“Be kind; everyone you meet is fighting a hard battle.”
– Plato
credit: Sgt. Gooch
I know, I know – this is a problem everyone would love to have to deal with, I’m sure 🙂 For the serious, weight-conscious (or weight-class) athlete, though, too-low a body fat level can become a serious detriment to performance.
Mike Young, blogging for Elite Track, recently posted on the topic of how performance can be negatively affected by extremely low body fat levels. Now for your everyday Paleo/HIT practitioner, this phenomena is of little concern, as eating a simple, Paleo diet (to satiation) and following a sensible fitness program will naturally lead an individual to a 10-ish% (male) to 15-ish% (female) body fat level. However, this does become an issue for trainees who, for whatever reason, decides to manipulate the body to carry extremely low fat levels. Weight-class athletes and figure competitors/bodybuilders immediately come to mind here. Increasingly, however, CrossFit Games competitors and other power-to-bodyweight-ratio (P2BWR) conscious athletes (especially gymnasts, track and field athletes – even team-sport athletes) will attempt to squeeze-out just a little higher P2BWR by stripping off a few additional pounds of fat. More often than not, however, this attempt backfires. Not that the stripping away of additional fat stores is all that complicated (more on this in an upcoming post), but that at a certain point, performance (more precisely, force output and endurance) will absolutely plummet. Quoting, now, from Mike’s post:
“…I’ve noticed that people tend to perform better at slightly higher body fat percentages. Not “big” or “fat” by any means but slightly higher than rock bottom, paper thin-skin body fat values. In fact, other than some rare cases, most athletes don’t seem to perform their best when at their lowest body fat percentages. This seems to be especially true for activities placing a premium on strength or low end power. To throw out some observational estimated figures, I’d say that 7-10% body fat appears to be the sweet spot for performance and better for performance than 4-6% body fat (the lower limits of what is physiologically possible)…”
Now why this should be so leads to some rather interesting conjectures. Of course, unless we can attached a realistic “fix” to the “why(s)”, we’ve done little to help the athlete. Again, quoting Mike here:
“…Is this because peak performances usually occur during times when training volumes are lower…which when combined with unmodified caloric intake lends itself to increased body fat values? Or could it be that slightly higher body fat percentages facilitate more efficient neural transmissions? Perhaps it’s because achieving extremely low body fat percentages requires what is essentially a slight starvation that in turn affects performance. I’m not exactly sure but I’ve seen this phenomenon enough times in athletes I’ve worked with to question the usual paradigm that athletes should strive for the lowest possible body fat percentages…” (emphasis mine).
Viewing this through an evolutionary prospective seems to raise as many questions as does it provide possible answers. I agree with Mike on his observed 7 – 10% “sweet spot’ for peak performance, and if we combine this with my conjecture that following a strict Paleo diet (and eating to satiation) will naturally lead one to a 10-ish% (male) to 15-ish% (female) bodyfat level, we could argue that an ancestral hunter would be “on his game” and at his most lethal at what would be considered a natural body fat level.  Here’s where it gets a little more interesting, though. Let’s envision a time of ancestral scarcity, and of dwindling fat stores. Those of you who’ve reached a low body fat percentage and who’ve done any amount of intermittent fasting (IF), can attest to the feeling of “heightened acuity” and increased urgency or energy levels, the seeming lack of need to sleep for extended periods – rather tough to describe, but if you’ve been there, you know what I mean. Now maybe this is an evolutionary “boost before the decline”, a kind of “hail Mary” pass – the last ditch effort. But what if the hunt is still not successful, what then? The body has now hedged its bets, put all the chips on the table.
I don’t have a satisfactory answer for this yet, other than the realization of this scenario’s forcing the body into scavenge mode – the robbing of its own protein (muscle) stores, the forced consumption of poor quality (low energy density) food-stuffs, and the resultant insulin-induced energy storage spike.
We do know, though, that the body rebels against a perceived too-low fat level via reduced energy expenditure (via a slowed metabolic rate). But I also believe that the myelin sheath within the nervous system begins to degrade at extremely low fat levels, and that this also results in hampered performance – not only physically, but mentally as well. As Mike says, though:
“…Ultimately it doesn’t matter because repeated real-world performance improvements trump scientific explanation…”
True enough, at least for the athlete/practitioner, who’d be well advised to keep this phenomena in mind when juggling weight-class issues, maximal P2BWR, and ultimate performance. There are instances where dropping that last bit of fat to hit a lower weight-class/body weight level may actually be more of a performance detriment than an aid. As always, be fearless but wise in your n=1 experimentation.
A Quick Administrative Note:
Barring any unforeseen contractual meltdowns, it seems as though Meesus TTP and I have finally sold our house; doing our damnedest,by the way, to keep housing prices severely depressed. Anyway, the result of this is that the next few weeks will be rather frantic around TTP-ville (packing, moving, relocating, etc.), and will probably result in a diminished blogging rate – at least in the short term. On a positive note, this is where the Paleo/HIT combination shines brightest, and where other diet/lifestyle/exercise “plans” meet their Waterloo. Just as Paleo/HIT sustained me during the dark period of B’s passing, so it will during this stressful period.
In health,
Keith
Theory to Practice 