Diet actually plays a huge part in our ability  too meditate and too stay positive. What we eat clearly shows our attitudes towards  all living beings, that is  towards our understanding  of the soul. An enlightened soul will automatically  have love and empathy  towards  all life , including  environment.  So thus you can see why  an enlightened  soul would be a vegetarian  or vegan. This  isn't  always the case, some people  who eat plant based diets can also be assholes lol. But believe me it will help your concentration in meditation and in life in general. Heres a good website too back up my claims.www.wix.com/danny108/holy-smoke