Or being as it’s a sugar right, would I just become diabetic if I wasn’t working out constantly?
In: Biology
The energy required to keep a human going is far more than photosynthesis could provide you would need a surface area similar to that of a small tree.
Dude is onto something. Let’s see who’s gonna file a copyright for sunlight. Might be nestle or amazon or Elon Musk.
Photosynthesis, even under ideal conditions, would produce less than 10% the energy a human needs to survive (I can go through the maths if you want). But the cost of being photosynthetic is high because you need the appropriate cell structure which animals don’t have. While it may not be technically impossible for animals to have such an ability, the cost to benefit ratio simply isn’t there. It’s much more effective to use that energy and time building the photosynthesis cells to instead make bigger muscles so you can catch more food/run away from predators for example.
There is a reason plants don’t move around much.
First of all, [photosynthesis](https://en.wikipedia.org/wiki/Photosynthesis) USES sun energy to force water and carbon dioxide to recombine into sugar, which is then combined into [cellulose](https://en.wikipedia.org/wiki/Cellulose) which forms the body of the plant. It doesn’t produce energy for the plant, it consumes energy to create material (from water and air) to grow the plant.
We actually do the opposite of photosynthesis. We eat the sugars (plants), and our cells BURN the sugars with the oxygen that we breathe, producing carbon dioxide and water, and a lot of energy. We do the exact opposite reaction to photosynthesis.
The carbon dioxide and water get recycled, from the atmosphere to plants to animals to the atmosphere to plants again. It’s a cycle.
In any case, you get a lot of energy from food + oxygen, a lot more than you would get if your skin surface was photosynthetic. Gasoline engines get a lot of energy out of burning gasoline; in order to get that same energy from sunlight (with solar panels), you’d have to have a solar panel 30 m x 30 m (100 ft x 100 ft), the size of someone’s yard, basically. To get the same energy as we get from food, we’d likely have to have a tree’s branches and leaves (I’m not going to do the math).
If you take a broad view of photosynthesis as not just making energy, but making nutrients, then humans already do something similar. Our skin converts cholesterol into vitamin D using sunlight.
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