We approach our rides very similarly. 
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Your App sounds interesting. and I look forward to seeing it in the Play store.
Over the years I have tried every type of fueling strategy but over the last three years rely almost totally on maltodextrin or a maltodextrin and fructose mix in a 2:1 ratio. I find the 1:0.8 ratio too sweet.
I rarely fuel indoor workouts unless they are extremely intense or I havenāt eaten much beforehand, then I might put 30g malto in 500mls water.
Rides of 2 to 4 hours are around 60g per hour, 4 to 6 hour rides around 100g per hour and for 6 to 8+ hour rides I focus on getting in 120g per hour. If I do this the effect is profound with little to no difference in my 4, 5, 6, 7 and 8 hour power.
While I have no problem with stomach issues tonicity can be an issue. There are no shops on my routes and I filter water from a limited number of streams and other natural sources. I carry two 750ml bottles and all the mix I need for the ride. If the weather is warmer than normal or the effort is intense then I really need extra plain water or electrolyte mix.
My last HbA1C was 5% so no warning signs there.
Despite doing this for years, and having a spreadsheet! there are always some back-of-the-napkin calculations before a long ride so I can see where an App would come in handy, best of luck with it.
Yeah, fructose is pretty darn sweet! Sometimes if you add sodium (NaCl or NaCitrate) it can combat that.
Super cool.
Wow. I feel you there. Iād go through that fluid in under an hour sometimes.
Iām having a gout attack now and am wondering if fructose is playing a role. I recently started experimenting with 66/33 grams per hour glucose fructose and had to cut a 4hr ride short 2 hours in, but was fueling for it to be a longer ride. The next day i started feeling the classic toe stiffness and since itās been torture to jam my foot into cleats. Maybe i should add that i had a very intense day (400 for 35mins) the day before because earlier in the thread someone mentioned that exercise can temporarily bump UA levels.
I donāt have a ton of the classic life style links (27, donāt drink, vegan, bike at least 10hrs a week, only slightly overweight- 200lbs at 6ā2") but my dad has had it in the past so that probably plays a role. I only ask about fructose because itās a recent change Iāve made and I havenāt had any gout in over a year before this.
I have very little knowledge on these issues and had a few questions for those in the know or people who have experienced gout:
Iām curious if anyone is aware of any difference between pure fructose and say maltodextrin for uric acid levels?
Does it make sense to fuel with only glucose on easier rides, if so how high can i take that?
Should i stop fueling say, 15-30 minutes before my ride is over to give my body a chance to clear the blood sugar?
Any experience or knowledge would be greatly appreciated, thanks!
I havenāt seen anything regarding endurance athletes and uric acid after fructose ingestion. The Peter Attia Podcast with Dr. Richard Johnson was a real eye-opener regarding the evils of fructose ingestion. Uric acid in the cell can screw up mitochondrial function. Personally, I have avoided fructose given that the downside is so severe. Fortunately due to age, being slow and a low FTP, my carbohydrate requirements are much less than someone who can push out 400 watts for 30 min.
Thanks for the LOLs.
RE the whole fueling strategy in general, I feel like there needs to be the caveat of āIf Z2>200 watts then CHO = 60-80 g/hr. If Z2<150 watts we are in a lot lower CHO demandā
| Power | HRs | Kcal | |
|---|---|---|---|
| 250 | 2 | 3.6 | 1800 |
| 225 | 2 | 3.6 | 1620 |
| 200 | 2 | 3.6 | 1440 |
| 175 | 2 | 3.6 | 1260 |
| 150 | 2 | 3.6 | 1080 |
| 125 | 2 | 3.6 | 900 |
| 100 | 2 | 3.6 | 720 |
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along with how well/poorly you are carbing off the bike. For āmoderate exerciseā I think the rule of thumb is 6g per kg, per day. For myself thats 500-600g of carbs/day and can sustain base phase riding of 10+ hours/week and 6000+kJ/week of work.
Glad you enjoyed that.
Additional caveat (because who doesnāt love caveats to caveats):
Low-fitness folks are usually burning a higher percentage of carbs as fuel than higher fitness folks, and are usually more susceptible to symptoms of hypoglycemia.
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Maybe i should rephrase my question and say that Iām concerned about fructose specifically and how it relates to uric acid levels. I donāt disagree about the general carbohydrate comments, but I think there are a lot of other threads that address that.
I canāt handle 2:1 ratioā¦ it can be ok if I have a really hard training but of not and if i take more than 20g of fructose per hour I have bloating and really really smelly fatrsā¦
Iām sorry to hear that you are having an episode of gout - I know how excruciating it can be!
In my experience, having high levels of fructose via pure fructose powder mixed with maltodextrin in a 2:1 ratio gave me gout. It was the only thing that I changed in my entire diet. I was able to take 8 bottles of the mix over 7 days and afterwards I had my gout episode. During those workouts I had during the week, the mixture had me feeling very bloated and I even gained weight and fat from it.
I asked Dr. Tim Podlogar about it after he did a guest talk on the Science of Getting Faster podcast and linked him to the study in my original post. He was quickly concerned but then replied that that uric acid levels would remain under control as long as the individual exercised. I dismissed his opinion based on the fact I was working out intensely 6 days a week on TR programs.
I since have stopped having fructose powder and havenāt had a gout episode induced by malto/fructose mixes. I did have an episode of gout after having 4 mangoes in one day, however.
Maltodextrin does not cause uric acid levels to increase. This has been my preferred fuel by necessity since I cannot mix with fructose. 60gm/hour of maltodextrin is the upper limit. Any more and you might start having gastrointestinal issues. Also be sure to keep very well hydrated. I like to chase my maltodextrin drink (which is already diluted with 650ml water) with a mouthful of water.
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Thank you so much for your reply. It sounds like avoiding fructose is a good call for people prone to gout, even if they exercise.
I havenāt seen any evidence that glucose is a problem for uric acid levels. Max glucose (to stomach tolerance) and then eliminate fructose (or manage the UA risks) sounds like the way to go.
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Thatās really interesting. I think glucose may be a manageable risk for me since I havenāt had gout problems from bike food other than adding pure fructose, but definitely something to watch out for. It does suck since thereās definitely a performance benefit to the pure carb intake, just not one that outweighs the performance downsides of not being able to put a shoe on.
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I was doing 60gm/30gm malto/fructose.