Always be suspicious of the phrase "up to".  The guy who spends literally all day twirling his pencil and tapping his feet might burn 350.  We've all known someone who always had to be in motion and if you're moving 14-16 hours a day, you're going to use some energy.  Redditors, of course, are interpreting this to mean their hourly ass-scratching burns 350 calories a day so they've earned at least one more mountain dew.