The black magic of nutrition; it’s a mystical art. What should you eat? What should you drink? How much? When should I consume it?
Long gone are the days of factory-produced chocolate Powerbar logs and pouring salt and sugar packets in to water. We now have new high tech formulas, salt tablets, and people telling us to make sushi rice cakes. But among these new foods and ideas, what is best? How do we know? Dr. Stacy Sims has her own take on it: Put some numbers behind it. When in doubt, test, research, and test again.
So that’s what we did.
Dr. Sims is, for lack of a better title – a nutrition freak. She earned a BA from Purdue University, an MSc from Springfield College, and a doctorate from University of Otago. She was an exercise physiologist and nutrition scientist at Stanford University. If you want to get her talking, bring up thermoregulation, gastric emptying, or maximizing vasodilation and evaporative cooling (what we normal folks call ‘sweating’). On more than one occasion during our time together, I had to politely ask that she reduce her word choices from PhD… to master’s degree… an sometimes down to a 3rd grade level when I really glazed over.
You are probably familiar with Dr. Sims’ work without even realizing it. She has helped to create several existing sports nutrition products on the market, and acted as a nutrition consultant for the Garmin/Slipstream Pro Cycling Team, the USA BMX and women’s track Olympic teams, Team Tibco, Team Leopard-Trek, and many top triathletes. More recently, Dr. Sims sought to create her own nutrition company, along with two co-founders, Ben Capron (formerly of Specialized), and Paul Pillitteri. The name is simple: Osmo.
What is Osmo? To even start, you must understand that the name came from a few other words – osmosis, osmolality, and molality.
Let’s start at the beginning. First, we must understand the concept of solutes and solvents. Simply put, a solute is a substance that dissolves in a solvent. If you have a glass of water and drop in a teaspoon of sugar, the sugar is the solute and the water is the solvent. Osmosis is the movement of solvent molecules through a partially permeable membrane1. When two areas are segregated by such a semi-permeable membrane (i.e. intestinal tissue), they want to achieve equilibrium. So what happens? The solvent travels from the area of low concentration to the area of high concentration to even things out. This process works great, and is what makes the water you drink get absorbed into your body (thanks, osmosis!).
Osmolality is similar to molality, but only takes into account solutes that contribute to a solution's osmotic pressure2. Put more simply, Dr. Sims says that it’s determined by the amount of ‘active’ particles in a solution. In a sports drink, osmolality is primarily determined by the macronutrient content – carbohydrates, amino acids, and proteins – and to a lesser extent, the electrolytes and other fillers (colors, additional flavors, etc). In blood plasma, osmolality is determined by substances like sodium, potassium, chloride, bicarbonate, urea, amino acids, and glucose.
The concept behind Osmo Active is to optimize this fluid travel inside our intestines, so we can become better hydrated (or less dehydrated). They key, according to Sims, is as simple as making the concentration of the drink lower than that of the blood. She states that blood plasma osmolality is normally in the range of 285-290mOsm (milli-osmoles), assuming you are sufficiently hydrated. As such, we want our sports drinks to be below 280mOsm.
Had enough science? The punch line of all that mumbo-jumbo can be expressed in a single number – 3.2%. If there is one big secret to Osmo, that’s it. Osmo has a 3.2% solution, or 3.2 grams of carbohydrates per 100ml solution. This is also the source of a great debate – and the key differentiator between Osmo and most other drinks. What solution is appropriate? Here is a small sample of what’s on the market:
Osmo Active – 3.2%
Skratch Labs Exercise Hydration Mix – 4%
Gatorade (regular) – 6%
First Endurance EFS – 8%
Custom high-concentration mixes (Carbo Pro, bulk maltodextrin) – As high as you want
The higher percentage, the more ‘stuff’ is in the drink. According to Sims, most standard electrolyte drinks are in the range of about 330mOsm – significantly higher than that of our blood.
What happens if the drink is more concentrated than your blood? Dr. Sims says that you can still absorb it, but your intestines must first pull water away from your body (to dilute the solution) – so it can then be re-absorbed. This slows the whole operation, causing bloating and fluid sloshing – and reducing the amount of fluid that can be absorbed. In addition, we’re told that Osmo has a proprietary ratio of glucose to sucrose (which aid in fluid absorption), and uses sodium citrate rather than the usual sodium chloride (said to aid in fluid absorption and aerobic metabolism).
Testing
Rather than simply sending sample products to us, Osmo invited us to a formal test in Boulder, CO.
Several journalists and local athletes were scheduled for two days of testing in a hotel conference room. The protocol called for very controlled conditions:
Sunday 20 January, Please do the following:
1) 60 min spin at 50% of your max (think easy, easy recovery spin)
2) Immediately following that spin, please drink 8-10 oz non fat/ low fat chocolate milk, or OSMO Acute or Vega Recovery (If you are vegan). No other training please.
4) Record everything you eat and drink: time of day, what it was, how much (in enough detail that you can replicate each meal/snack exactly on the day before your second day of testing.)
5) Drink 0.18 oz of water per pound of body weight throughout the evening before bed.
6) SLEEP: this is important! Replicate the same bed and wake times for both testing sessions!
Monday 21 January-- NO EXERCISE UNTIL TESTING SESSION
1) Take your core temperature pill no earlier than 15 hours before testing, and no later than 6 hours before the test.
2) Eat your usual breakfast and record it per Sunday’s detail (you will have to have the exact same food and amounts on Wednesday morning).
3) Drink 0.18oz of water per pound of body weight throughout the morning.
4) NO CAFFEINE within 4 hours of testing. Please record amount and type of caffeine ingested (i.e. black drip coffee, espresso, yerba mate).
5) Consume your last bit of food 2 hours before testing (please record this as well; you will need to replicate this on Wednesday).
Tuesday 22 January:
PLEASE REPLICATE SUNDAY WITH REGARDS TO FOOD, SLEEP, AND TRAINING- 60MIN SPIN AT 50% ONLY WITH RECOVERY DRINK WITHIN 30 MINUTES OF FINISHING THE RIDE
Wednesday 23 January:
PLEASE REPLICATE MONDAY MORNING EXACTLY!
Before each test, we first had to pee on a urine test strip and weigh ourselves:
The rides started with a 15 minute warmup, then a 60 minute effort at 70% FTP, and finally a 15 minute all-out time trial.
For one trial, we were to ingest Osmo Active plus solid or semi-solid food. The second trial was liquid or gel calories of our choosing (whatever we would normally use). Fluid and calorie intake were both standardized based on body weight.
The order of the trial was randomized with a coin flip; I was Osmo first and ‘normal’ second. My solid food of choice was Honey Stinger chews (pink lemonade, to be exact).
During the test, we were asked for our perceived exertion and perceived level of thermal comfort (essentially – “How hot do you feel?”). This was also measured objectively via the core temperature pill I’d swallowed, along with a very fun tool – a thermal imaging camera. Here is a very colorful version of me during the test:
The camera allows spot measurement of temperature. The darker or more blue you are, the cooler you are.
In addition to temperature, we also recorded heart rate and power output. I happened to be in the middle of some power meter testing, so we weren’t at a loss for data:
With my first test being Osmo Active plus Honey Stinger chews, I was able to pick what I wanted for the second test. I’m a fan of EFS Liquid Shot, so that’s what I used.
Test Results
Before I really dive in to the results, I must note that I wasn’t able to follow the protocol to a T. I had another product event already scheduled in Boulder that week (Stages Power), which involved a hard effort the day before my first Osmo test. What to do? Being the scientist that she is, Stacy made the right choice – that was also the painful one. Hard ride on Sunday, and a test on Monday? Well – that means you need to do some sort of hard effort on Tuesday, so you go in to Wednesday in the same condition. My first thought was something to the effect of, “Holy cow this is going to be a hard training week…” Upon further reflection, I’m actually glad it turned out that way. Given the high training time requirement of triathlon and frequent hard workouts, this seemed more representative of what we might normally do during a stressful mid-season week.
On a subjective level, I felt roughly the same on both days. I slept the same amount and ate similar foods.
What does that all mean?
-Core temperature pill: My temperature stayed lower with Osmo
-Body weight: I lost less weight with First Endurance
-Hydration (USg): I stayed more hydrated with Osmo
-Thermal imaging of skin temperature: My skin was cooler with Osmo.
This didn’t quite make sense to me. It’s clear that my temperature was cooler with Osmo, but I was confused on the weight and hydration. How did I lose more weight with Osmo, but stay better hydrated? According to Stacy, “Cooler skin temperatures across the OSMO 15 min TT indicates greater sweat rate and evaporative cooling. Greater fluid absorption occurred as indicated by the USg hydration status (both trials started euhydrated, the OSMO trial conclude with a USg indication of euyhydration (<1% loss). Whereas the LQCal trial conclude with slightly less body mass loss but a USg indicating ~1-1.5% body water loss.”
In a nutshell, I had higher fluid throughput with Osmo. I was able to absorb more fluid, maintain more blood volume, sweat more, and stay cooler.
What about power output? This portion of the test was unfortunately limited due to something completely unforeseen – a non-adjustable magnetic trainer. I had a top gear of 53x12, and completely spun out the trainer before hitting my required wattage. We didn’t realize this until the time trial was already in-progress. The other trainer in the room was a fluid model with higher resistance, but was being ridden by another test subject at the time.
This being the case, I simply spun as fast as I could, and used the same trainer for both tests.
The numbers are striking. With my trainer limitation and non-standard training methods, I was curious to see if the other test subjects had similar results. Was my data bad? Was I just tired for the second test? Did I simply slack off and not spin fast enough?
Let’s look at the data for the entire group of 18 participants’ power files:
I’m not confident we can say that the data as perfect, as we were at the mercy of different power meters and head units. I was personally using both a Stages Power meter and a Powertap SL+, but other subjects had various Quarq, SRM, Powertap units – along with a slew of head units. I’m not aware of how each head unit was set up, nor if each rider set the zero offset before both tests (I did). In any case – even if the data happened to be exaggerated by a technology snafu (we don’t know either way) – the results are noteworthy.
This graph shows a compilation of core temperature and wattage for both the 60min steady state and 15min TT:
Where does this leave us? Based on the test results, it appears that Osmo Active works as advertised.
There is one (large) stone left unturned, however. How do we implement this strategy for long course triathlon racing? Also – how does Osmo differ from the other similar product on the market, Skratch Labs? Can we really implement this strategy that looks so good on-paper?
I posed these questions to Dr. Sims, both during the trials and in many subsequent emails. I expressed my concerns, and asked if she would be willing to create an Ironman nutrition plan for me – but only if I could provide the key limiters:
1. Aid station frequency and product availability
2. Equipment set up (number of bottles, location of bottles, number of jersey pockets, bento boxes, etc)
3. Special needs bags
4. The general amount of fuss I’m willing to deal with
After some thought, she agreed. In part two of this article, we’ll cover the details of the plan, along with my experience with Osmo so far. Also, we’ll hit on some of the more basic concerns – taste, price, and comparison to other products.
1. https://en.wikipedia.org/wiki/Osmosis
2. https://en.wikipedia.org/wiki/Osmolality#Osmolality
