Why are humans not capable of photosynthesis?

The short and obvious answer is because we don't need it. The two chocolate covered nuts I just ate contained more energy than a photosynthetic man could accumulate in an hour of full sun. read more

So if you ask “Why humans are not capable of photo-synthesis”, one possible view could be that because they evolved against it, or rather to survive against photo-synthesis’ poisonous by-products. read more

To conclude: humans can't go through photosynthesis since human biological plan simply isn't evolved for it----with a lack of chloroplasts and chlorophylls as well as supporting structures such as cell walls----in other words, a general mismatch between human biology and photosysthetic biology. read more