WHY FUELING LOOKS DIFFERENT IN HALVES AND FULLS

Both half marathons and full marathons rely on carbohydrates as their primary fuel. The difference is how fast you use it and how long you need it.

The Half Marathon Strategy

For many runners, a half-marathon lasts 70 to 120 minutes.

Because the race is shorter, your stored energy (glycogen) usually lasts long enough to support your pace. Fueling helps keep your blood sugar steady, but your body’s natural stores still do most of the heavy lifting.

• The Goal: 30 to 60 grams of carbohydrate per hour.
• The Carb Choice: Go By Preference: Because you are aiming for under 60g per hour, you don’t need complex dual-source blends (like glucose/fructose mixes). Your body can typically absorb this amount of glucose on its own.

THE FULL MARATHON STRATEGY

A marathon is different. You are out there for several hours, and your stored energy fades steadily as the race goes on.
Most marathoners need 60 to 120 grams of carbohydrate per hour to stay steady.
Once you try to eat more than 60 grams, your body needs help absorbing it all. This is where combining glucose and fructose helps.

Think of it like opening a second door to let people into a building

• Door 1 (Glucose): Can handle about 60 grams per hour.
• Door 2 (Fructose): Opens a second route so you can take in more fuel without overwhelming your stomach.

The races look similar from the outside, but inside your body, they are not. The goal is simple: give your body steady energy so you can run the way you trained.

HOW TO FUEL YOUR SPRING HALF MARATHON

A half-marathon is intense. Your pace is high, and your stomach prefers simplicity at these speeds.

Practice this during steady long runs and race-pace segments. You want your fueling rhythm to feel familiar, not forced.

HOW TO FUEL YOUR FULL MARATHON

A full marathon is an energy-management challenge. If your fuel runs low, your pace drops quickly.

The Strategy:

• The Amount: 60 to 90 grams per hour is the standard recommendation.
  • The Elite Frontier (90–120g): Recent research from Liverpool John Moores University (England, UK) suggests that elite and high-performance runners can benefit from pushing this to 120g per hour. 
  • Note: This higher range is only recommended if you have a high metabolic output (running fast) and have specifically trained your gut to handle it.
• The Product: A gel like the SiS BETA FUEL that blends glucose and fructose. This allows you to absorb more total energy at high carb amounts.
• The Timing: Take one gel every 20 to 30 minutes to support steady energy throughout the race.

Practice this during your long runs, long workouts, and marathon-pace efforts. Just like training your legs, training your stomach takes repetition. Over time, your gut becomes more comfortable with higher-carb fueling.

TROUBLESHOOTING COMMON PROBLEMS

My stomach feels unsettled. Slow down your fueling slightly for a week. Smaller bites or sips can help. Your stomach adapts with practice.
I forgot to fuel. Set a watch alert every 25 minutes. Small reminders make a big difference.
I slow down mid-run. Stick with your plan and timing, unless your stomach tells you otherwise. Even at easier paces, steady fueling keeps your blood sugar stable.
I feel great early and don’t want to take fuel yet. Take it anyway. Early fueling protects your later miles.

THE TAKEAWAY

Fueling does not have to be complicated. It just needs to match the race you are training for.

• Half marathons run fast. Simple fueling works well with single-carb source gels, like SiS GO Gels.
• Full marathons run long. Higher-carb fueling with SiS BETA Fuel Gels helps keep you steady.

Start practicing now. Give your stomach time to learn the plan. Your legs will feel the results in April and May.