True, I only included kJ equivalent because some countries use kJ on nutritional panels instead of Calories. Actual conversion rate of human energy stores to usable power is, at a guess, more like
Calories * 0.25 * 0.6 * 0.8 - dt
where t is time, d is the self-discharge rate of the battery, 0.6 is the efficiency of the generator, and 0.8 is the efficiency of the battery.