if food and water are so vital to us staying alive, why don’t our bodies make it inside like plants do photosynthesis

Question: if food and water are so vital to us staying alive, why don't our bodies make it inside like plants do photosynthesis by absorbing simple ingredients? that would be soo much easier and make more sense because then dying would be less common.
- Keywords:
  body,
  food,
  photosynthesis,
  production,
  water
Asked by piwikiwi3 to Christina, Jess, Steve on 27 Jun 2013. This question was also asked by caitlingriffin1994.
- Steven Gardner answered on 27 Jun 2013:
  
  Plants don’t make water, they still need to get that from outside.
  
  I guess it’s a question of resources. Imagine a million plants all competing for the same nutrients and light, now imagine that one of those plants evolves so it can eat other plants (I’m speeding up and messing around with evolution here so don’t take that as a real example!). Suddenly the second one doesn’t need to compete with a million others, it can get them to do it’s energy conversion for it. So long as there are plants to eat it will thrive.
- Christina Pagel answered on 27 Jun 2013:
  
  There are lots of advantages to moving around (like avoiding floods/fires/climate problems etc) but moving takes a lot of energy – more energy (i should think) than you get from photosynthesis… so we evolved to use that convenient energy stored in plants and animals by eating them!

Question: if food and water are so vital to us staying alive, why don't our bodies make it inside like plants do photosynthesis by absorbing simple ingredients? that would be soo much easier and make more sense because then dying would be less common.