Playing with my own little WIP modpack and for some reason my memory usage was extremely high. Decided to check out the spark report and this was my results: here
Latest.log if it helps any bit: (Not uploaded as a gist due to massive file size) here

Posting research here for personal reference

The issue here is a mix of CreativeTabs being constantly reloaded (Probably not us? Thinking its Owolib) and the fact that when we do creative tab stuff we run a registry look for every block item. We MIGHT be able to just throw a reference to the block item in the class, but the way of doing so that Im thinking is a horrible idea.