Resources
Guides and reference material to go with the calculators. Starting with how to fuel long runs and races without spending a fortune on brand-name gels.
Homemade Fueling Recipes
Commercial gels and drink mixes work well — and cost a fortune. A single marathon build can run well over $100 in fuel. The trick most sub-elites use: bulk maltodextrin and fructose cost only a few dollars a kilogram, and you can blend them to match the carbohydrate profile of premium products for a fraction of the price.
The science behind all of these: your gut absorbs glucose and fructose through different transporters, so blending them (roughly a 1.2 : 1 ratio of maltodextrin to fructose here) lets you take in more carbohydrate per hour — research supports 60–90 g/hr for long efforts — with less GI distress than glucose alone.
Pair these with the Marathon Fueling Calculator to work out how many grams per hour you need, then scale a recipe to match.
1. Maurten 320 copycat — drink mix
Maurten's Drink Mix 320 delivers 80 g of carbohydrate per 500 mL. The homemade equivalent — mix one serving into 500 mL of water:
| Ingredient | Single serving (80 g carbs) | 10× batch |
|---|---|---|
| Maltodextrin | 44 g | 440 g |
| Fructose | 36 g | 360 g |
| Sodium alginate | 1.2 g | 12 g |
| Slow-set HM pectin | 1.5 g | 15 g |
| Sodium bicarbonate | 0.22 g | 2.2 g |
| Sea salt (optional) | ~1.5 g | 10× your dose |
The optional ~1.5 g of sea salt adds roughly 550–600 mg of sodium per serving — use more or less to taste. In the 10× batch, each ~83 g scoop of mix is one 80 g-carb serving. The sodium alginate and slow-set HM pectin are what give it the Maurten-style hydrogel texture (and the pectin matters for bicarb — see below).
2. Turning it into a gel
Rather than drinking it, you can carry the mix as a concentrated gel in a soft flask (HydraPak-style flasks work far better than old baby-food pouches). Rule of thumb:
- 60% carb mix / 40% water by weight — e.g. a 100 g gel = 60 g mix + 40 g water
- In a 150 mL soft flask, about 100 g of mix topped up with water fits nicely
- Let it sit a while so everything dissolves. It comes out thick — use less mix and more water if you want it thinner.
3. Electrolyte mix
Kept separate from the carbs (easier to dose independently). A 100-serving batch:
| Ingredient | 100-serving batch |
|---|---|
| Magnesium sulfate | 25 g |
| Calcium carbonate | 8 g |
| Morton Lite Salt | 80 g |
| Sodium citrate | 367 g |
Use roughly 1.5–2 g of this mix per 500 mL bottle. Per gram it works out to about 208 mg sodium, 42 mg potassium, 10 mg calcium, and 10 mg magnesium — so a full 4.8 g serving delivers roughly 1 g of sodium (~1,000 mg), 200 mg potassium, 50 mg calcium, and 50 mg magnesium.
Note: the source prints "100 mg sodium per serving," but that appears to be a typo — working back from the ingredient weights (and cross-checking against the potassium figures, which match exactly), a serving really provides about 1 g. Sodium content is still approximate, so dial it to your own sweat rate rather than treating any number as exact.
4. Solid carb — Rice Krispie treats
For long runs where you'd rather chew something than choke down another gel: 3 Rice Krispie treats ≈ 50 g of carbohydrate (about 17 g each). Cheap, portable, and easy on the stomach. The source author also eats these as the pre-workout food before taking bicarb (below).
5. Bicarb — sodium bicarbonate
Sodium bicarbonate buffers the acid build-up of hard efforts and is delivered here inside a protective carb gel. Carb base:
- 50–60 g of the Maurten 320 copycat mix (from recipe 1)
- 1.5 g xanthan gum
- 3× water by weight of the mix — e.g. 50 g mix → 150 mL water
- Use warm water, shake well, and let it settle. Making it the night before lets everything fully hydrate.
The bicarb itself: 325 mg (5-grain) tablets are cheap in bulk. Dose depends on your body weight — Maurten and Bicarb.Shop both have dosing calculators. Common reference points from the source:
- 15 g — a common starting point
- 19 g — the author's dose (~50 tablets)
- up to 22 g — the higher end some people use
How to take it: weigh out your dose, mix the tablets into the gel so they're coated, and swallow — do not chew. Eat food beforehand. Maurten's guidance is food ~60 min before, then bicarb 90–120 min before the effort. (The author's early-morning workaround: wake up, eat 3 Rice Krispie treats, take the bicarb, then get dressed and warm up — which lands in roughly the 60–90 min window.) Dial in the logistics in training, not on race day.
Source & credit
These recipes are adapted from the "Homemade fueling and bicarb" guide on r/AdvancedRunning. Full credit to the original author — head there for the complete write-up and discussion.
This page is general information for healthy adult runners, not medical or nutritional advice. Homemade fuel and supplements — bicarb especially — affect people differently; test everything in training and consult a professional if you have any health conditions.