December 17, 2025
Intra-workout fueling is mainly about sustaining carbohydrate delivery, managing hydration, and replacing sodium to maintain pace and reduce gastrointestinal (GI) issues. This guide shows what to eat and drink during long sessions, with clear targets based on duration, intensity, and sweat rate.
For sessions over ~75–90 minutes, aim for 30–60 g carbs/hour; for very long or hard sessions, build toward 60–90 g/hour (and up to ~120 g/hour only if well-trained).
Hydration is performance-critical: use sweat rate to guide fluid intake (often ~400–800 ml/hour, adjusted for conditions and body size).
Sodium reduces dehydration risk and supports fluid absorption; many athletes do well around 300–600 mg sodium/hour, more for salty sweaters or hot conditions.
Choose fuel formats that match intensity: liquids/gels for high intensity, solids for lower intensity or very long sessions.
Practice fueling in training and use “train the gut” progression to reduce GI distress on race day.
This is a practical “what to use when” list, ranked by how reliably each option delivers carbohydrates, fluids, and electrolytes with low GI risk during endurance sessions. Ranking favors options that: (1) hit carbohydrate targets efficiently, (2) support hydration and sodium replacement, (3) are easy to dose per hour, (4) are portable and stable, and (5) have a strong track record in racing and long training.
Once glycogen drops and dehydration rises, pace and power fall, perceived effort climbs, and GI problems become more likely. A simple intra-workout plan can improve performance, consistency in training, and recovery quality—especially when sessions exceed 90 minutes or occur in heat.
Combines carbs + fluids + sodium in one system, making hourly targets easier to hit with fewer moving parts. Liquid carbs tend to digest well at moderate-to-high intensity and reduce chewing/handling, which lowers GI risk and improves consistency.
Great for
Gels deliver precise, compact carbohydrate doses that are easy to scale to 60–90 g/hour without carrying bulky foods. When paired with adequate water (and sodium as needed), they support strong performance with predictable digestion.
The highest-ranked options solve the main problem of endurance fueling: delivering enough carbohydrate per hour without overwhelming the gut. Liquids and gels win because they’re easy to dose, swallow, and scale up when intensity rises.
Hydration and sodium are the silent multipliers. Many “bonks” are a combination of under-fueling and under-drinking (or drinking plain water without enough sodium), which can worsen GI symptoms and make it harder to take in carbs later.
Fuel format should match intensity: as breathing rate climbs, chewing gets harder and GI tolerance narrows—so shifting toward liquids/gels later in a session is often the simplest performance upgrade.
Often optional if well-fed beforehand, but a small amount of carbs can maintain quality, especially for higher intensity.
Great for
Most athletes benefit from planned fueling and hydration. This is the range where “I felt fine until suddenly I didn’t” is common without carbs.
Great for
Prioritize fast, low-chew fuels and avoid high fiber/fat. Keep intake frequent and steady to reduce gut load.
Great for
Mix formats to reduce flavor fatigue while still meeting targets. Chews or bananas can work well here.
Great for
Frequently Asked Questions
Use sweat rate: weigh yourself before and after a 60-minute session (same clothing, account for fluid consumed). The weight change (kg) roughly equals liters lost. Aim to replace a meaningful portion without trying to hit 100%—many athletes land around 400–800 ml/hour, adjusted for heat, pace, and stomach comfort.
Common triggers are too much carbohydrate too fast, overly concentrated drinks without enough water, high fiber/fat foods, and drinking large volumes at once. Reduce risk by starting fueling early, taking smaller doses more frequently, keeping drink concentration moderate, and practicing your exact race plan in training.
For shorter or cooler sessions, water may be enough. For longer sessions, heavy sweating, or heat, sodium helps maintain fluid balance and improves absorption. Many athletes do well around 300–600 mg sodium/hour, while salty sweaters may need more. The goal is steady performance and normal thirst—not perfectly replacing every milligram lost.
Often yes, if you’re targeting 60–90 g/hour or more. Multiple transportable carbohydrates can increase absorption and reduce the chance that one pathway gets overloaded. The key is gradual progression in training, not jumping to high intakes suddenly.
Add structure: start carbs within the first 20 minutes, then take a consistent dose every 15–20 minutes. Pair every gel/chew dose with water, and include sodium if you sweat heavily or train in heat. Consistency usually beats a “big hit” of fuel later.
Effective intra-workout fueling is a repeatable system: steady carbohydrates, enough fluids, and the right sodium for your sweat losses. Start with a simple plan (sports drink or gel + water), practice it in training, and adjust using real feedback from performance and stomach comfort. When long sessions feel smoother and pacing stays stable, you’ve found your baseline.
Track meals via photos, get adaptive workouts, and act on smart nudges personalised for your goals.
AI meal logging with photo and voice
Adaptive workouts that respond to your progress
Insights, nudges, and weekly reviews on autopilot
Great for
Chews are easy to portion and often include some sodium, but they require more chewing and can be harder to swallow at high ventilation rates. They are still a dependable way to hit carbohydrate targets when intensity is manageable.
Great for
A well-designed homemade mix can match high-end sports products and make 60–90 g/hour (or more) realistic. It ranks below commercial mixes mainly because mixing errors and concentration mistakes can increase GI risk.
Great for
Bananas are widely tolerated and provide carbohydrate plus some potassium, but they’re bulkier, less carb-dense than gels/drinks, and can be awkward at race intensity. Still, they’re a very practical whole-food option for many athletes.
Great for
These foods can be comforting, reduce flavor fatigue, and are easy to source, but they vary in carb content, are less convenient to dose precisely, and may be harder to eat during high intensity or on technical terrain.
Great for
Caffeine can improve alertness and performance, but dosing errors can increase jitters, gut upset, and sleep disruption. It ranks lower because it’s not a core fuel by itself; it’s a targeted performance tool layered onto carbs/hydration.
Great for
Carb delivery becomes a limiting factor. GI training, mixed carb sources, and disciplined pacing of intake are key.
Great for
Whole-food options become more viable. Keep fiber and fat modest and don’t let “easy pace” lead to accidental under-fueling.
Great for
