When you can get a professional marathoner running 140 miles a week, a performance nutritionist who has spent twenty years in elite sport locker rooms, and a run coach who has worked with tens of thousands of recreational athletes in the same room in Boulder, you know it’s going to be a good one.

Charlie Sweeney, Dr. Marc Bubbs, and Jason Fitzgerald sat down to talk about the things most runners are still getting wrong. The conversation was practical, honest, and occasionally funny. There was pizza.

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It's not the shoes. It's not the training plan. It's not the recovery modality they haven't tried yet. According to all three panelists, the biggest thing holding most runners back is a lack of intentionality around fueling — specifically, a vague, figure-it-out-as-you-go approach to what they eat and drink on long runs and race day.

Jason has been coaching since 2010 and has watched the fueling conversation change dramatically in that time. He ran his marathon PR in 2011 on 48 grams of carbohydrate per hour and thought he was doing great. The conversation has shifted so much since then that what was considered aggressive fueling fifteen years ago is now considered a starting point for some athletes.

Dr. Bubbs frames it around what he calls the three Ts — total amount, timing, and type. Most runners don't have a number for any of the three. They don't know roughly how many grams of carbohydrate they're consuming on a long run. They don't know when they're taking it in relative to effort. They don't know whether they're choosing fast or slow carbs at the right moments. Getting a rough benchmark on all three is the single most impactful thing most runners can do.

What 700 grams of carbohydrate actually looks like

Charlie is running 140 miles a week across two sessions a day five days a week. His loose daily estimate for carbohydrate intake is 700 grams. When he floated that number in the room, it landed hard.

He didn't start there. In college he was doing 20-mile runs on water, taking a protein shake on the drive home, and napping for three hours every Sunday. He thought the exhaustion was normal. When he started experimenting with intra-run fueling — starting at just 40 grams of carbohydrate over two hours, which felt brutal at first — his runs got better and his Sundays came back. He could go out to dinner. He felt like a person.

Now he doesn't leave the house for anything over 90 minutes without fuel. He hit 110 grams of carbohydrate per hour at Boston this year, which was a personal record, and felt good enough afterward to go out with his family. That was also new.

The journey from no fuel to 110 grams an hour took years. That's the part people skip when they see the number and try to replicate it immediately.

Fast carbs versus slow carbs

Dr. Bubbs made a point that's worth sitting with. The word sugar carries a negative connotation for most people because in a non-athletic context, consuming too much of it leads to real health problems. But for athletes, thinking in terms of fast and slow carbs is more useful than thinking in terms of good and bad sugar.

Before training, during training, immediately after training — you want fast. You're trying to get fuel into the tissue as quickly as possible. Away from exercise, you want slow. Complex carbs, steady energy, nothing spiking your blood glucose when you're sitting at a desk.

The problem is when recreational runners start fueling like Kipchoge at 80 grams an hour when their body isn't trained to handle it. There are CGM studies showing blood glucose spiking and spiking until the body bonks from too much fuel going in. The answer is to find your threshold and build toward it gradually, not to jump to the elite number because that's what you read online.

The 90 percent foundation

Charlie made a point that's easy to lose in the noise of the fueling conversation. He has a framework he comes back to: maximize the 90 percent before you worry about the 10 percent.

The massages, the recovery boots, the sodium bicarbonate, the magic gel — none of it matters if you're not sleeping enough, not fueling well outside of workouts, and not showing up consistently. When he was a broke college kid who couldn't afford massages, he figured out what he could control. Running a lot of miles. Sleeping. Being out the door the second his last meeting ended. That was his edge and it worked.

He earns the extras now. He didn't start with them.

Why ProBio exists

Dr. Bubbs spent twenty years watching elite athletes receive individually tailored pill packs and then leave them stuffed between airplane seats or still in their shoes. Compliance was terrible. Not because athletes didn't want to do the right thing, but because the ask was too complicated — six capsules of this, three of that, two more because of the concussion, four more because of the injury.

ProBio was built around the idea that 80 percent of the problems he was seeing were common across athletes. Cover those with two capsules that use the best available forms of each ingredient, get people actually taking it consistently, and then individualize from there. Consistency predicts the outcome. Whether it's training, nutrition, or supplementation, the thing that works is the thing you actually do every day.

He also made a point about elite bloodwork that surprised the room. Despite the miraculous things these athletes do on the field and on the course, their blood panels are often surprisingly average. The more work you do, the more you deplete. Vitamin D, B12, folate, magnesium — these become real issues at high training loads, particularly for female athletes who are building blood every month. Getting tested in December is a good place to start.

Strength training and when to taper it

Charlie strength trains once a week for 90 minutes. If it goes longer than 90 minutes, he leaves. He adds body weight mobility work two or three times a week while winding down before bed. That's it. At 140 miles a week, that's the right amount.

Jason's framework for strength training periodization mirrors the running training itself. Early in a training cycle, build the adaptation. As the race approaches, maintain the quality but reduce the volume. Race week might be 20 to 25 minutes in the gym, four sets of two explosive reps, mostly activating the nervous system. The same way you'd do strides to practice running fast without getting tired, you do low volume explosive lifting to practice power output without accumulating fatigue.

The rule that anchors all of it: strength training exists to make your running better. If it's making your running worse, you're doing too much of it.

The part nobody talks about enough

Somewhere in the middle of this conversation, Charlie mentioned something that deserves more attention than it got. He doesn't take a lunch break. He hasn't finished a Netflix series in years. He works nine to five in marketing at Koros, runs before his first meeting, runs again the second his last meeting ends, and makes every hour count in between.

None of the fueling optimization or strength periodization or micronutrient supplementation matters without that foundation. The fundamentals are unglamorous and they take a long time and they work. That's the whole conversation, really.

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Jon is a runner, cyclist, and podcast host from Boston, MA, who now lives in Boulder, CO. For The Long Run is aimed at exploring the why behind what keeps runners running long, strong, and motivated.

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