How To Stack Your Sports Nutrition: Carbs, Electrolytes & All-In-One Mixes

A carb drink mix, an electrolyte tab, two gels and a salt capsule - is that a plan, or a guess? Stacking means combining products on purpose so you hit three separate targets every hour: carbs, sodium and fluid. ¹˒².  Get it right and you can hold your pace without a sloshing gut. Get it wrong and you double up on some things, miss others, and find out at 30 km. Here's how to build a stack that works for running, cycling and triathlon.

Table Of Contents

• Why Stacking Matters

• Know Your Building Blocks

• How To Build Your Stack

• Stacks By Sport

• Common Stacking Mistakes

• FAQ’s
  
  

Why Stacking Matters

No single product is perfect for every athlete, every hour and every weather forecast. Each one locks in a ratio of carbs to sodium to fluid - and your needs rarely match that ratio exactly.

Think of your race-day nutrition as three dials you set separately:

• Carbs (g/h). Typically 30-60g/h for 1-2.5 hours and up to 90g/h for longer events, depending on your gut training. ¹˒²

• Sodium (mg/h). A common starting point is 300-600mg/h, but sweat sodium varies more than fivefold between athletes, so salty sweaters may need more. ³˒⁴

• Fluid (ml/h). Around 400-800ml/h for most athletes, adjusted for sweat rate, heat and body size. ⁵

Stacking lets you set each dial on its own instead of letting one product set all three for you.

Know Your Building Blocks

Every product in your stack does one, two or all three jobs. Check the label for grams of carbs, milligrams of sodium and the fluid it's mixed with - that's all you need to plan.

All-in-one vs separates. An all-in-one mix is simple: one scoop, one bottle, done. The trade-off is a fixed ratio - drink more for sodium and you also get more carbs and fluid. Separates (a carb-only mix plus electrolytes) take more planning but let you change one dial without moving the others.

Concentration matters. Isotonic mixes (6-8g carbs per 100ml) empty from the stomach quickly.⁶ Stronger, hypertonic mixes carry more carbs per bottle but can slow fluid delivery unless you also drink plain water. ⁶˒⁷. Read more in Isotonic vs Hypertonic Drink Mix Explained.

How To Build Your Stack

1. Set your hourly targets. Work out your carbs per hour with our carb calculator, then add a sodium and fluid target. Start with 300-600mg sodium and 400-800ml fluid per hour, and adjust if you're a salty or heavy sweater.⁴˒⁵

2. Pick your base. This is the product you take most steadily - usually a bottle on the bike or a soft flask or aid-station drinks on the run.

3. Count what your base delivers. Multiply the label numbers by how much you'll actually drink in an hour, not by the serve size.

4. Fill the carb gap. Add gels, chews or bars to close the gap to your carb target.

5. Fill the sodium gap. Add an electrolyte tab, capsule or low-carb electrolyte mix if your base falls short.

6. Total it up. Add carbs, sodium and fluid from every product, including sodium and caffeine in your gels. Then rehearse it in training.⁸

Worked example 1: separates

A 3-hour ride targeting about 85 g carbs, 600 mg sodium and 750 ml fluid per hour.

Worked example 2: all-in-one

The same target using a high-carb all-in-one such as Maurten Drink Mix 320, which gives 80 g carbs and 245 mg sodium per 500 ml.

The all-in-one does most of the carb work in one bottle. The extra water and capsule fix what its fixed ratio leaves short - fluid and sodium. Product sodium values vary, so always check your own labels.

Stacks By Sport

The best stack depends on how easily you can carry and drink fluid. Use these as starting points.

Runners

• Gels are usually your base. Carrying fluid is harder on the run, so most runners get their carbs from gels and their fluid from aid stations or a soft flask.

• Check what the course offers. Find out which drink is on course and how much carbs and sodium it has. If you haven't trained with it, carry your own.

• Don't make your flask too strong. A concentrated mix plus gels can sit heavy when you're jostled with every stride. Keep a flask near isotonic, or carry plain water alongside.⁶

• Add sodium for heat or long days. In a hot marathon or a 4+ hour finish, a capsule or tab each hour helps cover sweat losses.³

Cyclists

• Make the bottle your base. You can sip on the bike without jostling, so drink mix can carry most of your carbs and all of your fluid.

• Start light, then step up. Begin with an isotonic bottle for the first 60-90 minutes, then move to a stronger mix once you've settled.

• Use gels for timed hits. Take one before a climb, a hard effort or when your bottle runs dry. See Gels vs Drink Mix for Cycling.

• Carry sodium separately on long rides. If your carb mix is low in sodium, add a tab to one bottle or carry capsules. That way you can drink to thirst without losing your sodium.

Triathletes

• Bank carbs on the bike. It's easier on the gut than running, so front-load your stack there with a high-carb bottle and gels.

• Plan the switch to the run. On the run, move to gels plus course drinks, and drop your carbs per hour slightly if your gut is struggling.

• Split carbs and sodium after about 4 hours. In an Ironman, dilute your carb mix late in the race for gut comfort, but keep sodium steady with capsules or an electrolyte-only mix.⁹ See How Your Drink Mix Strategy Should Change During A 4+ Hour Race.

• Practise every transition. Rehearse your full race-day stack in long bricks, not just your bike bottles.

Common Stacking Mistakes

• Double-counting carbs. A strong drink mix plus a gel every 20 minutes can push you well past 90g/h. Above that, extra benefit is unproven for most athletes and gut issues become more likely.¹

• Forgetting the sodium in gels and drinks. Some gels carry 100-200mg of sodium each. Add it up before you reach for salt capsules.

• Stacking too much sodium. More isn't always better. Taking in far more than you lose can upset your gut, and there's little evidence that exactly matching losses improves performance.⁴

• Overdrinking on long days. Drinking well beyond sweat losses is the main cause of exercise-associated hyponatraemia (low blood sodium). Sodium helps, but it can't prevent it if you drink too much.⁹

• Mixing gels with a hypertonic bottle. A concentrated mix plus a gel and no plain water can slow gastric emptying and leave you bloated.⁶˒⁷ Take gels with water.

• Using glucose-only products at high rates. Above about 60g/h, choose products that combine glucose (or maltodextrin) and fructose.¹

• Doubling up on caffeine. Caffeinated gels, drink mixes and pre-race products all add up. Most research benefit sits around 3-6mg per kg of body weight.¹⁰

• Changing your stack on race day. Your gut adapts to what it's trained with. Build up your carbs per hour over weeks, not on the start line.⁸

FAQs

Do I need to stack if I'm using an all-in-one mix? Not always. For many races under 2-3 hours, one all-in-one bottle covers carbs, sodium and fluid. Stack when you need more carbs, more sodium or more fluid than its ratio gives you.

Can I put electrolyte tabs in my carb drink mix? Yes - it's one of the easiest ways to add sodium. Check whether the tab has its own carbs and add those to your total. The exception is Maurten Drink Mix: don't add tabs, powders or other products to the bottle, as they can interfere with its hydrogel technology. Take extra sodium separately instead, as a capsule or in a second bottle of water.

How do I know if I need extra sodium? White salt marks on your kit, salty-tasting sweat or stinging eyes are good signs you're a salty sweater.³ See Are You A Salty Sweater? for a self-check.

Do I need to stack for a 10 km or a short ride? Usually not. Under about 75-90 minutes, water or a light isotonic drink is plenty.²

Should my stack change during an Ironman or ultra? Yes. Many athletes do best with more carbs early, then a weaker carb mix later, while keeping sodium steady.⁹

Ready To Build Your Stack?

Start with the Aid Station carb calculator to set your carbs-per-hour target, then use the steps above to layer in sodium and fluid. Still unsure? Chat to our team - we're happy to help you build a stack for your next race.

Ash Miller
Dietitian and Nutritionist (Masters)
Bachelor of Physical and Health Education
Instagram: @ashthomo_nutrition

References

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2. Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine joint position statement: nutrition and athletic performance. Med Sci Sports Exerc. 2016;48(3):543–68.

3. Baker LB. Sweating rate and sweat sodium concentration in athletes: a review of methodology and intra/interindividual variability. Sports Med. 2017;47(Suppl 1):111–28.

4. McCubbin AJ. Modelling sodium requirements of athletes across a variety of exercise scenarios – identifying when to test and target, or season to taste. Eur J Sport Sci. 2023;23(6):992–1000.

5. American College of Sports Medicine; Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand: exercise and fluid replacement. Med Sci Sports Exerc. 2007;39(2):377–90.

6. Vist GE, Maughan RJ. The effect of osmolality and carbohydrate content on the rate of gastric emptying of liquids in man. J Physiol. 1995;486(Pt 2):523–31.

7. Rowlands DS, Kopetschny BH, Badenhorst CE. The hydrating effects of hypertonic, isotonic and hypotonic sports drinks and waters on central hydration during continuous exercise: a systematic meta-analysis and perspective. Sports Med. 2022;52(2):349–75.

8. Jeukendrup AE. Training the gut for athletes. Sports Med. 2017;47(Suppl 1):101–10.

9. Hew-Butler T, Rosner MH, Fowkes-Godek S, Dugas JP, Hoffman MD, Lewis DP, et al. Statement of the 3rd International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clin J Sport Med. 2015;25(4):303–20.

10. Guest NS, VanDusseldorp TA, Nelson MT, Grgic J, Schoenfeld BJ, Jenkins NDM, et al. International Society of Sports Nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18(1):1.
    
    

Disclaimer:
The content in this article is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment. Always speak with your doctor or allied health team before changing your diet, exercise, or taking supplements, especially if you have a health condition or take medication. Please use this information as a guide only. Aid Station doesn't take responsibility for individual outcomes.