Modern Body?

Does anyone (besides me) ever think that if the human body were created from 'scratch' today it would be made to last longer than 16 hours before needing an 8 hour battery charge and food every 3 hours?? Seems a modern body would take you through a good 3-4 days before needing to be recharged...and be in need of sustenance every 24 hours. Just think how much we'd get done...but how many good meals we'd miss... hmmmm