Maltodexrin bad for you? fondo onboard nutrition advice

my indoor training i fuel with baby food pouches. $1ea, 25g carbs and digest easily but im going to need at least 20 (almost 3000ml) of them to get through my fondo in september. they are also relatively difficult to open while riding outdoors with having a screw lid. ive been looking into maltodextrin but theres a lot of negative info out there. Because as cyclists, do we digest the maltodextrin quickly during hard rides?, is it less harmful as opposed to sitting on the couch consuming it as additives to our food? i have 40days until my fondo so i need to get training with whatever i’m going to be consuming during the ride. i want to stop at rest stations as little as possible so i want all my nutrition on me from the start. I want to have about 400g carbs in liquid form with 150-200g in solid food. I’ll have 2 x 600ml bottles on my bike and i can shove another down my jersey. one of them at least must be water.

i saw jesse coyle’s video where he used table sugar. i like how easy and cheap it sounds and i can start training with it right away. i could also get all my carbs into a single bottle this way. anyone have experience with this?

thank you for any advice and tips

I almost exclusively fuel with homemade energy drink. I use 70g of malto with a bit of electrolyte powder in a 500ml bottle. Usually have one bottle an hour for every ride, works great and is dirt cheap.

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There’s a pretty big thread on making your own drinks: Make SIS BETA fuel yourself just a few pence per bottle

My personal concoction is granulated sugar + neutral hydration tab + a bit of lime cordial, as means I just need to order cheap tabs every now and then, and otherwise easy to source nearly anywhere. Find it very palatable.

On health aspects, I think a lot of advice is around sedentary consumption, in which case sugars aren’t going to be great to have in quantity. Sucrose (table sugar) is definitely bad for the teeth in a way worse than other sugars though (The Role of Sucrose in Cariogenic Dental Biofilm Formation—New Insight - PMC) so I’d always rinse with fresh water after a swig. I should probably just switch to malto/fructose…


If you are taking on the nutrition on the bike, I wouldn’t worry about the carbs being “bad” for you. Personally, I use a mix of table sugar and maltodextrin to get in 90g of carbs per hour in a 2:1 glucose to fructose ratio. I use sodium citrate and table salt for electrolytes and lemon juice for flavor. This saves me a ton of money. You could just use table sugar, but I like to know that I am taking as much glucose as I can digest, and since I’m not taking 120g of carbs per hour, table sugar only doesn’t work perfectly for me. I like to put all of my carbs and electrolytes in one bottle, almost like a giant gel, and the rest of my bottles are water, but I would suggest experimenting with this type of thing because everyone has different preferences.


The last guest on Rich Rolls podcast was an expert on gut health and he talked briefly about how bad maltodextrin is for gut microbiome. It has some effect where it wipes out the good bacteria and makes everything less diverse…etc

I’ve done a few hours of googling since then, looking for specific studies, but haven’t seen anything sports specific as it relates to gut microbiome diversity and maltodextrin. It certainly seems possible that the malto is used so quickly in the stomach and small intestines that it doesn’t have time to get into the large intestines and colon and cause havoc like it might with a sedentary person. Or it may be bad for your gut, regardless of when/how it’s ingested.

I’m also not sure the alternative of straight table sugar is better or worse at it relates to gut health. Yea, it’s less processed…but I can’t imagine it’s necessarily GOOD for ideal gut health to pour a cup of pure sugar into your stomach on a daily basis.

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I chew gum during most rides with the idea that it will help my teeth when I’m essentially drinking sugar water for hours. Beyond that I’m not worried about the effects of maltodextrin and fructose during exercise.

Just try to keep in mind that nutrition advice aimed at a sedentary population is different from advice for someone that is going to burn thousands of additional calories during a +3 hour ride.


What sort of watts or speed goals are we talking about, solo ride, small group, big group? And temperature?

Typically myself going with normal or rich generic sports drink plus gels (not that often) or some easily chewable wine gums, fruit candies aso. because they generally taste much better. That nice taste adds positive vibes that mean much when you’re maybe knackered or weather sucks or both.

152km, 3300m elevation. ftp 338, 3.7w/kg, 6’4, 91kg. hoping for under 5hrs. im going to be going for best time possible for my fitness level. climbing pace looking for 80-85% ftp. 280-300w. last year i did a 162km, 2200m fondo with less fitness, no structured training and probably consumed 150-200g carbs max in whole ride. did it in 5hrs 20. looking for significant improvement this year with well structured and well fed training. looking to consume 100-120g carbs per hour plus 1g per pound before the race begins

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I’d also suggest you look at THIS THREAD, see some of the YouTube videos @Dr_Alex_Harrison and maybe try the Saturday app. Make sure you have both good fueling AND good hydration.

My contribution: there is nothing wrong with malto during exercise. Sucrose, malto, and MANY other things are bad for you in significant quantities while not exercising. But during a hard ride, it’s FUEL and will be metabolized pretty quickly so you can use that energy.


If you’re trained your gut in normal training to take in big amounts of carbs, your plan is just fine. Of course it depends too how accustomed you are rides like this (amount of climbing, duration, IF). If this fondo is regularly achievable it’s one thing energy management wise, if it’s breakthrough ride then it’s different thing. This because body may do quite a turnaround when getting deeply fatigued in acute way.

This is a great summary. ^^^

If folks want a little more info, this article provides some more detailed insight → The Risks, Harms, and Science of Sugar and Endurance Athletes -

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If the baby food pouches are meaningfully healthier for you (e.g. because of included fiber), then eating 20 of them over the course of 5 hours could give you a lot of gut distress. I think that either malto, malto+fructose, plain sugar, or malto augmenting aid-station fuel are all practical ways to fuel for the fondo.

Most fondos have aid stations with drink mix, but those drink mixes rarely have enough carbs, so if you want to fuel your ride with liquid nutrition (which is what I typically do, since I don’t enjoy gels), you can either bring all of your dry carbs with you (malto, sugar, or malto and fructose) and just get water at the aid stations, or you can bring malto and stir it into aid station drink mix to increase the carbs.

Malto has a big advantage over most other carbs in that it has almost no sweetness, so you can add it to a sports drink without it making the resulting drink too sweet. The disadvantage is that it doesn’t dissolve very well into cold liquids.

The forum threads that others cited are certainly helpful. I personally use 60 grams of maltodetrose, 30 grams of fructose, and 3/4 tsp of sodium citrate per hour, mixed into 750 ml of water. Once I’ve gone through three hours worth at a fondo or long race, then I often mix powdered malto into the aid station’s drink mix (and sometimes grab pretzels or other salty snacks as well).

I’ve been using malto for probably seven years, and I haven’t noticed GI issues that seem like would be common if it was destroying my gut flora per the video that someone cited, but who knows. I don’t eat malto when I’m off the bike, but I also limit organic sugar, tapioca syrup, fruit juice, and all other “healthy” sugars off the bike. I would guess that malto is roughly as unhealthy as table sugar, white rice, or refined white flour, but maybe I’m being naive.

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Sugar in high quantities is bad for you when sitting on the couch because of the huge insulin spikes can cause you to become insensitive to it. But during exercise, the uptake of sugar is mostly insulin free so you don’t have this negative affect.

The affect on the teeth can be real for some people. But I consume ~100g/hr for 13hr/wk on the bike with at least half coming from the bottle. I try to always take a swig of carbs and then a swig of water and I haven’t had a cavity in many years (since before I started doing this).


If it’s going to be hot I strongly recommend looking at Jesse Coyle’s other suggestion of making an ultra concentrated mix of sugar (whatever form), dissolved in hot water, then poured into re-usable gel flasks.

I can fit 500+g of sugar into my 2 250ml gel flasks using this method which gets me most of the way there, with some oat snack bars & sweets to make up any extra I might need. Pure water in your bottles is much better, especially when it’s hot.

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How do you estimate how much to drink from those gel flasks every hour?

So you basically make a simple syrup mix?

Are you adding salt to that or getting that in another way?

I now use about 100/120g maltodextrin, a good pinch of salt, agave syrup for fructose (about 50 grams ) and consistency , and the juice of half a lemon for flavour. I put that with very little water in one of those flexible 150 ml pouches and use it as a gel. Tastes better than a lot of the commercial stuff, IMO. I have there about 150 grams of sugars, it lasts me for a whole ride with hard efforts

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unless you don’t care about your teeth unequivocally yes