonate for the first time in competition.
Ketone Esters
What They Are
Ketone esters are synthetic compounds that raise blood ketone levels rapidly without requiring dietary carbohydrate restriction. The hypothesis is that providing an additional fuel substrate alongside carbohydrate could spare glycogen, reduce lactate accumulation, and improve endurance performance.
What the Research Shows
The evidence for ketone esters in endurance performance is currently limited and mixed. Early research generated significant interest, but subsequent studies have not consistently replicated meaningful performance benefits when ketone esters are used alone. The most promising current hypothesis is that ketone esters may provide benefit when co-ingested with sodium bicarbonate — because ketones are acidic and may cause acidosis that bicarbonate can buffer, potentially allowing both compounds to work more effectively together.
The ANC framework reflects the current state of the evidence: ketone esters are not recommended as a standalone intervention for most athletes. They are expensive, unpalatable, and the performance benefit without bicarbonate co-ingestion is not well established. Athletes who are interested in ketone esters should do so only with specific coaching guidance and a clear testing protocol.
Who They Are For
Ketone esters may be worth exploring for elite athletes who have fully optimized all other fueling variables and are looking for additional marginal gains in high-stakes competition. They are not appropriate for most age-group athletes, first-timers, or athletes who have not yet mastered the fundamentals.
Hydrogel Carbohydrate Products
What They Are
Hydrogel products — most notably the Maurten line — use a pectin and alginate matrix that forms a gel in the acidic environment of the stomach. The proposed mechanism is that this gel structure slows gastric emptying in a controlled way, reducing the osmolality spike that causes GI distress with high carbohydrate concentrations and potentially improving absorption consistency.
What the Research Shows
The evidence for hydrogel products is mixed. Current research does not consistently show that hydrogel products outperform standard dual-transporter products (maltodextrin + fructose at equivalent carbohydrate doses) in terms of performance or absorption rate. The proposed GI distress reduction benefit has some support but is not universal across athletes.
The practical conclusion from the ANC framework: hydrogel products do not appear to provide a meaningful advantage over well-formulated standard dual-transporter products for most athletes. However, they may reduce GI distress for athletes who struggle with high carbohydrate intake using standard products — making them a reasonable option to trial for athletes experiencing GI issues at 90+ grams of carbohydrate per hour despite gut training.
Who They Are For
The ANC framework considers hydrogel products worth trialing for:
- Athletes who experience persistent GI distress at high carbohydrate intake despite gut training and correct product selection
- Athletes who have confirmed that standard dual-transporter products cause GI issues at their target intake rate
Hydrogel products are not necessary for athletes who tolerate standard dual-transporter products well. The premium price is not justified by performance benefits alone — only by GI tolerance benefits for athletes who need them.
The ANC Approach to Advanced Protocols
The ANC framework treats all three of these protocols as athlete-specific options, not defaults. They are flagged in the Race Day Fuel Planner for athletes who specifically ask about them, with current evidence summaries and appropriate cautions.
The governing principle: advanced protocols are only worth pursuing after the fundamentals are fully optimized. An athlete who has not yet mastered gut training, dual-transporter product selection, sodium management, and caffeine timing will gain far more from fixing those fundamentals than from adding sodium bicarbonate or ketone esters on top of a poorly executed base plan.
For athletes who want to explore advanced protocols with proper coaching support, ECHO 1:1 Comprehensive Coaching includes individualized fueling protocol development as part of the complete race preparation process.
Frequently Asked Questions
Should I try sodium bicarbonate for my next IRONMAN?
Only if you have tested it extensively in training and confirmed you can tolerate it without GI distress. The GI risk is real and race-ending. If you have not tested it, do not use it on race day.
Are ketone esters worth the cost?
For most age-group athletes, no. The evidence for standalone performance benefit is not strong enough to justify the cost and palatability challenges. If you are interested, discuss with your coach and establish a proper testing protocol before committing to race-day use.
Is Maurten better than other gels?
Not necessarily for performance. Maurten products are well-formulated dual-transporter products with a hydrogel delivery system. They may reduce GI distress for athletes who struggle with standard products at high carbohydrate intake. For athletes who tolerate standard dual-transporter products well, the performance benefit over equivalent products is not established.
How do I know if I have optimized my fueling fundamentals?
You have completed at least three full practice runs of your race-day fueling plan. You are using dual-transporter products. You have established your sweat rate and sodium targets. You have a caffeine protocol you have practiced. You are hitting your carbohydrate targets consistently in training without GI distress. If any of these are not in place, start there before exploring advanced protocols.
Related: Race Day Fuel Planner ($49) · What is Gut Training? · Caffeine for Endurance Athletes · Sodium and Electrolytes Guide · ECHO 1:1 Comprehensive Coaching