What's in My Bidon

I want to create my own sugar mix for cycling. I have jotted down the steps towards my practical mixture. I am fine with not reaching the last marginal nutritional performance. It's mostly about not bonking and having a nice long ride.

Sugars

Sucrose (Household Sugar)

Contains 50% Glucose, 50% Fructose, so it feeds two absorption pathways at once (see below).

Very sweet, getting excessive over a long ride, and harder on the stomach in high concentrations.

Maltodextrin

A glucose polymer. That means multiple glucose units bundled into one large molecule.

Its edge is low osmolality. How heavy a drink sits in the stomach scales with the number of dissolved molecules, not their mass. One maltodextrin chain is a single molecule, so gram for gram it puts far fewer particles into solution than household sugar.

It digests quickly back to glucose and is near tasteless. This is not a regular household item, but required for a semi-performant energy drink.

Dextrose (Pure Glucose)

Single-sugar molecule (monosaccharide). Covered with Household Sugar. Is there a downside to having Fructose in the mix? The opposite, two digestive pathways make it easier to absorb. Buying Dextrose would allow tweaking the ratio, but I don't want/need to go down that deeply.

Isomaltulose

Same Glucose-Fructose content as Sucrose, but with a much more resistant chemical bond. It breaks down slowly in the digestive system and releases energy over an accordingly longer time period. Regular sipping of Sucrose mimics the same effect, and unlike Isomaltulose it can also be gulped for a faster energy hit. Isomaltulose is maybe interesting if you want to minimize sugar spikes (diabetes) and is substantially less risky for the teeth. I don't see a strict need for it for now.

Digestive Transporters

The intake rate is limited by the saturation point of intestinal transporters. They can both be trained. Activating both is generally a smart approach.

Fructose activates GLUT5 and has an absorption cap of ~30-40g/h. Glucose / Malto activates SGLT1 with an absorption cap of ~60g/h.

With my target of consuming roughly 75g/h we need a mixture of the two. A 2:1 Glucose:Fructose Ratio is chosen. I am aware that this is not the absolute performance optimum, but it seems like a highly practical spot. Still better than what professional cyclists consumed just 20 years ago.

Additives & Flavor

Citric Acid Powder

Helps combat the sweetness and the mental fatigue of it. Use food-grade powder, not the industrial cleaning grade.

Salt

To combat the loss in sweat.

My mixture (~1kg Batch)

• 310g Maltodextrin
• 620g Household sugar
• 15g Citric Acid Powder
• 10g Salt
• Optional Flavor (can also be liquid at the end of the mix. grapefruit juice)

Reaching a 2:1 Glucose:Fructose ratio.

Dosing

With my bottle size fixed, I just vary how much powder I fill in. The longer the ride, the thicker the syrup.

The mix is ~97% carbohydrate by weight, so the powder mass is basically the carbs.

Expected ride	Powder into the bottle
1 h	~75g
2 h	~150g
3+ h	~200g + other fueling

I find it hard to dissolve over 200g within a bidon. For longer rides I either:

• take a sachet of mix with me and refill later
• fuel differently (coffee breaks, proper lunch, gummy bears)

Practical Preparation

Mix it once in advance and scoop out on demand.

• Storage in large airtight container
• Moisture control with 2-3 food-safe silica gel packets in jar
• Fight separation: the sugar granules are much larger than the other powders and settle over time. Shake the canister before each use.

Dental Health

The combination of simple sugars and citric acid is a risky thing for the teeth. Combat it by having a secondary bidon with water. Use it for a quick rinse after each sugar-sip. Also, don't immediately brush your teeth after consuming something acid.