Michael Phelps apparently consumes a wopping 12,000 calories per day. Since he doesn’t look like he’s gaining wait, he must be doing 12,000 calories’ worth of work during his exercise regimen. If only we could harness that energy instead of wasting it swimming laps, it surely must be worth a pretty penny, right?
Nope.
The nutritional calorie (Cal) is 1000 cal (the physicist’s calorie), which comes to 4,200 J (Joules). Counting all taxes and fees, the retail price that I pay for electricity (one of the most expensive forms of energy) is 20 cents per kW·h, or 20 cents per 3.6 MJ. Altogether, then, one day of Michael Phelps’ physical effort is worth about $2.80.
If Michael Phelps were ever to sell just his physical labor, it wouldn’t even pay for a coffee at Starbucks. Conversely, even an “unskilled laborer” is payed almost entirely for his skills – the value of his labor alone is virtually nil.
This is why John Henry was doomed, and why the opening scene of Conan the Barbarian is economically implausible.