The fastest digesting foods are fruits I believe, followed by vegetables and meat takes the longest.
Hindus give the reason for them being vegetarian because it is important that we consume food thst has the most different genetic code to our own , they point to the fact that eating meat is the closest thing to eating our own kind and thst this is bad for us, especially due to the time it takes to digest.
They show what happens to meat in if you leave it out in the heat unrefrigerated for 2 days, the same time as it tskes a human to digest it, and at the same temperature and explain that the same rotting is taking place in our bodies as the meat is being digested and this is terribly unhealthy for us.
Fruits and vegetables get digested and the waste passed out much more quickly making them so much more healthy as well well as containing the different nutrients our body needs, which arent contained in meat. If they were, we could just create our own and wouldnt need to eat anything! Thats their logic anyway.
Lookup Sadhguru on Youtube and hear how he explains it, it may just change your life :-)