SiS Beta Fuel has 40 g of carbs in a gel, so you carry fewer and an hour costs less. GU Liquid Energy has 24 g, 5 times the sodium and flavors with caffeine.
GU Energy
24 g of carbs in a 60 g (2.1 oz) serving, from maltodextrin and fructose.
Choose it if
Science in Sport
40 g of carbs in a 60 g (2.1 oz) serving, from maltodextrin and fructose.
Choose it if
Updated October 20, 2026 · numbers from each brand's label, verified by CarbRate
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GU Energy Liquid Energy
Science in Sport Beta Fuel Gel
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| Liquid Energy | Beta Fuel Gel | |
|---|---|---|
| Carbohydrate | 24 g | 40 g |
| Serving weight | 60 g (2.1 oz) | 60 g (2.1 oz) |
| Calories | 100 | 160 |
| Sodium | 75 mg | 15 mg |
| Potassium | not listed | not listed |
| Caffeine | 0 mg | 0 mg |
| Protein | not listed | 0 g |
| Carbs from | maltodextrin, fructose | maltodextrin, fructose |
| Cost per serving | $2.50 | $3.33 |
| RC Science Score | 92 | 100 |
2 of 4 differ: vegan and gluten free.
GU Energy Liquid Energy
Science in Sport Beta Fuel Gel
Set your carbs an hour and race length. Both options hit the same target.
| Liquid Energy | Beta Fuel Gel | Half each | |
|---|---|---|---|
| Gels an hour | 2.5 | 1.5 | 1.3 + 0.8 |
| Gels for the race | 10 | 6 | 5 + 3 |
| Weight to carry | 600 g 21.2 oz | 360 g 12.7 oz | 480 g 16.9 oz |
| Sodium an hour | 188 mg | 23 mg | 105 mg |
| Cost for the race | $25.00 | $19.98 | $22.49 |
| Half each takes half your carbs from each. | |||
Your own carbs an hour depend on your body and goal time.
Build my free planBoth pouches weigh 60 g (2.1 oz), but Beta Fuel carries 40 g of carbohydrate and GU carries 24 g.
That means a 4-hour marathon at 60 g an hour takes 6 Beta Fuel gels or 10 GU packets. Beta Fuel costs more per gel, $3.33 against $2.50, and still works out cheaper per gram of carbs: about 8 cents against 10 cents.
Three gels that each lead on one thing.
More carbs for the money
Carbs Fuel Original Energy Gel50 g of carbs in 85 g (3.0 oz) · $1.97
Lightest to carry
Endurance Tap Maple Syrup and Ginger Double Tap Energy Gel50 g of carbs in 56 g (2.0 oz) · $4.44
Most carbs per serving
Santa Madre Unusual Gel 60g Unflavoured Energy Gel60 g of carbs in 100 g (3.5 oz) · $5.25GU, with 75 mg a packet against 15 mg in a Beta Fuel gel. On Beta Fuel, plan your sodium from your drink or a separate electrolyte.
Yes, once your stomach is trained. Both mix maltodextrin and fructose, which is what lets a trained stomach go past about 60 g an hour toward 90 g. That's 2.25 Beta Fuel gels or almost 4 GU packets an hour.
The Beta Fuel gel here has none. GU Liquid Energy's Plain & Simple flavor has none either, and some GU flavors add caffeine.
CarbRate builds your fueling plan from the amount of glycogen you burn, your goal time, your course and the gels you use.