Sunday, October 7, 2012

The Female(?) Athlete Triad - Part III/III: Road to Recovery! Step #1 = "Increase Your Energy Intake"! Plus: Learn How to Calculate Your Resting Energy Expenditure (BMR)

You don't have to eat Burgers and French fries all day, but it's almost certain that you got to eat MORE than before. In this installment we will thus take a look on how much you'd minimally to function in your regular everyday life.
I have to admit I did underestimate the workload that would be associated with the SuppVersity Female(?) Athlete Triad Series. When I wrote the first part of this series, I originally did not even plan to have a second, let alone third part. Now, I've reached Part III and have to realize that the simple question "how much do I have to eat" can become pretty hairy. Not the least, because I personally have never been an advocate of meticulous calorie counting and yet cannot ignore the fact that I have to give you something you can start from... to cut a long story short, also to avoid falling victim to the aforementioned "bloggers triad", I will tackle the rest of this series, the "Road to Recovery" as I called it in as many steps as it will take: No renumbering just Step #1, Step #3, Step #3, ...

In view of the fact that each of those steps should contain at least one thing you can actually do, we will start out right with the single most important change you will have to make in order to escape the self-perpetuation vicious circle I've been outlining in the last installment of this series.

Step 1: Increase your energy intake! But how much do you need?

Figure 1: Dose-dependent effects of restricted energy availability on LH pulse amplitude (squares, top) and frequency (triangles, bottom) in subgroups of women with luteal phases of exactly 11 days and >11days.  Effects are relative to values at 45 kcal/lean body mass (Loucks. 2003)
If you take a look a the way the luteinizing hormone secretion becomes impaired, when your energy intake goes below a critical threshold of roughly 30kcal/kg (for men you will see propably see your T-levels plummet if you go below this level - diet or not!), it should be obvious that your first step towards recovery is to increase your basal energy intake, i.e. the amount of energy you consume irrespective of your daily energy expenditure, above this critical threshold.

For a 25-year old woman with a body fat percentage of 20% and a total body weight of 65kg this would imply that your daily energy intake must never be lower than 0.8 x 65kg x 30kcal/kg = 1560kcal - even when you are dieting.

Despite being based on empirical evidence, going solely by LH abnormalities is probably not the best way to estimate your energy requirements. Therefore, I have picked two practical alternatives for you to chose from:
  • The standard equation to calculate the basal metabolic rate independent of your daily activity levels, i.e. the Harris-Benedict equation reads (the values are in kg, cm and years, for weight, height and age, respectively)
    • REE (women) = 65.51 + 9.5663 x weight in kg + 1.85 x height - 4.676 x age
    • REE (men) 66.5 + 13.75 x weight  + 5.003 x height - 6.775 x age
    • Active (wo-)men need more than their REE (img
      Multiplied with the "correct" Acitivity Level Factors these REE values will also yield an estimation of your overall daily energy expenditure which is 1.53x, 1.76x and 2.25x higher than your REE depending on whether you are sedentary or lightly active (1.53x), active or moderately active (1.76x) or vigorously active (2.25x), with the latter being the category approx. 90% of those who are trapped in the athlete triad still belong to.
  • Probably more accurate since developed and tested with an athletic population, but reliant on way more information would be a recently proposed equation by Oshima et al., which reads
    • REE (men & women) = 2.3 x bone mineral weight + 4.5 x adipose tissue weight + 13 x skeletal muscle weight + 54 x rest weight*
      *(brain, liver, kidney, glands, skin, etc.)
    • It is easy to see that this equation has been developed to be used in professional studies. After all, the majority of people won't even know that there is a profound difference between both your fat mass and your total adipose tissue mass, as well as your "lean mass" and the amount of skeletal muscle tissue you are effectively carrying around.
* * *
While the calculation of your resting energy expenditure with the Harris-Benedict equation should actually be pretty straight forward and yields
Daily REE (Harris-Bendict) = 655.1kcal + 9.5663kcal/kg x 65 kg
+ 1.85kcal/cm x 170cm - 4.676kcal/year x 25 years
= 1474.51kcal
the same cannot be said of the more sophisticated equation Oshima et al. proposed. Not because it was more complicated to plug the figures into a calculator, but rather because you are unlikely to have the respective data handy.

How to use the Oshima equation without DXA data - An example

Since this is at least in my experience the parameter most of you will be missing, I base the following example calculation on the assumption that we don't have the quantitative data on Mrs Jane Average's bone mineral density and are thus not able to estimate the corresponding bone mass (in kg) by multiplying the bone mineral density (in g) by x 1.85 / 1000.
Figure 2: The individual contribution of the body compartments (based on Oashima. 2011 & Taguchi 2011) in the Oshima equation relative to total body weight in 57 male and 93 female athletes can serve as a basis to estimate your resting energy expenditure. The text provides an example how this is done for a 25y-old, 170cm, 65kg woman with 20% body fat. The same can be done for men & women from other "weight classes", the values are yet probably not representative of live-long sedentary individuals
For Jane Average, the athletic woman from our previous example, who had a total body weight of 65kg and a body fat percentage of 20%m we can still estimate all the parameter we need by extrapolating values from the data in figure 2 (don't tell me that's not accurate, you will be surprised ;-):
Do not count each salad leaf! As mentioned in the introduction, already, I have never been a fan of calorie counting. Part of the problem of the athlete triad is however that once you are in it, you have no baseline you could tweak by following my usual advise of logging your food intake for 1-2 weeks, taking stock and going from there. Likewise you can (for the reasons I explained in the last installment) not go by your appetite / hunger, simply because you have long "starved it away". If you really want to return to normalcy, however, you must not start to count the energetic value of each and every salad leaf, tomato, piece of broccoli or single rice corn you put into your. Therefore, the things you will count are ...
  • meats, eggs, fish, dairy, etc.
  • rice, (sweet) potatoes, oats, pasta, bread, etc.
  • coconut oil, olive oil, butter, ghee, sauces, etc.
  • any form of treat / fast and convenient food or caloric beverage
  • food supplements, e.g. protein shakes or bars
You will also count pieces of fruits and veggies with a caloric value similar to carrots, but whenever you catch yourself cutting off half of the asparagus spear you were just about to eat, eat at least another two + buttery Sauce Hollandaise on top ;-)
  • assuming that the body height of our woman is 1,70cm, she would have a BMI of 22.5 kg/m² and therefore fall into the middle category in figure 2
  • accordingly her bone mineral weight would be ~7% of her body weight, which allows us to estimate her total bone mineral weight to be 4.55kg
  • her total fat mass, which is ~85% of the total adipose tissue weight would be 20% of her body weight, i.e. 13kg; we need to multiply that by 1.18 in order to accommodate for the non-fat part of the adipose tissue and get a total adipose tissue mass of 15.3kg
Since the weight of the "other organs" (including brain, liver, kidney, skin, etc.) is subject to lower inter-individual differences, than the exact amount of skeletal muscle, we will use the purple 30% "rest / organ mass" value from figure 2 (remember with a BMI of 22.5 our exemplary woman falls into the middle category) instead of simply relying on the  common yet incorrect assumption that the skeletal muscle mass was was more or less identical to the difference of total body and fat mass:
  • to determine the weight of the metabolically highly active organs (compare the coefficients to those of the "purported fat burner" skeletal muscle - at rest, brain, liver, kidney, but also ovaries & co consume 4x more energy than muscle!) in the Oshima equation we  multiply the total body weight with0.3 (=30%) and get a a "rest weight" of 19.5kg
  • eventually we determine the skeletal muscle weight by simply subtracting all the values we have from the total body weight - viola, our exemplary woman has a skeletal muscle weight of 25.65kg
All that's left to do now, is to plug those values into the Oshima equation, which will then look like this:
Daily REE (Oshima) = 2.3kcal/kg x 4.55kg + 4.5kcal/kg x 15.3kg
+ 13kcal/kg x 25.65 kg + 54kcal/kg x 19.5kg = 1465.77kcal
So, assuming that I did not hit the wrong buttons on my calculator, this result is actually almost identical (8.74kcal/day) to the estimation the Harris-Benedict equation yielded. This in turn, goes to show you that within the "normal zone", into which Mrs. Jane Average certainly would fall, simple standard equations such as the often criticized, yet still widely used Harris-Benedict equation appear to be pretty accurate. At least, when we are talking about the minimal requirements of someone who's not doing much more than walk from the bed, to the fridge, to the car, to the table in his office, back to the car and ... you know what the average white-color worker does these days.

Extraordinary individuals have extraordinary energy requirements - and you are extraordinary!
Fortunately, you are none of those office "triseathletes" whose athletic triad consists of exhaustive in your office chair idling, extreme stressed in the car sitting and lazy on the couch lying... right? I thought so! And this is why there is no way that the ~1,500kcal will suffice to break out of the vicious circle of a real athlete's triad. 

On the contrary, it is however "as sure as eggs is eggs" that falling short of those minimal energy requirements is the single best recipe to fall victim to the very same triad.

Resting metabolic rate and real-life energy requirements

If you take another look at figure 1, the corresponding LH-based energy intake rule of thumb, I derived from the data by Loucks et al., as well as the coefficients (the factors in front of the parameters) in the Oshima equation, it should actually be obvious that those basal energy requirements are more or less "hard-wired" into our hypothalamic energy control system. With 54 out of 74kcal/kg body weight (73%) being used simply for the maintenance of organ functions, alone (!), there is not much room to conserve energy other than eating up the organs, the bones and the skeletal muscle and of course shutting down such superfluous organs as the ovaries or testes, and... hold on, aren't that all the symptoms of the athlete's triad?

Figure 3: Mean, median and minimal energy intake (in kcal/kg) in eumenorrheoic vs. amenorrheoic female athletes (data calculated based on an overview in Manore. 2002)
Against that background it is no wonder that my statistical makeover of the stats from a list of studies that was included in a 2002 paper by Manore, already suggests that the 1,500kcal are in fact an absolute minimum for the real light-weights among female athletes. Only in one of the 15 studies with datasets from 138 women on which the values in figure 3 are based, were the ~30kcal/kg body weight sufficient to prevent onset of amenorrhea. And when I am telling you that this group of female athletes also happened to be the group who consumed the highest amount of carbohydrates relative to their overall calorie intake per kg of body weight, I am actually already touching on the topic of the next installment, in which we are going to take a look on how you should distribute your overall energy intake across the macronutrient spectrum.
A pros pos, while you are waiting for the next installment of this series you should stop counting asparagus spears, calculate your resting metabolic rate and see where you are standing, in terms of your current caloric intake! And though I personally doubt both the quantitative validity of the activity level factors Harris and Benedict provide, you should not forget that chances are slim if not non-existent, that you will recover, if you don't aim for a 1.76x higher energy intake than your RMR calculations would prescribe on workout days.

  • Harris JA, Benedict FG. A biometric study of basal metabolism in man. Publ no 279. Washington, DC: Carnegie Institution, 1919.
  • Loucks AB, Thuma JR. LH pulsatility is disrupted at a threshold of energy availability in regularly menstruating women. J. Clin. Endocrinol. Metab. 2003; 88: 297–311. 
  • Manore MM. Dietary recommendations and athletic menstrual dysfunction. Sports Med. 2002;32(14):887-901.
  • Oshima S, Miyauchi S, Kawano H, Ishijima T, Asaka M, Taguchi M, Torii S, Higuchi M. Fat-free mass can be utilized to assess resting energy expenditure for male athletes of different body size. J Nutr Sci Vitaminol (Tokyo). 2011;57(6):394-400.
  • Taguchi M, Ishikawa-Takata K, Tatsuta W, Katsuragi C, Usui C, Sakamoto S, Higuchi M. Resting energy expenditure can be assessed by fat-free mass in female athletes regardless of body size. J Nutr Sci Vitaminol (Tokyo). 2011;57(1):22-9.