Metabolic Pathways

Not always an option. Especially on 15% plus climbs that last for over a mile. Trust me… I would be a above threshold if I didn’t have to do so.

I did a test. Interesting, but your microbiome changes all the time. So, unless you get a test several times a year, to see how it changes overtime with what you eat… not very helpful. And… marginally if you do test all the time. My takeaway was eat healthy and try not to each the same thing over and over again as too much of a good thing isn’t great. You gut likes variety within good healthy, high fiber foods.

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How do you achieve this without massive GI issues: gas, diarrhea, etc. post ride?

Also, how do you carry that much carbs on you? That like 6-8 bottles of carbs. Then, how to you handle hydration? SIS gels are 22g and you can take 3/hr, so 66g plus a bottle 40g. But that like 12 gels in your pocket, not to mention carb drink mix. And, that doesn’t count hydration. Just trying to figure logistics of 100+ carbs an hour.

One bottle with carbs and one with water? Carbs can be really concentrated, make small sips and flush with water. No problem with 200-300g of carbs this way.

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Optimal sugar ratios and hydration throughout. Must hydrate to meet carb consumption rates. Must consume high sodium tor retain fluids consumed and not get hyponatremic. Target 1:1 glucose:fructose. Target 800-1200mL water and 700-1500mg sodium per hour from sodium citrate, primarily.

How I do it:
Saving Money as an Endurance Athlete

Review a few of my other recent threads’ activity and you’ll see a few responses that detail much much more.

This is exactly how my wife and I do it. For her 7-hr, 140-mile ride yesterday she had 500g carbs in one bottle, 300g carbs in a second bottle, and a plain water bottle. She stopped for a water refill as soon as she finished the 300g bottle and the water bottle.

At that point she then had 500g of carbs onboard and 2 fresh bottles of water. I think that lasted her through to the end, but she’s a bit of a light sweater. If it were me, I’d have done 600 & 300, + 1 water, then stopped twice for top-ups on water.

Plain white sugar comprised ~85% of her total carbs. Gatorade was the remainder. Sodium Citrate were her electrolytes. Plus 2 caffeine tabs. One pre-ride, one mid-ride for 400mg caffeine. She weighs 63kg for reference.

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This thread is useful throuhgout. How are people getting 100g+ carbs in a bottle? - #198 by Dr_Alex_Harrison

Thank you for the tip on saving money.

Do you mix the sodium with the glucose/frutose in the same bottle.

Front bottle = carbs + sodium + water
Back bottle = water only

Needed to buy new water bottles last year and I got color coded:

  • blue top = water only
  • black top = electrolytes (if eating food) or carbs+electrolytes
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Nice! I Sharpie’d ours.

The experience with Lumen is really great, in the morning I get a suggestion about how much carbohydrates, protein and fats I should eat,
in the meantime I’ve made a set of meals to organize the things better to reach the suggestions.
If I don’t have enough carbohydrates before a workout, Lumen tells me to make improvements, I can handle hard workouts so much better!

they have a very good customer support, they contacted me, because the seen something goes wrong with my first device, they sent me a replacement very fast.

At the beginning my carb suggestions was to low and the fat to high, but they changed it in the background (Nutrition Expert Ulrike), now i eat exactly as much as i need for my workouts (Duathlon) and my body weight is very stable too and my performance increases from week to week

Very interesting . Thanks

Thanks. Just bought some sodium citrate (trisodium citrate Na3C6H5O7) and did the math using molecular weights and density. Posting for future reference:

  • 1 teaspoon = 4.93 ml
  • Sodium citrate is 1.008 g/ml
  • 4.969 grams of sodium citrate per teaspoon (4.93 x 1.008)
  • using molecular weights of sodium citrate and 3 sodium atoms, by weight the sodium is 26.7% of sodium citrate
  • 1326mg of sodium in 1 teaspoon (4.93 x 1.008 x .267)

hope that helps anyone interested. And someone correct me if my high school chemistry failed me!

This label found on Modernist Pantry:

puts Sodium at 235mg per gram of Sodium Citrate. Using 1 teaspoon = 4.969g from above, that puts sodium at 1168mg per teaspoon.

So three estimates per teaspoon:

  • 1000mg rough estimate
  • 1326mg from density and molecular weights
  • 1168mg from a label

close enough!


I’m skeptical (unless you bought the sodium citrate from their catalog) a volumetric measure for a powder is going to depend on how the crystal is formed/ground. I’m thinking of differences between brands of salt: Morton’s kosher salt vs table-salt vs diamond crystal (light and fluffy).

Anybody have access to CRC Handbook of Chemistry and Physics? I sold mine and only have the CRC Math Handbook on the shelf.

My calculation above is also off, I used molar mass of 258.06 g/mol which is true for anhydrous but I believe the correct value is 294.10 g/mol for dihydrate version of trisodium citrate. So that would change the percentage to 23.5% …

  • 1 teaspoon = 4.93 ml
  • Sodium citrate is 1.008 g/ml
  • 4.969 grams of sodium citrate per teaspoon (4.93 x 1.008)
  • using molecular weights of sodium citrate and 3 sodium atoms, by weight the sodium is 23.45% of sodium citrate (3 x 22.989 / 294.10)
  • 1165mg of sodium in 1 teaspoon (4.93 x 1.008 x .2345)

ignoring granularity for example Cargill specs 60lbs/cubic-foot for granular and 58 lbs/cubic-foot for fine granular (the stuff I bought on Amazon looks to be fine granular).

Which bringing this back full circle the three estimates per teaspoon are:

  • 1000mg rough estimate
  • 1165mg from density and molecular weights of trisodium citrate dihydrate
  • 1168mg from a label

When operating in non-medical biology, and especially with electrolytes, rough estimates will do just fine.

VERY much appreciate the lengths you went to to come up with accurate numbers.

Carbohydrate accuracy is likely to be much more important than sodium measurement accuracy, and even for carbs, I don’t sweat it. (terrible-pun intended).

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Yeah, I’m not sweating the details. Just wanted to understand where the estimates came from, and have a chance to revisit two years of high school chemistry LOL.

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PS. I’ve been waiting for the day someone calls me out on these super-round numbers I’ve been using :slight_smile:

Honestly, I’m surprised it took this long! Our resident chemical engineer, @redlude97, got close to doing so in another thread, I think.


nice! you da man

I’m a little confused about the updated calc using density of anhydrous and molecular weight of dihydrous, but I’m good with rough estimates. It’s not like I actually know my sodium loss from sweating. :wink:

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