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Your fueling strategy should be personalized, including how and when to consume energy gels. There are some general guidelines, but it takes practice and trial and error to get everything dialed in for that all-important race day.

Below are the dos and don’ts the Runivore team recommended over the years in one convenient place. It’s a great way to discover or revisit fan-favorite articles. Click on the hyperlinks for more in-depth information and create an individualized fuel plan.


DO practice and DON’T try anything new on race day

Like your heart, lungs, and legs, you can also train your stomach. For us amateurs and weekend warriors, fueling your daily workouts with energy gels is unnecessary, unsustainable, and, frankly, unhealthy and kind of gross (I’ve yet to meet someone who thinks energy gels are genuinely delicious).


However, do pick minor races or workouts that simulate your A race to test different options – a 20+km progression run for a marathoner or a century ride for an Ironman hopeful.

DO customize for different event types and DON’T expect one size to fit all

A relatively fit runner can store between 90-120 minutes worth of glycogen going at marathon to near lactic threshold pace.

Anything under 90 minutes, a refuel may be unnecessary. Also, if you plan to go at an easy-to-moderate pace that won’t deplete glycogen as quickly, like for an ultramarathon, you may not need to eat as often. 

Digestion diverts blood to your stomach from other bodily systems (for example, muscle and cooling), so it’s a plus if you can go without eating or eat less mid-race.

DO calculate and DON’T just go by feel

Here’s a good starting point. Consume 1g of carbohydrate per kg of body weight per hour. A 60kg athlete should take in 60g of carbohydrates each hour, about 2-3 energy gels

Don’t forget to test things out during training. If you find out your body doesn’t need as much, you can carry less weight. If you need more than that, bonking awaits, or worse, your blood sugar plummets. Both ain’t fun.

Tired Runner

DO your research on ingredients and nutritional content and DON’T blindly accept marketing hype.

Hydrogel, isotonic, all-natural, organic, BCAA, superfood, instant boost…the list of buzz words is endless. While it’s excellent that energy gel makers continue to innovate, you should do your research, especially if you have a sensitive stomach and food allergies. The latest technology might sound great on paper, but it might not suit you. 

Find out how many calories, carbohydrates, and electrolytes are available per sachet to be precise with your fueling for pre-, mid-, and post-race. Once again, every athlete is different.

Study what the pros use and what other’s are saying, but ultimately it’s about you. Research and practice to ensure you have picked the best sports fuel for you.

DO hydrate but DON’t over drink

Energy gels are concentrated sugar water made for replenishing carbohydrates and require water intake to assist digestion. 

A typical gel is 30g and provides 20g of carbohydrates and 100 calories. The rule of thumb is every 20-25g of carbohydrates require 250 ml of water to process. Not drinking enough fluids is often the reason for upset stomach (sugar spike) or dehydration (water needs to be drawn from other parts of the body for digestion), and sweetness fatigue (need water to chase down the sweet taste).

On the other side of the ledger, too much water is also a problem. Hyponatremia is when you drink too much, lowering electrolyte concentration in the body. Symptoms are nausea, cramps, and vomiting. Plus, exercising with a stomach full of liquid sloshing around is not the recipe for breakthrough performances.

DO take gels early and DON’T play catch up

If you had a carbohydrate-rich breakfast 2-3 hours before the race, you should be fairly topped up at the start line. Take your first gel 30-45 minutes after the gun, and it goes without saying that remember to evenly space out the energy gels afterward. Taking two or three at a time spikes blood sugar and may cause gastrointestinal distress. 

Mouth-to-muscle time can range from 5-20 minutes, so “preemptive strike” is the name of the game. Don’t wait for the dreaded “empty” feeling before you refuel. By then, it’s often too late.

Do practice optimal daily fueling and DON’T wait until the last minute

Getting the best performance out of yourself is more than the energy gels, sports drinks, or energy bars you bring to a race. 

Race-day fueling begins way WAY before you toe the line and starts with what you eat daily to fuel and recover from workouts. Here is a complete guide to fueling, from lifestyle to recovery to race day.

DO practice opening an energy gel on the move and DON’T pick something that doesn’t fit your pocket or pouch

Here are a few key points:

  • Easy to tear open (here’s a packaging that requires only one hand)
  • Compact and fits in your fuel-carrying gear (belts, hydration vests, backpacks)
  • Lightweight yet packs ample energy
  • Doesn’t make a sticky mess during consumption

You are already pushing your body and mind to the limits. Struggling to open a sachet, sticky hands, gels falling out of your pocket, extra weight…these are the things you can do without.