Performance Nutrition, Sweat Sodium And The Secret Hydration Formula Of The World’s Top Endurance Athletes.

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Click here for the full written transcript of this podcast episode.

In my article The Real Truth About What To Eat Before, During And After Your Workouts & Races, I mentioned a guy named Dr. Allen Lim, and I specifically gave a shout-out to the recipes he invented when Lim was director of sport science for Garmin and RadioShack cycling teams. 

In that article, I talked about recipes like Chocolate & Sea Salt Sticky Bites, Blueberry & Chocolate Coconut Rice Cakes and Crispy Rice Omelets. You can't argue that those don't sound tasty (and yes, when you eat them with coconut oil you can still be in ketosis, you high-fat zealot, you).

Anyways, the photo above was taken a few weeks ago at my Team Timex triathlon camp, during which Lim conducted a cutting-edge sweat sodium analysis on me (which we discuss along with many other nerdy nutrition topics in this podcast episode).

Lim is a sports physiologist, cycling coach, and a founder of Skratch Labs, a manufacturer of performance hydration mixes and the world’s first active nourishment company. Beginning his coaching career with Jonathan Vaughters’ TIAA-CREF cycling development team, Lim developed a method of testing for biological markers of performance enhancing drugs that ultimately led to cycling’s Biological Passport.

Lim was director of sport science for Garmin and RadioShack cycling teams and is the only American scientist to have worked and cooked for teams at the Tour de France. He has not only worked with dozens of top American cyclists to improve their performance and nutrition, but has also worked with guys like Lance Armstrong and George Bush .

Along with Chef Biju Thomas, Lim is also the author of The Feed Zone Cookbook and Feed Zone Portables.

In this episode, you'll discover:

-Why popular sports drinks are mixed in the wrong concentrations, and how this leads to something called “gut rot”…

-Why you may need to add sushi rice to your race day or long workout protocol…

-The physiological reason why “cane sugar” is absorbed so well during exercise…

-Why Allen isn't a fan of stevia…

-How MCT oil and coconut oil could actually speed up gastric emptying (and why that may not be good!)…

-Allen's thoughts on Jeff Volek’s research on fat utilization during exercise and the apparent need for fewer carbs in fat-adapted athletes…

-Allen's thoughts on Tim Noakes’ idea that based on our electrolyte stores and the fact that sodium loss drives sodium extortion that electrolyte intake is useless during exercise…

-How to create a customized sodium and hydration replacement scenario based on your unique sweat sodium loss…

Resources we discuss in this episode:

The infamous “egg-hydration” video

The Feed Zone Cookbook

Feed Zone Portables

Skratch Labs

Stryd power meter for running

Do you have questions, comments or feedback about Allen Lim, Skratch labs, sweat sodium, sports nutrition or anything else we talk about in this episode? Leave your thoughts below!

Ask Ben a Podcast Question

13 thoughts on “Performance Nutrition, Sweat Sodium And The Secret Hydration Formula Of The World’s Top Endurance Athletes.

  1. boredyak says:

    No mention of protein or amino acids. How do they fit into the equation? I've read that inclusion of them into the intra-workout mix can preserve muscle tissue.

    1. Yes, I do indeed recommend adding either aminos capsules or aminos powder at a rate of 5-10g/hr during hard workouts. Allen doesn't really implement that, but I've found it to be a game changer. For my fav brands, do a search for "aminos" at

  2. joelg1 says:

    Ben, love your podcast and this episode. There was a lot of great discussion regarding osmolality of sports drinks and optimizing the concentration of the salt and carbohydrates in the drink to maximize transfer to the body. Then, at the end of the podcast, there was a brief discussion of adding whole food, like Lim's delicious portables, to the mixture in your gut. What effect does adding whole foods have on osmotic pressure and hydration? If you use whole foods, should you drink plan water or drinks with lower osmolality?

  3. Sorry for the delay! Here is Dr. Lim's response:

    Yes, sweat sodium concentration does depend on sweat rate. At higher sweat rates more sodium is lost and then at lower sweat rates. We are still in the midst of completing a study looking at sweat sodium concentration induced with pilocarpine versus exercise. So far, sweat sodium concentration from pilocarpine seems to approximate the sweat sodium concentration induced by hard to very hard exercise or the high side of sweat rate. What is clear is that pilocarpine seems to be a great way of distinguishing general sodium sweat loss between individuals as the location and dosage is constant, whereas, sweat rate and exercise intensity are not consistent between individuals even in similar environments because of large differences in body surface area to mass ratios and heat load. Ultimately, I believe the macroduct system for collecting and assessing sweat sodium is the best system currently available, especially, to understand a general category of sweat sodium that a person might fall into. It is, however, by no means perfect and much more work and measures are required to really describe someone's sweat sodium loss over a wide array of heat loads and exercise intensities. That said, it's a great start to begin measuring something that is typically never measured and as this type of technology improves, I'm sure that we'll continue to learn more. Until then, like all things, listening to our bodies and using common sense is always important as is using data to begin to understand our personal performance.

    White streaks or deposits are not necessarily an indication of the actual sweat sodium concentration. For example, someone with a high sweat sodium concentration but a very low sweat rate might lose exactly as much sodium as someone with a very low sweat sodium concentration but a very high sweat rate. In addition, whether or not sodium accumulates and is visible on a fabric also depends on the total duration of exercise and the type of fabric used. Many companies go to great lengths to find fabrics and dyes that do not show white deposits during exercise as it's considered unattractive to consumers to see white deposits on their clothing.

  4. wackerb says:

    2 questions:
    Dr Lim mentions in passing that just sitting around sweat has a lower sodium level. That would seem to imply that sodium concentration depends on how hard you are sweating so the drug induced test may be great for standardizing based on drug dosage, but there could be a big difference in reality. I'm thinking racing under relatively cool conditions versus full on tropical heat and moisture. Is there any data on that?

    Second, at the end of your test you answered some questions for his correlation data. Did you get the outcome of that? Subquestion: If you're a high sodium sweater how come no white deposits?

  5. n = CK says:

    What a great interview with a ton of information! However, I was left a bit confused about the role of sushi rice to fuel performance. You seemed excited to bring it up, but then it was glossed over with Dr .Lim saying it all breaks down into glucose. How does this fit into the protocol? Also, doesn't some of the glucose in sushi rice convert to resistant starch? And doesn't the vinegar reduce some of the glucose response?

    Any clarification would be much appreciated. I love me some sushi rice!

    1. Dr. Lim just got back to me with this response:

      Most complex carbohydrates and starches like rice, potatoes, and pasta all break down into simple glucose when digested. So real food like rice fits into any nutrition program as any food or carbohydrate supplement might. The real difference is that whole food unlike carbohydrate supplements also contains fiber and thus requires longer for digestion in the stomach. Thus, sushi rice tends to have a lower glycemic index than pure sugar or maltodextrin, but being fairly processed still has a higher glycemic index than brown rice or other unprocessed starches.

      Almost all of the calories or sugar from rice is absorbed by the small intestine unless there is some secondary issue causing gastrointestinal distress or damage to the intestinal wall that prevents the absorption of glucose. So as far as I know, sushi rice does not convert into a resistant starch that bypasses absorption, moving through the bowels like a indigestible fiber would. That said, there is still fiber in rice so some waste will be produced.

      Regarding vinegar and glucose, acetic acid or acetate from vinegar, has been shown to increase the rates of glycogen re-synthesis in the liver and skeletal muscle when both acetate and glucose are ingested together post exercise.

      Ultimately, mind your calories and eat what you like. The details beyond that probably aren't that important.

      1. n = CK says:

        Thanks for following up on this! It just sounded like there was something extra-special about sushi rice that is not well known, but it seems like it's par for the course.

  6. Peter says:

    Very interesting. A few comments

    Why no discussion of UCAN starch?

    I was very surprised that his only criticism of maltodextrin is taste. Stacy Sims has a lot of negative things to say about it.

    lim doesn’t treat Noakes fairly. He sets him up as a straw man

    Lim’s product and approach seems better suited to stage racers (how many of us do 21 stage events)? Where sodium depletion can happen and where gut problems from daily sugar ingestion are likely to snowball.

  7. gassaned says:

    Hi Ben, if my English is weird its because Spanish is my native. What a great post, but i still believe on Tim Noakes approach, i mean i am not an expert at all, but wouldn´t i replenish my sodium stores after training or racing as well as we do with glycogen from foods and so?? .And during exersice would not my body selfcontrol sodium deficit without losing a bit on performance as Dr Tim Noakes and so other studies shows? i get the individuality of sodium lost and how for me 3% of BW lost could represent massive sodium while someone else might loose 7% with the same sodium lost. With all respect i do not think Allen is totally informed on Tim Noakes Studies about hydration or hyponatremia, its way more there on sport related than just human beings surviving to dehydration. its a very cool debate, you should podcast both of them in a row jejej. Thank you for so interesting information, and it makes a lot of sense if we approach to think that maybe lost in performance goes not with dehydration but sodium depletion.

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