Written Conversation :: Dr. Stacy Sims, Osmo Nutrition

I was introduced to Osmo Nutrition and immediately enjoyed the product for three reasons: one, I liked the taste, which isn't always the case when it comes to hydration and recovery products; two, I like that it's uniquely formulated for women and comes with the tag line "women are not small men" -- brilliant; three, It helped, noticeably with my performance during my last race

Osmo was formulated by Dr. Stacy Sims -- by a woman, for women -- and below she explains why it works so well. While the explanation is very science driven, after all, she is a doctor, the answers are also factual and I'm thankful to Dr. Sims for taking the time to break down the science of how women are not small men.


1) The tagline for your product, Osmo Nutrition is great "We're Not Small Men" and it really embraces the concept that your product is specific to a woman's needs.  Can you tell me about how your product works so well specifically for women? 

Ah. “Women are not Small Men.” Funny (ish) story behind the tagline…. My academic career has been to research sex differences, and every talk I give on sex differences or women specific lectures has always started with “women are not small men”. When I gave a talk at the USACycling Coaches Summit, the Osmo team loved the title of the talk (women are not small men) and that is how it became the tag line.

Why does it work so well specifically for women?  First and foremost, remember that all sports nutrition research originated on male subjects as women have been deemed "too difficult to study" due to the complexity of the menstrual cycle and designing studies around the two phases (follicular-low hormone phase, and luteal-high hormone phase; day 1 is the first day of bleeding and is the first day of the follicular phase). Since this has been the norm, all the recommendations on nutrition and training have just been generalized to women as the thought has been "well, it's good enough". I personally don't think so, especially when you realize how different we are from men-->

Okay, the key difference between men and women is that women have a menstrual cycle (and this also extends to birth control, and peri/post menopause)- the fluctuations of estrogen and progesterone affect much more than the reproductive system- these two hormones affect fluid balance hormones (aldosterone- which is key for sodium balance, and progesterone competes with the same receptor site as aldosterone; and arginine vasopressin aka AVP- this is key for water and thirst).

With high estrogen and progesterone (The 2 weeks preceding the start of your period), there are significant changes in a woman's physiology, with the peak of these changes felt ~5days before bleeding. The changes that happen include: a drop in the plasma volume (watery part of the blood) by ~8% (meaning less total blood for circulation and thermoregulation), an increase in core temperature by ~0.5'C (shortening the time to fatigue and decreasing heat tolerance), a change in metabolism to spare glycogen and increase reliance on fatty acids (reducing a woman's ability to hit intensities and reducing a woman's ability to lean up), an increased amount of muscle catabolism from progesterone (reducing the ability to recover well, and to lean up), an increased amount of total body sodium losses (again, from progesterone), with a reset of the plasma osmolality (lower, predisposing women to hyponatremia). Estrogen also blunts VO2max-from a metabolic and respiratory aspect (can't access carbohydrate to hit the intensities, and with an increased respiratory rate, it is hard to hit the top end of VO2). Estrogen and progesterone also affect central nervous system fatigue- most feel this as a lack of "mojo"- eg can't push through a hill or sprint when they ordinarily can thinking they are having a few shitty days on the bike- it's physiology, not fitness!

With birth control pills, the circulating amount of estrogen and progesterone is 6-8 times as high, and the "low hormone/placebo week" is actually not low hormone- estrogen rebounds and you end up with a high circulating amount of estrogen. The IUD is a much better option because it is just localized doses of progesterone- which significantly reduces the amount of hormones circulating.  Peri and Post menopausal women have an additional challenge- they have a predisposition to store abdominal fat (left over signals from estrogen), and have a significantly more difficult time maintaining muscle integrity- there is an increased catabolic drive which decreases muscle reparation and hypertrophy, meaning that this population has a difficult time gaining and maintaining lean mass, and the neuromuscular drive to produce power.   Men on the other hand, don't have any of the above.

2) You have different levels of hydration, suited for all workout needs. While the pre-load is best suited for athletes, those who train in extreme heat or involved with intense training, but can the woman who is a weekend workout warrior (yoga, Pilates, running on the treadmill or exercise on the elliptical) benefit from your Active Hydration product or should she stick to water as hydration?

Active Hydration is the best choice. Water actually doesn’t hydrate.. the body needs fluid that has a wee bit of sodium and potassium to pull the fluid across the intestinal cells. Prime example of this are the people who walk around with a water bottle all day, drinking drinking drinking, but peeing peeing peeing… and still being thirsty.

3) There's a difference in recovery times for men and women, but say "NO" to chocolate milk or soy products. Can you elaborate on this?  

Sure. Chocolate milk has become all the rage with the the 4:1 ratio of carbohydrate to protein- but this is a guy’s ratio  (women need a 3:1 ratio) and soy- the amino acid profile of soy is enough to stop the breakdown effects of exercise and stop cortisol, but it isn’t enough to promote muscle cell synthesis (there are a few newer studies looking at the mix of whey and soy as recovery and they are finding a signal for synthesis, but the research did not tease out the whey vs soy aspect…)

4) What is the one nutrition tip that you can give, which would benefit all women, whether they are an Ironman competitor or prepping for their first 5k race? 

Change your body composition OFF the bike/run- eg don’t be sparse in your fueling and hydration needs for your sport; you have plenty of time in and around training to alter your diet for body composition change!

5) When I launched my site, I wanted to continue to grow as a person, but also find Genuine Joy in each of those challenges and experiences. What is something that brings you Genuine Joy?

Uncompromised, unattached, pure emotional Genuine Joy would be my daughter. She’s only 2, and being a parent has changed my entire interaction with the world.