Dave's Rocket Fuel
I go through kilos of endurance fuel per month, and I didn’t like paying the price of a studio apartment rental just to fuel my activities. How hard could it be to just make my own fuel from scratch? All of my friends have been asking for the recipe (or just for a batch) so here you go!
A mylar bag with 2160 g of fuel
What’s in it?
A 2:1 mix of maltodextrin & fructose, plus lots of electrolytes, and a bit of lemon-lime flavour. Here’s how a single 2160 g batch breaks down:
- 1360g maltodextrin — a simple starch with very low osmolality. The primary carbohydrate in most high quality endurance fuels/gels/blocks/etc.
- 680g fructose — to utilize the separate fructose energy pathway in your gut
- 40g sodium chloride — regular table salt
- 40g sodium citrate — to increase the sodium to chloride ratio so you aren’t shoving so much chlorine into your system
- 21g potassium citrate — a stable form of potassium
- 10g True Lemon
- 10g True Lime
I sell pre-mixed batches at cost to friends, family, and LapDogs members ONLY. Send me an email or message me on Facebook if you want some. Current price is $22.22 per batch with a BYO container, or $30 in a 2 gallon mylar bag with a big desiccant pack.
Usage
First, to cover my ass: use at your own risk! What works for me may not work for you. If you are diabetic, you should definitely not be pumping loads of high-GI carbs into your system. Talk to your doctor etc. And remember: nothing new on race day.
2-ish hours or less: you don’t really need fuel
- Your body has plenty of energy on board for shorter (sub-1500 Cal) events, and you can make up the loss with a normal diet before and after the event. Just keep hydrated. You can use a small amount of mix for flavour and electrolytes, but you don’t really need it unless you are doing several back-to-back short efforts (like laps on a team).
2+ hours at 200w endurance pace
- Minimum 80g (304 Cal) of mix per hour
- Minimum 692 ml of water for an isotonic (easily digestible) solution
- Including your body’s glycogen and fat, you can go about 15 hours before exhaustion
2+ hours at 280w race pace
- Maximum 110g (418 Cal) of mix per hour
- Minimum 951 ml of water for an isotonic (digestible) solution
- Including your body’s glycogen and fat, you can go about 5.6 hours before exhaustion. Even longer if you carb load before the race.
Your rested body has about 1500-2000 Calories of easy-access energy on board (glycogen stores in your muscles and liver). You only need extra fuel if you are burning more than 1500 Calories. Your body can also metabolize approx. 300 Calories/hr from your fat reserves. If you are pushing 83 watts (300/3.6), you could theoretically go forever on fat alone without any extra fuel.
Example: 8-hour race
- Minimum 80g (304 Cal) to maximum 110g (418 Cal) of mix per hour, every hour
- Drink your first hour of fuel 30 minutes before race start
- Aim for 1 litre of water per hour for hydration. Consider a Camelbak if it’s not practical to drink that much from a bottle (i.e. MTB race).
- At an absolute minimum, you need 8.65 g (or ml, same thing) of water per gram of mix. Any less and the mix will stay in your stomach until your body dilutes it.
- The more full your stomach, the faster it will empty (assuming what’s in your stomach is diluted enough to be isotonic in your gut)
- Assuming 1500 Cal of muscle and liver glycogen + 300 Cal of fat metabolized per hour + 100g of mix per hour, you can burn 6540 Cal over 8 hours = 818 Cal/hr burn rate. Divide by 818 by 3.6 = 227 watts steady for 8 hours.
- No additional fuel recommended — your gut’s energy transporters will already be saturated, and any protein or fat will slow the rate of digestion. On very long events I may eat a slice of multigrain bread every couple of hours just to have something different and solid.
- From my experience, the longer the event, the better the rocket fuel tastes. Your body is craving exactly what it provides.
I want even more energy during a race. What can I do?
Try carb loading for 2-3 days prior to the race. Oatmeal with maple syrup, toast with jam (no peanut butter), apple sauce, fruit juice, or pasta with a small amount of sauce for flavour are all excellent high carb/low fat options. Basically as much as you can shove in as possible. Big carb meals breakfast, lunch, and dinner. Your last huge meal should be the lunch before race day. Have a normal size dinner the night before. And get lots of sleep!
I’m thinking of making an even more potent mix (Ultra Fuel?) using Cluster Dextrin instead of maltodextrin (like Skratch Superfuel ). Cluster Dextrin is much more expensive though ($30/kg instead of $5.40/kg), so it would be a race day only fuel.
How does it compare to other endurance fuels like Gatorade, Hammer’s Heed, Maurten 320, etc.?
Basically the same or much better than any other endurance fuel at a tiny fraction of the cost. I based the recipe on Maurten 320, information gleaned from the fantastic TrainerRoad podcast , and a shit-ton of additional research. The goal was to ingest the maximum amount of usable carbohydrates per hour for many hours in a row (up to 24 hours steady) at a reasonable price.
| Mix | $/100 g | Max Cal/hr |
|---|---|---|
| Dave’s Rocket Fuel | $1.19 | 418 |
| Gatorade powder | $2.29 | 80 |
| Hammer Heed | $3.32 | 110 |
| Maurten 320 | $6.07 | 320 |
Cheaper “fuels” like Gatorade use table sugar (sucrose) at very low energy density. Look at the label — 80 Calories per bottle? That’s nothing! You could never drink enough to come close to maxing out your gut’s energy pathways. What about using 100g of Gatorade powder in a bottle? No dice. Sucrose has a much higher osmolality than maltodextrin, so you need to consume much more water to digest the same number of calories — more than you could realistically drink hour after hour. Without dilution Gatorade will sit in your stomach while your body slowly dilutes it to an isotonic solution (temporarily dehydrating you from the inside). You’ll get very full very fast with hardly any grams of carbs per hour.
Hammer prides themselves on not including any “-ose” ingredients in their fuel. This is very outdated thinking and ignores the recent science around adding fructose to energy drinks. Your gut has separate energy pathways for glucose (SGLT-1 — maltodextrin is just a short chain of glucose molecules) and fructose (GLUT-5), and by leaving fructose out of a recipe you are completely ignoring an entire available energy transport system in your gut. Fructose is much more expensive than maltodextrin, so…I guess their profits can be higher? In my experience, more fuel = better performance.