system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do vitamins give 200%, 500%, etc. of the recommended daily value?
gpt
Pills are not a very good delivery method of vitamins. When your body eats it kicks into digestion mode, and absorbs nutrients and vitamins efficiently. If you only take a pill, your body does not go into digestion mode, so it does not as efficiently absorb the vitamins. To compensate for the loss of absorption, pills just contain a greater than required amount. 

EDIT: Wow, a lot of responses. You can overdose on certain vitamins, but it would take a lot of that vitamin to have that effect. You could take 15 one-a-day vitamin pills and very likely still be fine, but if you take 15 of them for like two weeks, you're probably going to have a bad time. 

It is ok for things like Emergin-c or 5-Hour Energy to have a billion percent of your vitamin c and b because those two vitamins are water soluble, so you can not od on them, you just pass the surplus in your urine. Fat soluble vitamins, the excess is stored in your fat, then if you go through a process where you lose a lot of fat, you can release a large amount of the stored vitamins that were stored in your fat, making you sick.

Taking the vitamin with food probably does aid in absorption, but just follow the directions on the bottle, without an actual medical condition requiring extra vitamins, you aren't going to benefit from absorbing twice the recommended amount. 

Gummy vitamins may work better, but more than likely their only measurable benefit over non gummy vitamins are that kids are more likely to take them. There are not enough calories in a gummy vitamin to put your body in digestion mode, unless you take like 100 of them, which would potentially cause the same od problems previously mentioned.