For any runner tackling distances longer than a 10K, a successful race is built on more than just training miles; it’s built on smart fueling. The best energy gels, chews, and bars are scientifically formulated tools designed to be used during prolonged exercise—typically any effort lasting over 90 minutes—to solve a critical biological problem. As you run, your body burns through its limited supply of stored carbohydrates, known as glycogen. Once these stores are depleted, you hit the dreaded “wall,” leading to a dramatic drop in energy and performance. By strategically consuming these portable, fast-acting carbohydrate sources during a long run or race, you provide your muscles with the immediate fuel they need to maintain intensity, delay fatigue, and power you across the finish line.
Why Fueling Matters: The Science of Running on Empty
Think of your body’s energy systems like a hybrid car. For short, intense bursts, you rely on immediately available energy. For sustained efforts like a half-marathon or marathon, you switch to your primary fuel tank: glycogen. This is a form of glucose stored in your muscles and liver.
Unfortunately, this tank is not bottomless. The average runner has enough stored glycogen to fuel about 90 to 120 minutes of moderate-to-high intensity exercise. Once you run low, your body is forced to switch to fat as its primary fuel source. While we have plenty of fat stores, converting fat to usable energy is a much slower, less efficient process, forcing you to slow down dramatically.
This physiological event is famously known as “bonking” or “hitting the wall.” It’s a deeply unpleasant feeling of sudden, profound fatigue, dizziness, and even mental fog. The solution isn’t to carbo-load more before the race—it’s to refuel during the race.
By consuming simple carbohydrates from a gel, chew, or bar, you provide your body with an external source of glucose. This influx of sugar enters your bloodstream quickly, fueling your working muscles directly and sparing what’s left of your precious glycogen stores, effectively extending your endurance.
Gels, Chews, or Bars: Choosing Your Fuel Format
The choice between gels, chews, and bars often comes down to personal preference, texture tolerance, and the intensity of your effort. Each format has distinct advantages and disadvantages.
Energy Gels
Energy gels are the most common form of mid-run fuel. They are viscous, syrup-like packets of concentrated carbohydrates designed for rapid absorption. Their main advantage is speed and efficiency; you can swallow one in seconds with a swig of water, and the simple sugars get to work almost immediately.
However, the texture can be a major turn-off for some runners. They can also be messy to open and consume while on the move. It is critically important to consume gels with water to aid digestion and prevent the highly concentrated sugar from causing stomach distress.
Energy Chews (Gummies)
For those who can’t stomach the texture of a gel, energy chews offer a great alternative. These are essentially gummy candies formulated for athletic performance. They provide the same simple carbohydrates but in a more solid, palatable form.
Chews also offer excellent portion control. Instead of consuming an entire packet at once, you can eat one or two chews at a time for a more gradual energy release. The main drawback is that they require chewing, which can be difficult when you’re breathing heavily. They can also get stuck in your teeth.
Energy Bars
Energy bars feel more like “real food” and are often preferred for longer, lower-intensity efforts like ultramarathons, trail running, or cycling. They typically contain a mix of simple and complex carbohydrates, and sometimes small amounts of protein and fat from ingredients like oats, dates, and nuts.
This composition provides more sustained energy and can help fight off true hunger over many hours. The downside is that they are slower to digest. The presence of fiber, fat, and protein means they take longer to break down, making them less ideal for high-intensity racing where you need energy now.
What to Look For: Decoding the Nutrition Label
Not all energy products are created equal. Understanding the key ingredients will help you choose the best fuel for your body and your goals.
Carbohydrate Type and Amount
The most effective energy products use multiple transportable carbohydrates, most often a combination of glucose (or its variants like maltodextrin) and fructose. Your body has different “pathways” to absorb these sugars. Using both at once is like opening a second lane on a highway—it allows your body to absorb more carbohydrates per hour (up to 90 grams) than it could with a single source alone, while also reducing the risk of gastrointestinal (GI) upset.
As a general guideline, runners should aim to consume 30-60 grams of carbohydrates per hour for efforts lasting longer than 90 minutes.
Electrolytes
When you sweat, you lose more than just water; you lose critical minerals called electrolytes, primarily sodium and potassium. These are essential for maintaining fluid balance, proper muscle function, and nerve signaling. A lack of electrolytes can contribute to dehydration and muscle cramping. Most gels and chews contain added sodium to help replenish what you lose through sweat.
Caffeine
Caffeine is a well-researched performance enhancer. It can lower your perception of effort, making hard running feel easier, and increase mental alertness and focus. Many brands offer caffeinated versions of their products, typically containing 25-50mg of caffeine per serving.
However, caffeine can cause jitters or GI issues in some individuals. It’s crucial to test your tolerance in training before relying on a caffeinated gel during a big race.
Our Top Picks: The Best Energy Products for Runners
Our editors have tested dozens of products on long runs and race days. These are our top recommendations based on effectiveness, taste, and digestibility.
Best Overall Energy Gel: Maurten Gel 100
Favored by elite marathoners like Eliud Kipchoge, Maurten has revolutionized fueling with its hydrogel technology. The gel itself is formulated to react with the acid in your stomach, forming a gel that encapsulates the carbohydrates. This allows it to pass smoothly into the intestine where it can be absorbed, dramatically minimizing the risk of GI distress. Its ingredient list is simple and effective: water, glucose, fructose, and electrolytes.
Best Tasting Energy Gel: Huma Chia Energy Gel
If you prefer natural ingredients, Huma is an excellent choice. Made with a base of fruit puree, cane sugar, and ground chia seeds, these gels have a more palatable, food-like taste and texture. The fiber from the chia seeds helps modulate the absorption of sugar and water for a smoother energy curve. Flavors like “Strawberries” and “Mangoes” taste exactly as advertised.
Best Caffeinated Gel: GU Roctane Energy Gel
GU’s Roctane line is designed for maximum performance during the most demanding efforts. In addition to a dual-source energy blend, it contains a higher concentration of electrolytes (especially sodium) to combat sweat loss and branched-chain amino acids (BCAAs) to reduce muscle damage and mental fatigue. The caffeinated versions provide a reliable 35mg kick to sharpen focus in the later stages of a race.
Best Overall Energy Chews: Clif Bloks Energy Chews
Clif Bloks are a time-tested favorite for a reason. They are easy to carry, easy to portion, and have a soft, easy-to-chew texture that doesn’t get too hard in the cold. The streamlined packaging makes it easy to push one blok out at a time. With a huge variety of flavors and several caffeine levels (from 0mg to 100mg per serving), there is a Blok for every runner and every occasion.
Best Natural Energy Chews: Skratch Labs Sport Energy Chews
Developed by exercise physiologist Dr. Allen Lim, Skratch Labs products are known for their simple, real-food ingredients. These chews are made from cane sugar, tapioca syrup, and real fruit, and are coated in a sour powder that not only tastes great but also prevents them from sticking together in the package. They provide a clean, quick source of energy that’s gentle on the stomach.
Best Energy Bar for Long Efforts: Picky Bars Ah, Fudge Nuts!
For those long days on the trail or during an ultramarathon, a bar is often more satisfying. Picky Bars were developed by professional athletes and strike an ideal 4:1 carbohydrate-to-protein ratio for sustained energy and muscle support. Made with dates, nuts, and agave, they taste like a treat but are built for performance. They are soft, easy to chew, and provide lasting fuel without feeling heavy.
How to Fuel Like a Pro: Timing and Strategy
Buying the right fuel is only half the battle. Using it correctly is what makes the difference.
When to Start Fueling
The most common mistake runners make is waiting too long to start fueling. Do not wait until you feel tired. The goal is to stay ahead of energy depletion. For any run planned to last 75 minutes or more, take your first gel or serving of chews around the 45-minute mark.
How Often to Fuel
Consistency is key. After your first fuel intake, plan to take another serving every 45 to 60 minutes thereafter. This creates a steady supply of energy to your muscles, preventing the peaks and crashes that can come from inconsistent fueling.
The Importance of Hydration
Always—and this cannot be overstated—take energy gels with water. Consuming a gel without water creates a highly concentrated sugar solution in your stomach, which can pull water from your bloodstream into your gut and cause cramping, nausea, and bloating. Taking it with a few sips of water from an aid station dilutes the gel, making it much easier for your body to absorb quickly and without issue.
Practice Makes Perfect
The golden rule of racing is: nothing new on race day. This applies especially to your nutrition plan. Use your long training runs to experiment with different products, flavors, and timing strategies. Train your gut just like you train your legs. Figure out what works for your body so you can step up to the starting line with a confident, proven fueling plan.
Conclusion: Fueling Your Way to the Finish Line
Proper fueling is not an optional extra for endurance runners; it is a fundamental pillar of performance, just as important as your weekly mileage and speed workouts. By understanding the science behind why you need to fuel, choosing the right format for your preferences, and meticulously practicing your strategy, you can avoid hitting the wall. Dialing in your nutrition will not only help you feel stronger and run faster but will transform your relationship with distance running, empowering you to conquer your goals and cross the finish line with energy to spare.
