Educate me on sugars

Currently there is a lot of talk on the necessities of fuelling workouts and a trend to mixing your own homegrown energy drinks.
I’m currently trying to better understand the different types of sugars and how they best work together; fructose, glucose, maltodextrin.

Fructose goes to the liver, so takes longer before you can access the energy.

Glucose is metabolised and accessed faster and easier; can be stored as glycogen.

(Sucrose is glu + fru 50/50…table sugar.)

Malto is a starch & processed as fast as glucose but is less sweet.

Your body can upload both glucose & fructose so you want some combo of each to get max fuelling.


Simple homemade mix here.

I just add maltodextrin to an existing energy drink. It’s a lot easier to get the taste right.

Thanks for the responses. So in essence fructose and glucose can be sourced as natural sugars but maltodextrin is processed?
I’m guessing that is why I found a couple of “is maltodextrin harmful?” articles when looking.

Uh, no – all three are natural (whatever that means) and all three will always be processed.

edit: a short list of “processed”/manufactured “sugars”/sweeteners:

sucralose, aspartame, saccharin, sorbitol.

A 2:1 glucose/fructose ratio is only ideal for maximising carb intake. If you’re only doing an hour and only want to supplement with 40-60g of carbs, there’s no need to utilise fructose (for the reasons Doughnutman listed above, plus it’s more expensive). Please do the research yourself and figure out what’s right for you and your circumstances.

Also maltodextrin = glucose isn’t quite right. Without going into loads of detail, Malto is a longer chain sugar, so takes a short while to break down for your body to be able to uptake the glucose. It’s good for fuelling exercise because it’ll give you a fairly quick steady ‘flow’. Dextrose can be absorbed faster, and will probably spike blood sugar levels more. Maybe good for a quick hit between hard intervals?

It’s all processed - and as long as you use them appropriately I can’t see it being harmful. Honey is natural if you pay enough for it, but if you go to extremes and eat a whole jar at a time, then that would probably be pretty darn harmful.


Thanks for the info @Captain_Doughnutman and @4ibanez, needed to deepen my knowledge. My comment on natural was meant in terms of something like a banana or date. Presumably that will contain fructose and glucose but not maltodextrin.

@rkoswald I’ve been messing about with a similar recipe, just got sidetracked by a recent comment on natural fuelling and wondered how it all fits together.

Note that in this context “natural” is actually not what you want. “Natural” Whole Foods contain also a lot of fiber which slows down the absorption rate of the carbs. On the bike you want simple carbs that can be taken in quickly. And this stuff is only for energy so the absence of other nutrients is no big deal.


Read the wikipedia article on maltodextrin for a fuller explanation of what it is. I think that will help you understand it better.

Might be helpful to think of maltodextrin in the same category as flour. Basically just broken down/partially digested plant material.

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No refined sugar is unprocessed, but maltodextrin absolutely appears naturally.

Starch is a long chain of glucoses. The dextrins are medium-size chains of glucose. If you cleave apart starch, you’ll get shorter-chain sugars. Anything that can digest starch does that. Beer, for example, will contain maltodextrin because it’s produced in the malting and mashing stages but can’t be digested by yeast.

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See my comments throughout: