03 Dec How to Run a Faster Marathon: The Evidence-Based Nutrition Boosts Most Runners Skip

How Much Faster Can You Really Get as a Runner?

If you’ve ever wondered, “How much faster can I run a marathon?”, you’re not alone. It’s a question I ask myself often—both as a runner and as a coach.

We all see those stories on social media: people shaving hours off their marathon time, runners finally qualifying for Boston after years of grinding, or someone who from their first marathon to their 10th make massive leaps in performance. It’s inspiring, but it also makes many runners wonder: Is that kind of progress possible for me?

Spoiler: Yes! Very often, it is. In fact, I truly believe the sky is the limit for so many runners, and that we rarely reach our full performance potential. But the path to getting faster is a blend of science, strategy, and long-term consistency.

In this article, I’m sharing some insight into the factors that impact speed potential and running development over time.

But, most importantly I’m sharing some of the best kept secrets that can help you run faster at your next race, without needing more months or even years of training under your belt.

Genetics Matter… But Not as Much as You Think

Yes, genetics play a role in running potential. Research shows that certain genetic variants- like ADRB3, NFIA-AS2
& ACTN3 influence baseline fitness, training response, or muscle fibre development. That means if 100 people start running at age 30 with zero experience, a small percentage will naturally progress faster, even if everyone followers the same training program.

And this makes sense, right? We all know people who seem to be just naturally ‘gifted’ in the sport of running, and while yes, that might mean that this person consistently has a faster marathon time than you with less time or training, it doesn’t take away from how much YOU can improve your own race times over the years.

But here’s the important part:
Genetics do not determine who “gets to be” a runner. But, it can determine a realistic timeline for you to reach your personal goals. 

I personally possess none of the so-called “ideal endurance athlete” genes, yet here I am- running marathons and helping thousands of runners get stronger every year. Genetics might influence how quickly you improve, but they absolutely do not define your performance ceiling.

For some runners, progress just takes a little longer. And that’s normal.

Is Age The Big Limiter for Recreational Runners?

One of the biggest fears many adult runners have is that because they didn’t start running in their teens or 20’s, once they hit 30, 40, or 50 that their chance at getting faster is over. But the science suggests that age doesn’t automatically mean you’re stuck slowing down once  certain milestone birthday has passed. What matters far more is your consistency with your training if you took up running as an adult.

Yes- VO₂ max and performance tend to decline with advancing age, but reducing your training loads (or being inconsistent with training) is often the bigger factor driving that decline in middle age.

Why “Starting Late” Often Means Room to Grow

For many adult-onset runners, their starting fitness baseline is lower. That means in your early years of running, even if you do begin at 30, 40, or 50 there is a lot of untapped potential. Rather than slowing down with subsequent years of racing, you can actually get faster over the subsequent decades because you weren’t starting at your physical peak.

Because your starting baseline is lower, gains tend to be larger (relatively speaking), and the potential for improvement remains substantial, especially if you stay consistent and smart with your training.

So if you’re an adult runner worried about “being too old”  I want you to know this: many of the well-studied masters athletes who maintain training keep far more of their fitness than most people realize.

And if you stay committed, structured, and intentional- your best mile, your strongest race, and maybe even your biggest PR could still be ahead of you.

Training: The Biggest Factor in Your Potential

Genetics and age can set the stage for your fitness baseline and can help determine how quickly you gain strength or endurance. However, your actual strategy and approach to training is also key in how quickly you make progress year over year.

A truly effective training plan:

• Is personalized to your body and your goals
• Builds the right systems (aerobic base, lactate threshold, VO₂ max, neuromuscular efficiency)
• Keeps you healthy so you can remain consistent season after season
• Fits your life so you can find a balance of training and life that works for you long term.

And consistency is everything.

Think back to your first marathon:
Maybe you trained for 4–5 months, ran mostly easy miles, did a few long runs, used run/walk intervals, and knew nothing about fueling or hydration. And you finished, but it was a slog.

But now imagine layering in:

• Year-round base training and aerobic development
• Better quality workouts that build on your current fitness over tim
• Strong recovery habits
• A well-designed race-specific plan

The improvements that follow often shock people, especially compounded over time.

The Race-Day Speed Boosts (You’re Probably Not Using Yet)

Next, let’s talk about things you can do without changing your training at all, turning back the clock 20 years, or even swapping genes with someone else. Just optimizing what you’re already doing, but seeing potentially massive payoffs in your race times.

And yes… they’re free. Basically.

1. A Proper Taper (2–3% Performance Boost)

A well-executed taper can make you 2–3% faster, according to multiple meta-analyses on endurance tapering.
For a 4-hour marathoner, that’s 7+ minutes, simply by allowing your body to fully absorb your training in the weeks leading up to your race.

The key principles of a good taper are simple:

• Longer races = longer taper
• Reduce volume, maintain intensity
• Do not replace reduced running with extra strength or cross-training
• We’re aiming for recovery, not filling your schedule with different activities

If you want the full deep dive on all things tapering, check out Season 2, Episode 27 of The Fuel Run Recover podcast.

2. Carb Loading Done Right (2–3% Performance Boost)

Carb loading works- when you do it correctly.
For races longer than 90 minutes, research consistently shows 2–3% performance improvements with proper carb loading.

But, most runners I work with make a lot of mistakes when it comes to carb loading.

Things like:

• Trying to cram 400–700g of carbs into one evening, meaning serious GI upset on race day
• Eating unfamiliar foods during your carb load that you aren’t used to eating before running
• Not practicing carb loading during training so it’s all brand new the day before your race

Instead, we need to take the right approach to carb loading, meaning:

• Spread carb-rich foods throughout the day (I like setting targets for morning, afternoon, and evening)
• Keep it familiar with foods you already eat all the time during your training cycle
• Practice your carb-load before your weekly long runs so it’s routine by race day

You should show up to the start line feeling energized, not bloated and unsure if your stomach is going to totally turn on you mid-race.

Read more about fueling for your long runs here!

3. Intra-Race Fueling (2–3% Performance Boost)

If you care about performance, intra-race fueling is a non-negotiable.

Research shows that consuming 60g+ of carbs per hour during endurance events significantly boosts performance and reduces time to exhaustion. In marathons, it can absolutely be the difference between finishing strong and reaching your goal or bonking.

If you’ve ever hit the wall, you know what I mean. Pace drops of 37–40% aren’t uncommon once you bonk, and that adds major time to your race.

Fuel early, fuel often, and you’ll set yourself up to avoid a late race collapse.

Listen to this episode of The Fuel Run Recover podcast for more about race day fueling

4. Your Hydration Strategy (Individual, but Crucial)

Once you lose about 2% of your body weight in sweat, performance begins to decline. This looks like increasing effort, higher heart rate, and pace slowing despite wanting to move faster. How much sweat you actually lose during a run, and how much your performance suffers as a result also depends on a lot of factors, including:

• Temperature
• Humidity
• Sodium losses
• How hot you feel

A personalized hydration plan- based on your sweat rate, race conditions, and fueling strategy can make the difference between a strong finish and a miserable mid-race fade.

Read more about hydration and it’s impacts on your performance here

So… How Fast Can You Get?

Honestly?
I believe the sky is the limit for most adult runners.

The vast majority of runners I work with are nowhere near reaching their true potential. Not because they lack talent, have the wrong genes, or are too old, but because they’ve never combined training, fueling, hydration, and recovery at the same time.

When you bring all of these together?
That’s when you start making breakthroughs.

And yes, if you’re keeping track of the math:

• Taper: 2–3%
• Carb loading: 2–3%
• Intra-race fueling: 2–3%
• Hydration: variable but meaningful

In theory, that’s up to ~9% faster or more, or 20+ minutes for a 4-hour marathoner.
Do they perfectly stack like my examples? Not exactly, but the point is this:

Most runners are leaving huge performance gains on the table.

Want to hear more about how much faster I think you can get as a runner? Check out season 3, episode 42 of The Fuel Run Recover Podcast!

If you’re serious about getting faster, don’t leave your nutrition to guesswork.
Take my free Runner’s Fueling Audit and learn where you’re under-fueling, over-pushing, or missing key race-day strategies that could be costing you minutes.

Start your audit now.