If you've ever typed "how to carb load" into a search bar the week before a race or meet, you've probably landed on a calculator that spits out a single scary number — "eat 800 grams of carbs" — with zero explanation of how, when, or whether your body can even handle that. That's exactly the problem Rob Polenik unpacks in this episode of the C3 Method Podcast, after a client with 10+ marathons under her belt PR'd her half marathon by several minutes almost entirely because she finally dialed in her nutrition.
Rob isn't guessing here. With a Master's in Human Nutrition, ACSM personal training certification, a NASM Corrective Exercise Specialist credential, and over 3,000 clients coached across 25 years — including competitive powerlifters, strongman athletes, and endurance runners — he's seen what actually works when the pressure is on and a generic calculator falls apart. In this post, you'll learn how carb loading differs between endurance and strength sports, how to figure out your real carbohydrate needs instead of relying on a plug-and-chug formula, and exactly how to time your protein, carbs, and fats in the days and hours leading into competition.
By the end, you'll have a practical framework you can start testing in your own training — not just a number to blindly follow.
The calculator Rob's client sent him asked for gender, age, height, weight, and event distance — then produced a flat carbohydrate target. Sounds personalized, right? It's not. It completely ignored what you're currently eating, how your body handles digestion under stress, your training history, and — critically — whether you're doing an endurance event or a strength event.
That last point matters more than almost anything else. An endurance athlete running a half marathon or marathon is producing a slow, steady energy demand over an hour or more. A powerlifter or strongman competitor experiences the opposite: short, explosive bursts of effort separated by long lulls of an hour or two between squats, bench, and deadlift, or between strongman events.
Those two energy demand curves require completely different carb loading strategies. Endurance athletes need calorically dense, highly digestible carbs they can consume in small volumes while moving, without triggering GI distress. Strength athletes have the luxury of longer rest windows between efforts, giving them more comfort and more opportunity to refeed glycogen between attempts — but they still need to manage nerves, appetite, and digestion so they don't feel flat or sluggish walking onto the platform.
A number generated from a formula that ignores all of this isn't personalized — it's a guess dressed up as science.
If you're training for a half marathon, marathon, or any prolonged steady-state event, your carb loading strategy needs to prioritize digestibility and caloric density over volume. You won't be able to eat large meals mid-race, so you need your body trained to tolerate gels, sports drinks, or simple carbs like graham crackers, animal crackers, or cereal — tested extensively in training, never for the first time on race day.
If you compete in powerlifting or strongman, your nutrition needs to match your event's rhythm: warm up, hit your attempt, then sit for 60–120 minutes before the next lift. Those lulls are your window to refeed. Rob's own competition experience is a great example — he gets so amped up before squats and deadlifts that his body "goes numb" and he has to consciously remind himself to eat. Some athletes are the opposite: nervous energy suppresses their appetite entirely. Either way, you need to know your own pattern before competition day, not during it.
Before you even think about carb loading, Rob starts every client at the same place: what are you eating right now, going into this? Most endurance athletes he works with chronically undereat carbohydrates and protein, have inconsistent fat intake, and — most importantly — mistime their carbs, eating too little around training and too much away from it. That combination produces the "skinny-fat" look, nagging injuries, and stalled performance.
Here's the baseline framework Rob recommends:
Once your totals are set, distribute them across three 5-to-6-hour windows in your day. Start by splitting calories and protein evenly across all three (roughly a third each). Once that feels normal, shift your carbs and fats — not protein — to favor the window around your training. A morning athlete might eat 40% of daily carbs/fats before training, 40% in the midday window, and only 20% in the evening. An evening athlete flips that ratio.
This is where Rob's protocol gets specific. The day before your event, when you're intentionally minimizing activity:
If your event is in the morning, you can load the bulk of your carbohydrates the night before, since glycogen storage happens overnight. If your event is in the evening, you don't need the "sleep empty, wake up empty" strategy — instead, taper carbs down throughout the day so you arrive at your event window with glycogen intact.
On the morning of the event, stick close to what you've already practiced and tolerated well in training. If your stomach allows it, add a small amount more. If nerves make solid food impossible, sip sugary fluids like Gatorade or fruit juice (though fructose can upset some stomachs) to get in hydration and quick carbs.
During the event itself, there's no universal number. Rob has coached athletes who thrive sipping only water through a marathon, and others who consume gels regularly with zero GI issues. Powerlifters he's trained have fueled successfully on everything from bagels and jelly to muffins and cookies between attempts. The individual variance is enormous — which is exactly why testing this in training, not on competition day, is non-negotiable.
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Q: How many carbs should I eat when carb loading for a marathon?
There's no single universal number — it depends on your current intake, body size, and digestive tolerance, not just a calculator based on age and event distance. Rob's approach is to gradually shift your protein down and carbs up the day before the event, based on what you've already practiced and tolerated in training, rather than aiming for a fixed gram target like 800g.
Q: Should I carb load differently for strength sports than for running?
Yes, significantly. Endurance athletes need small-volume, highly digestible carbs they can consume while moving over a sustained effort, while strength athletes have longer rest windows between attempts that allow for more substantial refeeding between lifts or events.
Q: When should I start carb loading before a race?
Start practicing your fueling strategy weeks or months before the event during training, then intentionally increase carbohydrates the day before competition by cutting protein roughly in half and reallocating those calories to carbs, spread evenly throughout that day.
Q: What should I eat the morning of a competition?
Stick to the carbohydrate amount and food types you've already practiced and tolerated well in training. If you're too nervous to eat solid food, sugary fluids like Gatorade or fruit juice can provide quick carbs and hydration without overwhelming your stomach.
Q: Is it bad to train on an empty stomach before a run?
It's not ideal for performance, but it's a habit that can be improved gradually — Rob recommends starting with something as small as a 100-calorie pack of M&M's before training and slowly building tolerance from there rather than forcing a big change all at once.
Carb loading for peak performance isn't a single formula you plug your stats into — it's a personalized system built on your current eating habits, your sport's energy demand curve, your digestive tolerance, and your emotional response to competition. Whether you're chasing a marathon PR or a new deadlift max, the athletes who perform best are the ones who've tested their fueling strategy in training long before it matters, so nothing on event day is a surprise.
Start with the basics — dial in your calories, hit 0.8g of protein per pound of bodyweight, and distribute your carbs and fats around your training windows. Then experiment with the day-before carb load protocol and see how your body responds. The complexity resolves into clarity once you actually put it into practice.
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Want to hear Rob break down the full carb loading protocol in his own words, including his personal experience fueling for 600+ pound deadlifts on pure adrenaline? Tune in to the full episode: 2334 - How to Carb Load for Peak Performance.