Exercising pre/post workout

I really enjoyed exercising before I started having stomach issues , but with the food intolerance came the tiredness etc, which i struggled with when it came to the running , I would come to a point where i had nothing more to give like the runner’s wall but 10 times worst ,

As of today i started running again i felt really good and i’ll see how it goes to see how much i can do of it,

I have looked up some food I would now need to consume , One of the things is Chocolate milk (coconut) post run and jacket potato.

Do you do exercise ? if so what do you eat to help you pre / post workout !

I am still on a look out for Oatless Granola bar recipe or something similar to have post work out.