system
Given the following post, respond as if you're commenting on Reddit:
human
If a human needs 2000 calories per day, could a human be said to run on 96 watts?

2000 kilocalories = 8360000 joules 

1 day = 86400 seconds

8360000 joules/86400 seconds = 96 watts

I have to be doing something wrong here. We don't require on average less than a lightbulb, do we?
gpt
Surprising as that may sound, you are right, the ballpark power expenditure of humans is roughly that of a 100W light-bulb running constantly. If that sounds surprising, keep in mind that incandescent lightbulbs are extremely inefficient, with less than five percent of the energy put in being converted to visible light. This is because the bulbs are black body emitters, which need pretty damn high temperatures (about 3000K) or so to emit significant amounts of visible light and most of the energy used to heat them up ends up being dissipated as heat (e.g. as infrared thermal radiation). 

Edit: An interesting tangent is that lighting, because it is both so ubiquitous and inefficient is actually responsible for a huge fraction of our energy consumption, lighting eating up roughly 20% of all the electricity produced. This is why the switch to significantly more efficient sources such as LEDs may have a large impact on reducing electricity/energy consumption worldwide.