Nutrition: Endurance vs. Interval Fueling the Different Demands of Cycling

Words and Photography by James Ion

In this journey back to fitness, I’m looking at all aspects of nutrition—how and when to fuel, what to eat, and different sources of energy. It always seems complicated, but in reality, it’s quite simple. We all know what’s “good” for us—or better for us—because in a pinch, even Haribo is “good” when you’re out on the bike.

But with so much information out there, it gets confusing. Factor in things like nutrient timing, intermittent fasting, ketosis, reprogramming your gut biome, and chronobiotic eating, and suddenly you have no idea what’s good anymore!

Well, ladies and gentlemen, never fear—because as your faithful guinea pig, I’m here to help clear the fog and delete the nonsense. Fueling your rides shouldn’t be complicated. You just need to follow a few rules.

This month, I’m breaking down the fueling needs and strategies for different types of rides. And before any low-carb fanboys chime in: this blog promotes carbs. We love them. Carbs are king, no matter what you’re doing. It’s also important to note that the carbs I discuss here are in addition to your baseline daily calorie needs—these are the extra calories required for training.

Endurance Ride Nutrition: The Long and Steady

Endurance rides are the bread and butter of cycling—long hours, mostly in Zone 2, building the aerobic engine. They don’t feel particularly demanding in the moment, but the fatigue creeps in if you don’t fuel properly.

This is the type of ride where you can mix sports products and real food—both work well. With lower intensity, you don’t need sugar to hit your system instantly. Foods like bananas (about 27g carbs) work great. The problem is scale: if you need ~60g carbs per hour, that’s two bananas every hour, or eight bananas on a 4-hour ride. You’ll need big pockets!

What works best for me is a combo: first hour = 10 dates and a banana, then chews or bars for the rest.

Carbs are carbs—you don’t need fancy sports nutrition products. Haribo is actually great. Our nutrition expert Kate Macleod swears by them, and she has a six-pack year-round, so it must be fine.

Sports scientist Chris Harris of Precision Fuel & Hydration suggests a steady drip-feed of carbs—30–60g/hr. For a 3–4 hour ride, he also recommends leaning on real food: bananas, bars, rice cakes. The key is avoiding flavour fatigue—there’s only so much syrupy gel you can stomach before you start dreaming of bread and cheese.

Example: 4-Hour Endurance Ride

• Pre-ride: Oats with fruit and honey (~80g carbs)

• On-bike: 1 banana, 10 dates, 6 PF&H 30g carb chews (~60g carbs/hr)

• Hydration: 500ml PF&H electrolyte drink per hour (adjust for sweat rate)

That’s ~240g carbs total—enough to keep the legs ticking without feeling like a science experiment.

Tempo Intervals: The Sweet Spot Grind

Tempo training is where fueling starts to look like racing. You’re not emptying the tank like in VO₂ max work, but you’re burning glycogen much faster than at endurance pace. Chris suggests 75–90g/hr here—basically race-day practice.

Think of it as training your gut as much as your legs. If you want to take in 80g/hr on race day, you need to get comfortable with that in training. Sports nutrition is best here—quick-absorbing carbs to get your gut primed. Gels, chews, and drink mixes all work well: fast, predictable energy that doesn’t fight back.

Example: 90-Minute Tempo Ride

• Pre-ride: Carb-rich breakfast (toast with jam, banana, coffee, ~100g carbs)

• On-bike: 2 PF&H gels + 1 packet PF&H chews (~120g carbs total, 80g/hr)

• Hydration: 1 bottle PF&H 1000 electrolyte mix

You’ll finish trained, not trashed.

Intervals: VO₂ Max, 5x5s, and the Pain Cave

If endurance rides are patience, intervals are survival. High intensity is powered by glycogen, and Chris is blunt: glycogen is king.

A carb-rich pre-ride meal is non-negotiable. During the session, gut tolerance drops because blood flow shifts to working muscles. That’s why gels and drink mixes are best—fast, low-effort to digest. Sometimes, it’s not about fueling mid-interval, but topping up in warm-up or between sets.

Example: 5x5 Min VO₂ Max (90 min total)

• Pre-ride: Big carb meal 2–3 hours before (rice, eggs, fruit, ~120g carbs)

• On-bike: 1 PF&H gel in warm-up, 1 during rest intervals (~60g carbs total)

• Hydration: 1 bottle PF&H 1500 electrolyte mix (offset sweat loss)

You won’t want to chew when your heart rate’s maxed—this is about supporting the session without upsetting your stomach.

Mixed Sessions: When Steady Meets Spiky

Some days you’ll do long endurance with sprints sprinkled in. The rule: fuel steadily during the base, with a small bump before efforts. Chris notes a “burn overshoot” after intervals—so don’t stop fueling when the hard part ends. Keep the drip-feed running.

Fasted Training: Just Don’t Bother

There was a time when fasted training was “de rigueur.” Everyone thought it turned them into fat-burning machines. Reality check: it doesn’t work that way.

Yes, it can nudge fat adaptation. But it reduces session quality and recovery. You’re essentially compromising two days of training for a tiny metabolic gain. Carbs are king, and once intensity rises, you’re burning carbs anyway.

Chris’s advice: skip it. A smarter alternative is lighter fueling on easy days, not no fueling. Endurance gains come from quality, carb-fueled sessions that let you push harder, adapt, and recover better.

Hydration: The Forgotten Side of Fueling

Hydration is often the most overlooked factor. Yet it can be the difference between hitting targets and failing miserably.

Once you feel thirsty, it’s too late. Aim for ~2L water daily, and drink regularly during rides. Chris’s approach is more precise: weigh yourself before and after a ride (clothes on, bottles and food in hand) to estimate sweat rate. Aim to limit fluid loss to 2–4% of body weight.

For hot, hard sessions, that means more fluid and sodium; for cool endurance days, much less. “More” isn’t always better.

That’s where PF&H mixes help:

• 1000mg sodium for steady rides

• 1500mg sodium on hot or intense days

Wrapping It Up

The lesson: not all rides are created equal, and neither should your fueling.

• Endurance: slow and steady, real food in the mix.

• Tempo: gut training with higher carb loads.

• VO₂ max: go in fueled, top up with gels.

• Hydration: tailored, not random.

When fueling is wrong, the ride falls apart. When it’s right, 4 hours feels fun, intervals feel (almost) manageable, and recovery is faster.

Fuel isn’t just energy—it’s a training tool. Learning how to use it is as important as the training itself.

If you want to dial in your own strategy, check out the free fueling planner from Precision Fuel & Hydration here