For the second time yesterday, I deliberately loaded up on carbs in preparation for a workout. For the second time in a row, I achieved a new personal best according to my own incredibly geeky workout-difficulty scale. Want to know how geeky? Here’s the formula.

diff = log2(minutes) + log1.1(calories/minute)

To put it in perspective, that means that a one-hour workout at caloric rate X is equivalent to a half-hour workout at rate X plus 10%. It’s about the twentieth formula I’ve tried, and gives results that very closely match my subjective impression of how difficult a workout is. It’s useful because it gives me a good idea what difficulty level I should shoot for when I change the duration of my workout. But that’s not really what this article is about.

For some time now, I’ve been advocating the “Atkins can go jump” diet plan, and similar (often even more colorful) variants. The fact that I’ve been getting tangible results from the all but forbidden practice of carbo-loading tells me that I’ve reached two important milestones in my exercise program.

  • First is that it’s no longer about weight, which by the way seems to have stabilized between 170 and 175 pounds. Obviously I could lose more weight if I didn’t eat more on workout days, but then I wouldn’t get as much of an aerobic workout.
  • Second is that I’ve reached the point where I’m likely to run out of fuel before I run out of aerobic capacity if I don’t go out of my way to load up beforehand. I’m no expert on exercise physiology, but my impression is that not too many people other than marathon runners and long-distance cyclists really hit this threshold (energy-bar marketing efforts notwithstanding) so I feel pretty good about that.

The best thing about this, of course, is that now I have an excuse to load up on McDonalds fries a couple of times a week.