How to Fuel a Century Ride — The 100-Mile Nutrition Plan

What to eat during a 100-mile bike ride has turned into a moving target with all the sponsored content, conflicting advice, and Instagram athletes noise flying around. As someone who bonked catastrophically at mile 67 of my first century — legs completely gone, vision doing something strange, sitting on a guardrail eating a stranger’s spare Clif Bar with absolutely zero shame — I got hands-on with endurance nutrition the brutal way. Fourteen centuries later, plus a consultation with an actual registered sports dietitian and an embarrassing number of evenings reading carbohydrate metabolism research, this is the plan I personally use. No sponsorships. No agenda.

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The Numbers — How Many Carbs Per Hour

Start here. Two numbers run everything: 60 to 90 grams of carbohydrates per hour, and 200 to 300 calories per hour. Write them on your hand if that’s what it takes.

But what is the 60g lower bound, exactly? In essence, it’s the ceiling for single-source carbohydrate absorption — glucose or maltodextrin alone. But it’s much more than that. The 90g upper range only becomes reachable when you’re pairing glucose with fructose, which use entirely separate intestinal transport pathways — meaning your gut can process both at the same time. That’s why most sports drinks and gels are built around a 2:1 glucose-to-fructose ratio. Something like a Maurten Gel 100 delivers 25g of carbs per sachet. At the high end, you’d need three of those every hour. Gets expensive. Gets repetitive. Gets old around mile 55.

The calorie numbers look low — a 160-pound rider at moderate century pace burns roughly 500 to 600 calories per hour. You’re not replacing that. You’re not supposed to. The actual goal is sparing glycogen and keeping blood glucose from sliding, not hitting caloric neutrality. Accepting that gap matters. Trying to eat 500 calories an hour is a gastrointestinal disaster with a very predictable ending.

One more thing. Start fueling at the 30-minute mark — not when you feel hungry. Hunger during exercise is a lagging indicator. By the time your brain sends the signal, your glycogen is already dropping. Set a timer. Eat before you want to.

Hour-by-Hour Nutrition Plan for 100 Miles

Here’s the part worth saying first. It’s what most people actually scrolled here for. Here’s how to structure nutrition across a full century, assuming roughly 15 to 17 mph and six to seven hours total riding time.

Pre-Ride — Three Hours Before the Start

Eat a real meal. My standard is oatmeal with a sliced banana, one tablespoon of peanut butter, and 16 ounces of water with a single Nuun Sport tablet dissolved in it — roughly 500 to 600 calories, mostly complex carbs, small amounts of fat and protein to slow digestion. Nothing experimental. Nothing that hasn’t been tested on a long training ride first.

Frustrated by a spectacularly bad pre-ride decision at the 2021 Gravel Grovel in Ohio, where I ate an entire breakfast burrito ninety minutes before the start gun and spent two hours in genuine gastrointestinal misery, I now refuse anything substantial within two hours of a ride. Don’t repeat what I did. Give your body actual time to digest what you put in it.

Hours One and Two — Light and Consistent

Glycogen stores are full. Legs feel good. This is precisely when riders eat nothing — because they feel fine and don’t think they need to yet. Eat anyway. Target the lower end of the range, around 60g carbs per hour, and keep it boring. One banana, one rice cake, or two Medjool dates every 45 minutes. Sip your first bottle steadily. Don’t get excited. The century is long and patience here pays off at mile 80.

Hours Three and Four — Increase Intake

This is where the real discipline lives. Stores are depleting, the psychological weight of “halfway done but still so far” settles in around mile 50, and — somewhat counterintuitively — digestion is actually more efficient now that you’ve been riding at a steady state for a while. Push toward 75 to 90g of carbs per hour. Add a gel or two alongside real food. Hit any SAG stop you encounter — refill bottles, grab something salty, take ninety seconds off the bike.

I carry a small insulated pouch — the Revelate Designs Mountain Feedbag, around $34 — stuffed into my jersey pocket. It holds two rice cakes and a gel without compressing everything into a warm, unidentifiable mass. That’s a detail that feels trivial at mile 10 and genuinely matters at mile 55.

Hours Five and Beyond — Whatever Your Stomach Tolerates

Honest answer: this is deeply personal. Some riders eat normally at mile 80. Others need to drop back to liquids only. Know which one you are before race day — not during it. What I can tell you from experience is that salty and savory foods become dramatically more appealing than sweet ones after five hours. A small peanut butter and honey sandwich on plain white bread — white specifically, not whole grain, because you need fast digestion at that point — is something I can actually eat at mile 85 when the sight of another gel wrapper makes me want to quit cycling forever.

Keep eating. Fatigue makes it feel optional. It isn’t.

Real Food vs Gels — What Works at Mile 75

Gels are engineered for convenience, not for enjoyment. They work well — genuinely well — for the first two or three hours. After that, something shifts. The texture becomes wrong. The sweetness becomes almost aggressive. You open a GU Salted Caramel at mile 78 and your body just sends back a flat refusal.

This is not weakness. This is completely normal.

Real food solves the psychological half of this problem. Rice cakes made with soy sauce, sesame oil, and a pinch of salt — a recipe that got popularized through the Rapha Continental riders and Allen Lim’s cookbook — are genuinely good to eat at mile 70. Banana halves wrapped in aluminum foil. Fig Newton cookies, which deliver about 11g of carbs each and cost roughly $4 per pack. Salted boiled baby potatoes in a small zip-lock bag — a trick borrowed from ultra-cycling circles that sounds completely unhinged until hour six, when they taste like the best thing you’ve ever put in your mouth.

The practical answer is to use both. Gels and chews during high-intensity efforts or technical descents where unwrapping a rice cake feels genuinely dangerous. Real food during climbs slow enough to eat safely, at aid stations, any time you have a moment to actually chew something.

A working split for a seven-hour century: four to five gels, two rice cakes, one banana, a small bag of dates or fig bars, plus whatever the event provides at aid stations. Don’t gamble entirely on aid stations — some are stocked beautifully, some have a bucket of warm orange slices and lukewarm water.

Hydration Strategy — More Than Just Water

One bottle per hour is the floor, not the target. Above 75°F, plan for 1.5 bottles per hour. A standard cycling bottle holds 21 to 24 ounces depending on the brand — I use Specialized Purist 22oz bottles specifically because they don’t hold flavor between rides. Riding at 15 mph in July heat, you can lose 32 ounces an hour through sweat without it feeling dramatic until suddenly it does.

Water alone won’t carry you through a century. Sweat takes sodium, potassium, magnesium, and chloride with it. Replace only the water and you dilute your blood sodium — that’s hyponatremia, and it produces headaches, nausea, confusion, and in serious cases, conditions that require actual medical attention. Electrolytes go in every bottle. Not most bottles. Every single one.

My setup is straightforward: one bottle with Skratch Labs Sport Hydration Mix — 80mg sodium per serving, about $22 for a 20-serving bag — and one bottle of plain water. The plain bottle handles face rinsing and the moments when flavored drink starts tasting oppressively sweet, which happens more than you’d expect.

Signs of Dehydration to Watch For

• Dark yellow urine at aid station stops — pale straw color is what you’re aiming for
• Headache appearing at the back of the skull specifically, not the front
• Muscle cramps in the calves or hamstrings
• Unusual irritability or genuine difficulty making simple decisions
• Reduced sweat rate despite hard effort — this one is alarming when it actually happens

Two or more of those simultaneously means you stop. Drink. Eat something salty. Give it ten minutes before pushing on. No finish-line time is worth a roadside medical situation.

One underrated move: start hydrating the night before. Drink an extra 16 to 20 ounces with dinner and keep a glass on your nightstand. Showing up to a start line already slightly dehydrated — easy to do when you’re nervous and distracted — puts you behind before the first pedal stroke.

That’s the whole plan, honestly. A century is a long day. The riders finishing strong aren’t always the most fit — they’re usually the ones who treated nutrition as seriously as any training block. Get the numbers right, start fueling at 30 minutes, rotate real food into the mix, and drink more than feels strictly necessary. The guardrail at mile 67 taught me all of this the hard way so you don’t have to learn it the same way I did.