When it comes to nutrition for runners, there’s no shortage of confusing, outdated, or completely wrong advice floating around on the internet or in your running group. If you’ve ever wondered why your stomach revolts mid-run, how many gels you really need, or whether you should be carbo-loading before every race, this post will clear it up.
I recently sat down with Kristy Bauman, RD, also known on Instagram as @marathon.nutritionistto debunk the most common running nutrition myths. Kristy works with runners of all levels to improve fueling, reduce GI discomfort, and build confidence for race day. And let me tell you: her practical, scientific explanations are just what most runners need.
Here’s everything we covered and the truth behind the biggest myths in the world of runner’s nutrition.
Myth #1: “Gels cause gastrointestinal problems.”
Many runners assume that gastrointestinal distress is caused by whatever fuel they consume during a run. But as Kristy explained, that’s usually not the case.
“Your stomach is a muscle. Just like you train your legs to run long distances, you need to train your stomach to digest food while you run,” says Kristy.
Oftentimes, gastrointestinal issues come from dehydration, not gels. When you’re dehydrated, blood flow to your gut is reduced, making digestion more difficult.
What to do instead:
Train your gut gradually. Start with half a gel, some chews or small amounts of sports drink and always mix the fuel with water. As Kristy puts it, “Your fuel needs liquid to digest.”
Myth #2: “One or two gels are enough for a half or full marathon.”
Both Kristy and I recall seriously under-fueling with just 1 or 2 gels during the first few days of running. Most runners do this and it’s a problem. Here’s why:
During long runs and races, your body burns through glycogen (stored carbohydrates) quickly. When glycogen is depleted, you “hit the wall” because your body is forced to rely on fat as its primary fuel source, which is much slower to access.
“Your body is constantly using carbohydrates as its primary fuel source,” explains Kristy. “You have to make sure you’re getting enough.”
A single gel usually contains only 20-25 grams of carbohydrates. But the recommended intake for endurance athletes is 30-60 grams of carbohydrates per hour.
What to do instead:
Aim to fuel every 30 minutes, not once or twice altogether. Start feeding early, before you get tired, because the gels take about 15-20 minutes to hit your bloodstream.
Myth #3: “You don’t need electrolytes – just drink water.”
You’re probably not fueling at all if water is the only thing in your bottles over time.
Hydration is not just water. It has to do with maintaining proper fluid and electrolyte balance.
“When you sweat, you lose sodium,” says Kristy. “If you only drink water, you may experience symptoms similar to dehydration because your body needs that balance.”
What to do instead:
Most runners need 300–600 mg of sodium per hourdepending on the rate and duration of sweating. Sports drinks, electrolyte powders, salt capsules or sodium-rich gels can help you reach your goal.
Myth #4: “Protein is the most important macronutrient for runners.”
Protein takes so a lot of publicity these days when entire grocery store aisles are filled with “protein added” products. But for endurance athletes, carbs are still the #1 fuel source.
Kristy sees many runners inadvertently displace carbs because they are too focused on hitting high protein goals.
What to do instead:
Balance is key. After a workout, aim for 20 grams of protein and 60 grams of carbs—a 3:1 ratio for optimal recovery. (Check out this list of plant-based examples.) If solid food doesn’t appeal, try chocolate milk, an oat smoothie, or a drinkable yogurt.
Myth #5: “Carb loading is essential for every race.”
You do it not you need to carb load for every 5K, 10K or even every half marathon.
“I encourage people to think about their goal for the race,” says Kristy. “Not everyone needs to carb load — especially for half.”
Carb-loading is a great strategy for full marathons, heavy training blocks, or A-goal races—but for occasional or lower-intensity races, your usual eating patterns may be enough.
What to do instead:
For most half marathoners: focus on balanced meals with a little more carbohydrate. For full marathons or PR efforts: start a structured carb load 1-2 days out, including liquid carbs (juice, sports drink) to reduce discomfort.
Myth #6: “Running fasted helps you burn more fat.”
Morning runners often run out the door with nothing in their stomachs. But fasted running isn’t the fat-burning hack people think it is.
“By morning, a lot of your glycogen is gone,” Kristy explains. “If you run low on fuel, you run the risk of your body breaking down protein, also known as muscle, for energy.”
Running fast can reduce performance, delay recovery, and increase the risk of injury, especially for women.
What to do instead:
eat something –anything—before you run. Quick, easy options include:
- Graham crackers
- A handful of raisins
- Bags of applesauce
- A slice of toast with jelly
- Dried mango
- Half a granola bar
As Kristy puts it: “A few bites are better than nothing.”
Myth #7: “If you’re not hungry after a run, you don’t need to eat.”
This trips up many runners. It’s normal not to feel hungry right after a hard run—but delaying eating can lead to overeating later and a slower recovery.
“By the end of the day you can feel predatory and grab anything in front of you,” notes Kristy. “That’s what your body is catching up to.”
What to do instead:
If solid foods don’t appeal, drink calories:
Your muscles are primed to absorb nutrients within 30-60 minutes, so take advantage of this window.
Final Thoughts: Mastering Runner’s Nutrition is a game changer
So much of running performance comes from consistent, purposeful fueling, not restriction, “hardening” or magic supplements.
As Kristy reminds us:
“Sports nutrition is different than regular nutrition. Runners need to think about carbs, hydration and timing differently to feel and perform at their best.”
Whether you’re training for your first half marathon or chasing a marathon PR, taking the time to understand runner’s nutrition will help you feel better, recover faster, and enjoy running more.
