Why Gatorade Is Sabotaging Your Ultramarathon: The Simple Carb Problem

The Sugar-Fueled Illusion of Performance

Picture this: You're 60 miles into a 100-mile ultramarathon. You've been dutifully sipping your sports drink every 15 minutes, just like the conventional wisdom suggests. Yet your stomach is churning, your energy is crashing, and you're questioning every life decision that led you to this moment on a remote mountain trail.

Ultrarunners work so hard to avoid GI distress during races but something hiding in that brightly colored bottle you've been sipping from for hours is working against you.

The Science Behind Carbohydrate Oxidation

To understand why simple sugars from sports drinks can sabotage ultramarathon performance, we need to examine how the body processes different types of carbohydrates during prolonged exercise.

Research on carbohydrate oxidation during prolonged exercise reveals that the body has distinct limitations on how quickly it can process and utilize ingested carbohydrates. Studies revealed that maximum carbohydrate oxidation rates plateau at approximately 1.0-1.1 grams per minute for single-source carbohydrates like glucose, the primary sugar in most sports drinks.

This reveals the fundamental problem that when you consume simple sugars at rates higher than your body can oxidize them, you're essentially flooding your system with fuel it cannot use efficiently.

The Gastric Emptying Bottleneck

The first barrier ultrarunners encounter with simple sugars is gastric emptying. Research on ingested carbohydrate regulation demonstrates that high-osmolality solutions (characteristic of sugar-heavy sports drinks) empty from the stomach more slowly than lower-osmolality alternatives.

This delayed gastric emptying creates several cascading problems:

Gastrointestinal distress: Liquid sloshing in your stomach for hours.
Delayed energy availability: Fuel sitting in your stomach instead of reaching your muscles.
Nausea and vomiting: The infamous "ultrarunner's stomach" that can end your race.
Reduced hydration: When your stomach won't empty, you can't hydrate effectively.

Simple vs. Complex Carbohydrates: Understanding the Difference

Not all carbohydrates are created equal, especially when you're asking your body to function for 20-40 hours straight.

Comparing Carbohydrates

Simple Carbohydrates (The Problem)

What they are: Monosaccharides and disaccharides: glucose, fructose, sucrose, found in sports drinks and candy.

How they behave:

Rapidly absorbed (when tolerated).
Cause sharp blood sugar spikes followed by crashes.
High osmolality leads to GI distress.
Provide quick but unsustainable energy.
Can overwhelm intestinal glucose transporters.

Complex Carbohydrates (The Solution)

What they are: Polysaccharides found in whole foods like potatoes, sweet potatoes, rice, and maltodextrins.

How they behave:

More gradual digestion and absorption.
Stable, sustained energy release.
Lower osmolality reduces GI distress.
Better tolerated during ultra-distance events.
Provide accompanying nutrients (electrolytes, vitamins).

The Potato Revolution in Ultrarunning

Ask any experienced ultrarunner about their fueling strategy, and many will enthusiastically tell you about boiled potatoes. This isn't just ultra-culture folklore, there's solid science behind it!

Potatoes offer several advantages over sports drinks:

Complex Carbohydrate Structure: The starch in potatoes (amylopectin) is oxidized at high rates similar to glucose, according to research on carbohydrate feeding strategies, but with better GI tolerance.
Natural Electrolyte Content: Potatoes are rich in potassium (421mg per medium potato), magnesium, and sodium when salted, exactly what you're losing through sweat.
Psychological Satisfaction: Real food provides a mental boost that sweet sports drinks cannot match at 3 AM on a mountain trail.
Lower Osmolality: Easier on the stomach, reducing the risk of the GI issues that force many runners to DNF.

The Blood Sugar Rollercoaster

One of the most insidious effects of relying on simple sugars is the blood glucose volatility they create. When you consume high amounts of glucose or sucrose:

Blood sugar spikes rapidly.
Insulin surges to manage the spike.
Blood sugar crashes below baseline.
You experience bonking, fatigue, and cognitive impairment.
You reach for more simple sugars to compensate.

This cycle becomes increasingly problematic as races extend beyond the first couple of hours. The metabolic stress compounds, your insulin sensitivity decreases, and your body becomes less efficient at utilizing the very fuel you're consuming.

Practical Fueling Recommendations for Ultrarunners

Replace sports drinks with electrolyte solutions!

Modern electrolyte supplements provide the minerals you need without the sugar overload: Hammer Nutrition Fizz, or Endurolytes are well balanced electrolyte-only formulations without the high sugar content.

Want to control your carbohydrate/electrolyte mix even more? Try these homemade solutions.

Mix 1/4 tsp salt, 1/4 tsp lite salt (potassium), and a squeeze of lemon in 20oz water.

Bone broth: Warm, salty, and comforting during night sections

Embrace Real Food Fueling

Build your nutrition plan around whole food sources:

Boiled Potatoes:

Prepare small cubes, lightly salted
Easy to carry in ziplock bags
Consume 1-2 cubes every 30-45 minutes

Sweet Potatoes:

Higher in vitamins A and C
Naturally sweet without added sugar
Excellent for cooler weather races

Rice Balls (Onigiri):

Sticky rice formed into palm-sized portions
Can wrap in nori for additional minerals

Bananas:

Natural package, easy to carry
Potassium-rich
Fruits are a mixture of simple and complex carbs

Strategic Use of Maltodextrin-Based Products

If you prefer engineered nutrition, choose products based on maltodextrins rather than simple sugars. Research shows maltodextrins are oxidized at rates similar to glucose but with better gastrointestinal tolerance.

The Multiple Transportable Carbohydrate Strategy

If you do choose to use some simple carbohydrates, leverage the science of multiple transportable carbs. Research indicates that glucose-fructose combinations can achieve oxidation rates up to 1.75 g/min, that's about 175% more than single sources.

Training Your Gut Before Racing

Perhaps the most important factor in ultramarathon fueling success isn't what you consume, but training your gastrointestinal system to tolerate and process food during exercise. The research on carbohydrate regulation suggests that gut training can potentially upregulate glucose transporters (SGLT1) and improve tolerance to feeding during exercise.

Basic gut training protocol:

Practice eating during ALL long training runs.
Gradually increase the volume and frequency of feeding.
Experiment with different food types and timing.
Simulate race-day fueling during training runs of 3+ hours.
Note what works and what doesn't in a fueling journal.

The Bottom Line: Ditch the Gatorade!

Research reveals that relying on simple sugars from sports drinks is a suboptimal fueling strategy for ultramarathons. The science of carbohydrate oxidation points toward a superior approach of separating your hydration from your calories. Use electrolyte-only solutions for hydration and consume real food or complex carbohydrates for energy. This will provide you with more stable energy while reducing GI distress.

Your next 100-miler doesn't have to involve a stomach full of sloshing Gatorade and the inevitable bonk at mile 70. Try boiled potatoes, electrolyte water, and the occasional banana instead. Your gut, and your finish time, will thank you. Go get that buckle!